Canine Reproduction
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Clinical Approach to Vaginal/ Vestibular Masses in the Bitch
Krongthong Manothaiudom, DVM,* and Shirley D. johnston, DVM , PhDt
Vaginal/vestibular masses in the bitch may involve the vestibule, the vagina, the urethral orifice, or a combination of these structures. Bitches with vaginal/vestibular masses may show abnormal clinical signs of the reproductive or urinary system or may be asymptomatic. Neoplastic masses may metastasize to other reproductive organs or to other organs of the abdomen and the thorax. Misdiagnosis of vaginal/vestibular masses leads to ineffective treatment and wasted time and money and can be harmful to the patient. The purpose of this article is to review the causes of vaginal/ vestibular masses reported in the bitch, present a survey of 44 cases of such masses identified retrospectively at the University of Minnesota Veterinary Teaching Hospitals, and describe a suggested method of clinical evaluation of dogs with these masses in a practice setting. CAUSES OF VAGINALNESTIBULAR MASSES Vaginal/vestibular masses may occur in both intact and spayed bitches of any age and in individual bitches of any breed. Types of vaginal/vestibular masses in the dog include vaginal prolapses, vaginal neoplasia, urethral neoplasia, and less common nonneoplastic masses such as uterine prolapse, clitoral hypertrophy, vaginal polyps, vaginal abscessation, or hematomas. Vaginal Prolapse Vaginal prolapse (vaginal hyperplasia, vaginal hypertrophy, estrual hypertrophy, vaginal eversion, vaginal protrusion) is characterized by marked edema of the submucosa and stratified squamous epithelium lining From the University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota *Department of Clinical and Population Sciences tDiplomate, American College ofTheriogenologists; Associate Professor, Department of Small Animal Clinical Sciences Veterinary Clinics of North America: Small Animal Practice-Vol. 21 , No. 3, May 1991
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the vaginal lumen, resulting in prolapse of a dome-shaped or doughnutshaped mass of tissue into the vaginal vault and through the vulvar cleft. 20 • 41 It occurs mainly in young, intact, large-breed dogs in proestrus or estrus and occasionally occurs during pregnancy or at parturition, when it interferes with normal delivery. 5• 11 • 20• 29 • 42• 46 • 52 The degree of vaginal tissue protrusion can be classified into three types. 41 Type l is slight to moderate eversion of the vaginal floor cranial to the external urethral orifice; the everted tissue does not protrude through the vulva. Type 2 is complete prolapse through the vulva of a broad, tongue-shaped mass with a narrow base or a dome-shaped mass; both originate on the floor of the cranial vagina. 20 • 42 Type 3 is complete prolapse of the entire circumference of the vaginal wall, which presents a dougnut-shaped or ring-shaped mass. 41 · 42· 46 The mean age of 65 affected dogs was 2 years , and ages ranged from 7 months to 11 years. 20 This disorder has been reported in a number of breeds and may be seen in certain families of purebred dogs, suggesting a hereditary breed predisposition. 8• 20· 41 • 46 Presenting signs of vaginal prolapse include the presence of a mass protuding through the vulva, licking at the mass, difficulty in urinating, and failure to achieve normal mating. 20 The protruding mass appears as a pink, pear-shaped, smooth, tumor-like structure. 28 • 29 Vaginal prolapse may be an emergency if prolapsed tissue is dry, traumatized, and necrotic or if the pressure of the mass leads to concurrent dysuria or oliguria. 12· 29 The minimum data base required for patients with vaginal prolapse are history, physical examination findings, and vaginal smears in young bitches. Older bitches require vaginal mass biopsy to distinguish vaginal prolapse from neoplasia. Laboratory findings in the hemogram, clinical chemistry profile, and reproductive hormone assays (estradiol or progesterone) of affected bitches are within normal limits. 20 • 36 Spontaneous regression of vaginal prolapse occurs after estrus or following parturition. 12• 20 • 41 • 42 The recurrence rate of vaginal prolapse in affected bitches is estimated to exceed 66%. 20 Treatment of vaginal prolapse in the bitch can be attempted by several methods depending on the breeding future of the affected bitch. These include conservative treatment by topical lubrication with use of an Elizabethan collar and induction of ovulation in the bitch in the follicular phase with gonadotropin releasing hormone (2.2 j.t.g/kg intramuscularly) to shorten the time of estradiol release before ovulation. Excision of the prolapsed tissue in late estrus or early diestrus may be considered in bitches intended for future breeding. 20 Permanent prevention of vaginal prolapse is by ovariohysterectomy. 1• 12• 20· 42 Vaginal Neoplasia Vaginal neoplasia is the second most common reproductive neoplasm in the bitch after neoplasms of the mammary gland and usually occurs in the older bitch. 6 · 9 · 35 The most common canine vaginal tumors are leiomyomas and transmissible venereal tumors. 4 · 6 • 40 • 45 • 47 Mean age of occurrence of vaginal neoplasia in the bitch is about 10 years. 4• 45 The most common clinical signs of vaginal neoplasia in the bitch are the presence of a mass protruding through the vulva and the presence of
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vaginal discharge. 14• 24 · 28 • 44 • 46• 48 Less commonly, vaginal tumors may cause mechanical interference with surrounding structures when they become large, resulting in stranguria, tenesmus, dysuria, urinary incontinence, or perineal swelling. 19• 39· 45· 47· 49 Diagnosis is based on history and vaginoscopic and physical findings ; exfoliative vaginal cytologic evaluation may be of value with some tumors.34 · 35 Definitive diagnosis is determined by surgical pathology. The treatment of benign vaginal tumors is surgical excision. 19 The leiomyoma may occur as a solitary ()r multiple extraluminal or intraluminal mass. 16• 23· 25 Extraluminal leiomyomas usually arise in the roof of the vestibule, causing bulging of the perineum . Intraluminalleiomyomas usually arise from the vestibular wall and protude from the vulva. 25 They may grow to be 10 to 12 em in diameter. The transmissible venereal tumor tends to be common in areas where dogs are free roaming, and the disease is rare where dogs are controlled. 23 The mode of transmission is by mating or mucous membrane contact with the tumor. 23 These tumors usually originate from the submucosa of the dorsal vaginal wall, in the posterior vagina at the junction of the vestibule and vagina, and, sometimes, at the external urethral orifice. 23 · 32 The size ranges from 0.5 mm to over 10 em in diameter. 15· 17• 30• 33 This tumor is a solitary or multiple, cauliflower-like mass, which is friable and commonly ulcerated. 23 • 32 · 37 Metastasis is uncommon but may occur to regional lymph nodes. 23 • 32 Spontaneous regression occasionally occurs without treatment. 5 • 7 • 23 The tumor responds to a variety of modes of treatment such as surgical removal, radiation, and chemotherapy. Recurrence after surgical excision may occur. Canine vaginal tumors are staged according to behavior of the primary tumor (T), regional lymph node (inguinal, internal iliac, sacral) involvement (N), and evidence of distant metastasis. 51 Because stages, progression, and prognosis of malignant vaginal tumors have not been reported together, staging data are now used to completely characterize tumor extent rather than to predict tumor behavior. Urethral Neoplasia
Canine urethral tumors can be categorized into two types on the basis of tissue origin: Epithelial tumors, such as carcinomas, and mesenchymal tumors, such as leiomyomas. Most tumors of the urethra are malignant, and metastatic urethral tumors are rare. 27 They are more common in female than male dogs. 10 In one report, seven of seven affected bitches were spayed, 26 and in another, 8 of 19 bitches were spayed. 10· 26 The size of affected dogs tends to be small to medium (10-25 kg) . 10 These tumors occur in old dogs ranging from 10 to 12 years. 26 The mean age is 10.2 years. 10 Transitional cell carcinomas and squamous cell carcinomas are common in the distal urethra of the bitch. 44 • 48 The histologic appearance of these tumors may be similar at the time of neoplastic cell replication. 3· 22 • 44 Urinary tract carcinomas can involve the vagina, vestibule, or both. The most common clinical signs are stranguria, hematuria, and hematocolpos. 26 The most common clinical sign of bladder involvement is dysuria. 10 Digital examination of the vagina and vaginoscopy are the most helpful and rapid methods for presumptive diagnosis of urethral neoplasia in the
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bitch. Cytologic examination of urine sediment is a useful tool but is diagnostic in only 40% of cases. 44 Definitive diagnosis of neoplasia is made by histologic evaluation of biopsy tissue. 35 Unfortunately, urethral tumors usually are not diagnosed until an advanced stage. 26 Other Nonneoplastic Vaginal/Vestibular Masses
Uterine prolapse occurs infrequently in the dog but may occur just before or after parturition. Primiparous and ·multiparous bitches may be affected. 31 The cervix, one uterine horn, or both horns can prolapse partially or completely. 38• 50 The prolapse usually occurs after delivery of the last fetus. 18 Clinical signs include vaginal discharge, abdominal pain, straining, restlessness, and protrusion of the mass from the vulva. 50 Diagnosis is made on the basis of the bitch's history of pregnancy and parturition and the appearance of the mass. Treatment depends on the animal's physical condition. If the animal and the uterus are healthy, manual reduction can be done. If not, excision of the uterus and reduction of the stump should be performed. 43 Clitoral enlargement can occur in bitches and in male pseudohermaphrodites. 13 Administration of exogenous androgens or anabolic steroids may lead to clitoral hypertrophy and the presence of an os clitoridis in the bitch. If the bitch is given androgens during pregnancy, clitoral enlargement may be seen in female puppies. Some bitches with hyperadrenocorticoidism also have been reported to show an enlarged clitoris. 42 • 53 Clitoritis and vaginitis may result from irritation of the enlarged clitoris protuding through the vulvar cleft. Affected bitches frequently lick the vulva. Diagnosis is based on history, inspection of the clitoris at the vulva, and measurement of endogenous adrenocorticotropic hormone or results of a dexamethasone suppression test. Treatment includes topical antibiotic ointment to relieve irritation and inflammation, removal of the androgen source, or excision of the enlarged clitoris. The clitoris regresses to normal size when the exogenous androgen is withdrawn. If an os is present, clitoral enlargement may persist. 42 Vaginal polyps (fibropapillomas) are common in aging bitches. They occur during the later part of the estrous cycle as small, occasionally ulcerated nodules, with variable hemorrhage. Treatment of choice is surgical removal. Recurrence is rare. 21
A RETROSPECTIVE SURVEY OF 44 CASES OF VAGINAU VESTIBULAR MASSES IN THE BITCH Material and Methods Data in this study were obtained from 44 case records of bitches with vaginal/vestibular masses seen at the Veterinary Teaching Hospital, University of Minnesota, between 1981 and 1990. Vaginal masses seen included vaginal prolapse (18), clitoral enlargement (1), benign vaginal neoplasia (14-6 leiomyoma, 5 fibroleiomyoma, 1 fibroma, 1 transmissible venereal tumor, and 1 lipoma), malignant vaginal neoplasia (6, 3 carcinoma, 1
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adenocarcinoma, 1 squamous cell carcinoma, and 1 leiomyosarcoma), and malignant urethral neoplasia (5, 3 transitional cell carcinoma, 1 melanoma, and 1 transitional cell carcinoma and fibrosarcoma). Signalment, presenting complaints, history, physical examination, and laboratory findings (vaginal cytologic evaluation, vaginoscopy, hormone assay, clinical chemistry, hematology, ultrasonography, radiology, urinalysis, gross pathology, and histopathology) were tabulated and categorized retrospectively. Signalment Vaginal/vestibular masses were present in bitches of different ages, breeds, and sizes (Tables 1 and 2), and in both intact and spayed bitches. The age of bitches with vaginal prolapse ranged from 7 months to 16 years; the majority of masses were present in intact bitches (16/18) under 4 years (11/18) of large breeds (11/18). The single bitch with clitoral enlargement was 6 years old and was a small-breed spayed female . Vaginal tumors were present in bitches from 4 to 15 years of age (mean, 11 years), and there was no breed predisposition. Thirteen of the twenty bitches with vaginal tumors were intact. Benign vaginal tumors tended to occur in small-breed (6/12) rather than medium- (3/12) or large-breed (3/12) animals. Malignant vaginal tumors occured in large-breed bitches (4/8) more than in medium(2/8), small-breed (118), or giant-breed (118) bitches. Urethral tumors Table 1. Age Distribution of 44 Bitches with Vaginal/Vestibular Masses DIAGNOSIS
AGE (YEARS)
0.7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Unknown
Vaginal Prolapse
Clitoral Enlargement
Neoplasia Vaginal
1 4 3 1 2 2
Urethral
1* 1*
lt 1* 1* 1t, 1* 2t 2t, 1* 2t 3t, 1* 2t
1
1
1 1
Range
0.7-16
6
Mean
4.6
6
Total
17
4-15
6-12
11
8.6
20
5
* = malignant neoplasm; t = benign neoplasm.
TOTAL
1 4 3 1 3 3 3 3 2 0 3 3 4 3 4 2 1 1
44
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Table 2. Breed Distribution of 44 Bitches with Vaginal/Vestibular Masses NEOPLASIA
(0--20 lb) Miniature Poodle Poodle Pekingese Chihuahua Cockapoo Chihuahua/Terrier Lhasa Apso/Poodle Pekingese/Poodle Total (11)
VAGINAL
CLITORAL
PROLAPSE
ENLARGEMENT
Vaginal! Vestibular
Urethral
SMALL BREEDS
MEDIUM BREEDS (21-50 lb) Australian Shepherd Beagle English Springer Spaniel Scottish Terrier Smooth Coat Collie German Shepherd Cocker Spaniel/Poodle Mixed Terrier Puli Total (12)
(51-100 lb) Labrador Retriever Golden Retriever German Shepherd Collie Shepherd/Retriever St. Bernard Mixed St. Bernard Old English Sheepdog Weimaranner Dobermann Pinscher Irish Setter Australian Shepherd Walker Hound Total (18)
1t 1
lt 1t 1t 1t
lt, * 1t 2
7
1* 1t 1* 1t 1t 1 1 5
5
2
LARGE BREEDS
GIANT BREEDS(> 100
Boxer Mastiff Golden Retriever Total (3)
1
1* 1t 1t 1 1*
1 3 1
1* 1* 1*
1 1 9
7
2
lb) 1,*t 2
* = malignant neoplasm; t = benign neoplasm, * = transmissible tumor.
protruding into the vagina as masses occurred in one intact and four spayed bitches from 6 to 12 years old, with no size predisposition. History The most common historical complaint was presence of a prolapsing vaginal mass (Table 3). This sign was found in dogs with vaginal prolapse, vaginal neoplasia, and urethral neoplasia. Other major clinical signs were
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presence of a vaginal discharge, dysuria, and increased frequency of urination (pollakiuria). Estrous bitches were represented only in the vaginal prolapse group (five bitches). Signs referrable to the genital system were the most frequently reported (Table 3); 3 of the 44 bitches had no historical problems identified in the history. The duration of the vaginal mass in the bitch with clitoral enlargement and in 12 of the 20 bitches with vaginal neoplasia prior to presentation was reported to be more than 1 week. Duration of vaginal prolapse prior to presentation varied from 1 day (1118), to 1 day to 1 week (3/18), to more than 1 week (3/18), and was not reported in 11 of the 18 patients. Mass progression was reported in 1 of 18 bitches with vaginal prolapse, 4 of 20 bitches with vaginal neoplasia, and 1 of 5 bitches with urethral neoplasia. Mass regression were reported in 3 of 18 bitches with vaginal prolapse and in 1 of 20 bitches with vaginal neoplasia. Previous treatments of the vaginal mass included ovariohysterectomy, vaginal mass excision, cauterization, purse-string suture at the vulvar cleft, application of an Elizabethan collar, and topical antibiotics. One vaginal prolapse and two vaginal tumors recurred after ovariohysterectomy, and one vaginal prolapse and two vaginal tumors recurred after vaginal mass excision. Physical Examination Findings Abnormal physical examination findings of the urinary system in bitches with vaginal masses included presence of a large urinary bladder and Table 3. Clinical Signs in 44 Bitches with Vaginal/Vestibular Masses VAGINAL
CLITORAL
PROLAPSE
ENLARGEMENT
(N = 18)
(N = 11)
NEOPLASIA
Vaginal/Vestibular (N = 20)
Urethral (N = 5)
TOTAL
10 3
6 6 1
1 1
4
5
1
1
1
2 3
17 11 1 11 3 5
GENITAL
Vaginal prolapse Vaginal mass/lump Vaginal ulceration Vulvar discharge Vulvar bleeding Licking at the vulva Vulvar swelling
4
1
5
3
3 1
1 4 2 2
2 13
URINARY
Hematuria Inappropriate urination Polyuria Dysuria Pollakiuria Nocturia Could not urinate
4
1 1 1
1 5 4
7 4
1
GASTROINTESTINAL
Vomiting Diarrhea Straining Anorexia
2
1
1 3 4
1 1 1
3 2 5 4
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presence of a mass protuding from urethra. In the genital system, the most common finding was the presence of vaginal tissue prolapsed through the vulvar cleft (l0/18 cases of prolapse and 6/20 cases of vaginal neoplasia). The next most common findings were the presence of vaginal thickening, the presence of an intravaginal mass, vulvar swelling (5/18 cases of prolapse, 1120 cases of vaginal neoplasia, and 115 cases of urethral neoplasia), presence of a mammary nodule (2/18 cases of prolapse and 3/20 cases of vaginal neoplasia) and presence of vulvar discharge (mucopurulent in one case each with vaginal and urethral neoplasia; sanguinous in one case each of prolapse and vaginal neoplasia, and serous in one case each of prolapse and vaginal neoplasia). Less common findings were mammary gland enlargement in the bitch with the enlarged clitoris, inguinal hernia, hypoplastic vulva, perivulvar tissue distention, perineal bulging, perineal dermatitis and infection, and vaginal hyperemia. Lymph node enlargement was present in the inguinal node in one bitch with a prolapse and in the popliteal nodes of one bitch with prolapse and one bitch with vaginal neoplasia. Various other unrelated abnormalities were reported for the musculoskeletal system, eye, skin, ear, heart, mouth, and respiratory system of various affected bitches. The vaginal/vestibular masses were red (6/18 prolapses, 2/20 vaginal tumors, 115 urethral tumors), pink (3/18 prolapses), red with blackened portions (2/10 vaginal tumors), white and black (1120 vaginal tumors), and white (1120 vaginal masses). The size of the vaginal masses of 13 bitches ranged from 2 em to 16 em in diameter. Two transmissible tumors in a bitch were 2 and 5 em in diameter. The size of prolapsed vaginal tissue in six bitches ranged from 1 em to 7.5 em in diameter. The size of the urethral tumors in three bitches ranged from 1 em to 3 em in diameter. The shapes of the vaginal/vestibular masses were variable, including an elongated vaginal prolapse mass, a stalked vaginal prolapse mass, a spherical vaginal tumor, an irregular urethral tumor, and a conical urethral tumor. Masses were movable (one prolapse, two vaginal neoplasms), pedunculated (two vaginal neoplasms), nodular (one vaginal neoplasm), ulcerated/eroded (one prolapse, one vaginal neoplasm), necrotic (one prolapse), and/or smooth (three prolapses). Consistency of the masses was recorded as firm in one prolapse and four vaginal neoplasms and firm with some soft areas in one vaginal neoplasm. Vaginal smears of affected bitches showed cytologic evidence of proestrus in two bitches with prolapse, estrus in three bitches with prolapse and one bitch with a vaginal neoplasm, and diestrus in three bitches with prolapse and two bitches with vaginal neoplasms. Vaginoscopy The sites of origin of masses observed vaginoscopically were recorded as ventral vagina (one prolapse and one vaginal neoplasm), vaginal mucosa surrounding the external urethral orifice (one urethral neoplasm), vaginal mucosa cranial to the external urethral orifice (one vaginal neoplasm), and urethral tissue protruding into the vagina from the external urethral orifice (one urethral neoplasm).
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Radiology and Ultrasonography Survey caudal abdominal, perineal, and thoracic radiographs, ultrasonograms of the vaginal mass, and retrograde vaginograms, urethrograms, cystourethrograms, and radiographs after barium enemas were taken of some of the animals with vaginal masses. The descending colon was displaced in one bitch with a vaginal neoplasm and in one bitch with a urethral neoplasm. A mass was demonstrated in the urinary bladder of a bitch with a vaginal neoplasm, and the urinary bladder was distended in another. Vaginal and uterine masses were detected radiographically or ultrasonographically in three bitches with vaginal neoplasia. The lungs appeared radiographically normal in six bitches with vaginal neoplasia and two bitches with urethral neoplasia and showed evidence of metastatic disease in one of the bitches with vaginal tumors. Other Laboratory Findings Blood samples were collected from 28 of the affected bitches for routine hemograms and from 25 bitches for routine chemistry profiles; no abnormalities were noted in any of the samples. Serum progesterone concentrations in three bitches with prolapses were more than 2 ng/mL, indicating that they were in the luteal phase of their cycles. Serum estradiol and progesterone concentrations were undetectable in one spayed bitch with a vaginal neoplasm. Urinalyses in 11 affected bitches with prolapse or vaginal or urethral neoplasia were normal, and bacterial culture of urine revealed no growth in samples from one bitch with a prolapse, two with vaginal neoplasia, and two with urethral neoplasia. One bitch with vaginal neoplasia showed growth of hemolytic Escherichia coli from urine collected by catheterization. Surgical Pathology Exfoliative cytologic evaluation of excised masses was not reliable in the diagnosis of a fibroleiomyoma and a carcinoma but did accurately identify a transmissible venereal tumor, a carcinoma, and a lipoma when compared with histopathology findings . Leiomyomas (6) and fibroleiomyomas (5) comprised the most common vaginal tumors in this study, and the transitional cell carcinoma was the most common urethral tumor (3 of 5). DIAGNOSTIC APPROACH TO VAGINALNESTIBULAR MASSES Collection of Pertinent Hisory Vaginal/vestibular masses in bitches younger than two years of age usually are vaginal prolapses; in middle-aged bitches, such masses may be vaginal or urethral neoplasia. There is no breed predisposition to vaginal/ vestibular neoplasia, but large-breed bitches tend to have greater risk of vaginal prolapse than other breeds. 20 Both intact and.spayed female dogs may have vaginal/vestibular neoplasia; prolapse usually occurs in the intact bitch at the time of estradiol secretion or at the end of diestrus, and prolapse recurrence can be prevented by ovariohysterectomy. Presenting
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clinical signs may include the owner's observation of a protruding mass, vulvar discharge, vulvar swelling, dysuria, polyuria, or pollakiuria. History should include duration and progression (neoplasia) or regression (prolapse) of the mass. Physical Examination General physical examination, inspection, vaginal/vestibular palpation, and rectal palpation of the mass should be -performed. The site of origin, color, size, and consistency of the mass should be recorded. The urinary bladder should be palpated per abdomen, and straining to urinate should be noted if present. Peripheral lymph nodes should be palpated for evidence of enlargement. A vaginal cytology specimen should be collected, stained, and examined to characterize the stage of the estrous cycle in the intact bitch, the character of the vulvar discharge, if any, and the nature of any exfoliated (potentially malignant) cells from the mass. 34 • 35 Abnormal epithelium observed on vaginal smears from an older bitch with a palpable vaginal mass, dysuria, or hematuria is suggestive of neoplasia. 26 Vaginoscopy may aid in localizing the site and extent of the mass, and biopsy often can be performed through the vaginoscope. Vaginoscopic observation of small tumors may not be possible if the tumors are obscured by vaginal folds. 26 Other Diagnostic Methods Measurement of serum progesterone and estradiol may confirm the stage of the estrous cycle in the bitch with a vaginal mass and may indicate that the bitch with vaginal prolapse is in the follicular phase, offering the treatment option of inducing ovulation with gonadotropin releasing hormone. 36 Measurement of endogenous plasma adrenocorticotropic hormone and plasma cortisol after dexamethasone suppression is indicated in bitches with clitoral enlargement and other signs of hyperadrenalcorticism . Examination of urine sediment may reveal the presence of neoplastic cells in patients with urinary bladder or urethral neoplasia, although this method does not localize tumor site further and does not rule out neoplasia if the urine sediment is normal. Survey abdominal radiography and retrograde vaginography or urethrocystography after visual inspection of the mass at vaginoscopy may be used to characterize the size and extent of vaginal/vestibular tumors and should be incorporated as part of the routine diagnostic plan . Survey thoracic radiographs should be included in the radiographic workup of middle-aged and older patients in which neoplasia is a differential diagnosis. Ultrasonography of the mass, if possible, can provide information on its texture and presence of cysts or abscesses. Exfoliative cytologic evaluation of the mass is helpful in the diagnosis of transmissible venereal tumors and some urethral neoplasms that protrude into the vagina. 19 • 49 Excision biopsy of masses in middle-aged to older spayed bitches and bitches in anestrus is indicated for both diagnosis and treatment. Young bitches with masses that increase during estrus or late diestrus , in which vaginal prolapse is the most likely diagnosis, may be monitored for regression of the mass before considering excision.
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SUMMARY The most common causes of vaginal/vestibular masses in the bitch are vaginal prolapse, vaginal neoplasia, and urethral neoplasia protruding into the vaginal vault. Other possible causes are clitoral enlargement, vaginal polyps, uterine prolapse, and vaginal abscessation or hematoma. Vaginal prolapse usually can be distinguished from neoplasia by the age of the patient, the time of occurrence during the estrous cycle, and the site of origin of the mass. Prolapse usually occurs in bitches under 4 years of age during proestrus, estrus, or at the end of diestrus and usually arises from the floor of the vagina, except for urethral tumors that protrude from the external urethral orifice. Appropriate diagnostic workup of bitches with vaginal vestibular masses includes complete history and physical examination, vaginal cytologic and vaginoscopic examination, retrograde vaginography or urethrocystography, serum progesterone and estradiol concentrations, and, in the case of suspect neoplasms, surgical or excision biopsy of the mass.
REFERENCES l. Alexander JE, Lennox WJ: Vaginal prolapse in a bitch. Can Vet J 2:428-430, 1961 2. Amber EI, Henderson RA: Canine transmissible venereal tumor: Evaluation of surgical excision of primary and metastatic lesions in Zaria Nigeria. JAm Vet Med Assoc 18:350352, 1982 3. Banks WJ: Comparative organology. In Applied Veterinary Histology, ed 2. Baltimore, Williams and Wilkins, 1986, p 514 4. Barrett RE, Theilen GH: Neoplasms of the canine and feline reproductive tracts. In Kirk RW (ed): Current Veterinary Therarapy VI: Small Animal Practice. Philadelphia, WB Saunders, 1977, pp 1263-1267 5. Blakely CL: Prolapse of the vagina. In Kirk RW (ed): Current Veterinary Therapy II: Small Animal Practice. Philadelphia, WB Saunders, 1966, pp 421-422 6. Brodey RS, Roszel JF: Neoplasms of the canine uterus, vagina and vulva: A clinicopathologic survey of 90 cases. JAm Vet Med Assoc 151:1294-1307, 1967 7. Brown NO, Clay C, MacEwen EG: Chemotherapeutic management of transmissible venereal tumor in 30 dogs. JAm Vet Med Assoc 176:983, 1980 8. Burke TJ, Reynold HA: The female genital system. In Bojarb MJ (ed): Pathophysiology in Small Animal Surgery. Philadelphia, Lea & Febiger, 1981, p 425 9. Cotchin E: Neoplasms in the dog. Vet Rec 66:879-884, 1954 10. Davies JV, Read HM: Urethral tumors in dogs. J Small Anim Pract 31:131-136, 1990 11. French A, Obwolo M, Hill FWG: Vaginal prolapse associated with ascites in a pregnant bitch. Zimbabwe Vet J 18:66-68, 1987 12. Greiner TP, Zolton GM : Genital emergencies. In Morrow DA (ed): Current Therapy in Theriogenology. Philadelphia, WB Saunders, 1980, pp 617-618 13. Hare WCD: Intersexuality in the dog. Can Vet J 17:7-15, 1976 14. Herron MA: Tumors of the canine genital system. J Am Anim Hosp Assoc 19:981-994, 1983 15. Higgins DA: Observations on the canine transmissible venereal tumor as seen in the Bahamas. Vet Rec 79:67-71, 1966 16. Hulland TJ: Tumors of the muscle. In Moulton JE (ed): Tumors in Domestic Animals, ed 3. Berkeley, University of California Press, 1990, p 90 17. Iroghli B: Canine transmissible venereal tumors in Iran. Vet Pathol14:289-290, 1977 18. Johnson CA: Uterine disease. In Ettinger SJ (ed): Textbook of Veterinary Internal Medicine, ed 2, vol 2. Philadelphia, WB Saunders, 1989, pp 1801-1802
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19. Johnson CA: Vaginal disorders. In Ettinger SJ (ed): Textbook of Veterinary Internal Medicine, ed 2, vol 2. Philadelphia, WB Saunders, 1989, pp 1809-1811 20. Johnston SD: Vaginal prolapse. In Kirk RW (ed): Current Veterinary Therapy X. Philadelphia, WB Saunders, 1989, pp 1302-1305 21. Jones DE, Joshua JO: Vaginal vestibule and vulva. In Reproductive Clinical Problems in the Dog. Bristol, Wright PSG, 1982, pp 24-25 22. Jubb KVF, Kennedy PC, Palmer NX: The urinary system. In Jubb KVF, Kennedy PC, Palmer NX (eds): Pathology of Domestic Animals, ed 3, vol 2. New York, Academic Press, 1985, pp 398-400 23. Jubb KVF, Kennedy PC, Palmer NX: The female g~nital system. In Jubb KVF, Kennedy PC, Palmer NX (eds): Pathology of Domestic Animals, ed 3, vol3. New York, Academic Press, 1985, pp 374-376 24. Kydd DM, Burnie AG: Vaginal neoplasia in the bitch: a review of 40 clinical cases. J Small Anim Pract 27:255-263, 1986 25. Madewell BR, Theilen GH: Tumors of the urogenital tract. In Theilen GH, Madewell BR (eds): Veterinary Cancer Medicine. Philadelphia, Lea & Febiger, 1987, pp 590-591 26. Magne ML, Hoopes PJ, Kainer RA, et al: Urinary tract carcinoma involving the canine vagina and vestibule. JAm Vet Med Assoc 21:767-772, 1985 27. Maxie MG : The urinary system. In Jubb KVF, Kennedy PC, Palmer NX (eds): Pathology of Domestic Animals, ed three, vol two. Orlando, Academic Press, 1985, pp 398-400 28. Milks HJ: Some diseases of the genito-urinary system. Cornell Vet 29:105-114, 1939 29. Morgan RV: Urogenital emergencies: Part 2. Compend Contin Educ Pract Vet 5:43-53, 1983 30. Murry M, James ZH, Martin WB: A study of the cytology and karyotype of the canine transmissible venereal tumor. Res Vet Sci 10:565-568, 1969 31. Newman MH: Prolapse of the uterus in the bitch and the cat [Letter]. Vet Rec 73:680, 1961 32. Nielsen SW, Kennedy PC: Tumors of the genital system . In Moulton JE (ed): Tumors in Domestic Animals, ed 3. Berkeley, University of California Press, 1990, pp 498-502 33. Oduye 00, Ikede BO, Esuruoso GO, et al: Metastatic transmissible venereal tumor in dogs. J Small Anim Pract 14:625_:637, 1973 34. Olson PN, Thrall MA, Wykes PM, et al: Vaginal cytology: Part 1: A useful tool in staging the canine estrous cycle. Comp Contin Educ Pract Vet 6:288-297, 1984 35. Olson PN, Thrall MA, Wykes PM, et al: Vaginal cytology: Part II: A useful tool for diagnosing reproductive disorders. Comp Contin Educ Pract Vet 6:385-390, 1984 36. Pineda MH: Reproductive pattern of dogs. In McDonald LE, Pineda MH (~ds) : Veterinary Endocrinology and Reproduction, ed 4. Philadelphia, Lea & Febiger, 1989, p 466 37. Richardson RC: Canine transmissible venereal tumor. Comp Contin Educ Pract Vet 3:951-956, 1981 38. Robert SJ: Injuries and diseases of the puerperal period. In Woodstock, Veterinary Obstetrics and Genital Diseases (Theriogenology). Woodstock, Vermont, Published by the author, 1986, p 365 39. Sahay PN, Dass LL, Khan AA, et al: Urinary incontinence in a bitch caused by vaginal fibroma. Vet Rec 116:76-77, 1985 40. Schneider R: Epidemiological aspects of mammary and genital neoplasia. In Morrow DA (ed): Current Therapy in Theriogenology. Philadelphia, WB Saunders, 1980, pp 636639 41. Schutte AP: Vaginal prolapse in the bitch. J South Afr Vet Med Assoc 38:197-203, 1967 42. Soderberg SF: Vaginal disorders. Vet Clin North Am Small Anim Pract 16:543-559, 1986 43. Stone EA: The uterus. In Slatter DH (ed): Textbook of Small Animal Surgery. Philadelphia, WB Saunders, 1985, pp 1661-1671 44. Tarvin G, Patnaik A, Greene R: Primary urethral tumors in dogs. J Am Vet Med Assoc 172:931, 1978 45. Thacher C, Bradley RL: Vulvar and vaginal tumors in the dog: A retrospective study. J Am Vet Med Assoc 183:690-692, 1983 46. Troger CP: Vaginal prolapse in the bitch. Mod Vet Prac 51:38-41, 1970 47. Weller RE, Park JF: Vaginal leiomyoma and polyps in a Beagle dog. Calif Vet 37:6-7, 1983 48. Wilson GP, Hayes HM Jr, Casey HW: Canine urethral cancer. JAm Anim Hosp Assoc 15:741, 1978
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49. Withrow SJ, Susaneck SJ: Tumors of the canine female reproductive tract. In Morrow DA (ed): Current Therapy in Theriogenology 2. Philadelphia, WB Saunders, 1986, pp 526-527 50. Wood DS: Canine uterine prolapse. In Morrow DA (ed): Current Therapy in Theriogenology 2. Philadelphia, WB Saunders, 1986, p 510 51. World Health Organization: Report of the Second Consultation of the Biological Behavior and Therapy of Tumors of Domestic Animals. Geneva, WHO, 1979, pp 18-20 52. Wykes PM: Diseases of the vagina and vulva in the bitch. In Morrow DA (ed): Current Therapy in Theriogenology 2. Philadelphia, WB Saunders, 1986, pp 478-480 53. Wykes PM , Olson PN: The vulva. In Slatter DH (ed): T-extbook of Small Animal Surgery. Philadelphia, WB Saunders, 1985, pp 1678-1680
Address reprint requests to Shirley D. Johnston, DVM, PhD Department of Small Animal Clinical Sciences University of Minnesota College of Veterinary Medicine 1352 Boyd Avenue St. Paul, MN 55108
0195-5616/91 $0.00 + .20
Clinical Approach to Vaginal/ Vestibular Masses in the Bitch
Krongthong Manothaiudom, DVM,* and Shirley D. johnston, DVM , PhDt
Vaginal/vestibular masses in the bitch may involve the vestibule, the vagina, the urethral orifice, or a combination of these structures. Bitches with vaginal/vestibular masses may show abnormal clinical signs of the reproductive or urinary system or may be asymptomatic. Neoplastic masses may metastasize to other reproductive organs or to other organs of the abdomen and the thorax. Misdiagnosis of vaginal/vestibular masses leads to ineffective treatment and wasted time and money and can be harmful to the patient. The purpose of this article is to review the causes of vaginal/ vestibular masses reported in the bitch, present a survey of 44 cases of such masses identified retrospectively at the University of Minnesota Veterinary Teaching Hospitals, and describe a suggested method of clinical evaluation of dogs with these masses in a practice setting. CAUSES OF VAGINALNESTIBULAR MASSES Vaginal/vestibular masses may occur in both intact and spayed bitches of any age and in individual bitches of any breed. Types of vaginal/vestibular masses in the dog include vaginal prolapses, vaginal neoplasia, urethral neoplasia, and less common nonneoplastic masses such as uterine prolapse, clitoral hypertrophy, vaginal polyps, vaginal abscessation, or hematomas. Vaginal Prolapse Vaginal prolapse (vaginal hyperplasia, vaginal hypertrophy, estrual hypertrophy, vaginal eversion, vaginal protrusion) is characterized by marked edema of the submucosa and stratified squamous epithelium lining From the University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota *Department of Clinical and Population Sciences tDiplomate, American College ofTheriogenologists; Associate Professor, Department of Small Animal Clinical Sciences Veterinary Clinics of North America: Small Animal Practice-Vol. 21 , No. 3, May 1991
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the vaginal lumen, resulting in prolapse of a dome-shaped or doughnutshaped mass of tissue into the vaginal vault and through the vulvar cleft. 20 • 41 It occurs mainly in young, intact, large-breed dogs in proestrus or estrus and occasionally occurs during pregnancy or at parturition, when it interferes with normal delivery. 5• 11 • 20• 29 • 42• 46 • 52 The degree of vaginal tissue protrusion can be classified into three types. 41 Type l is slight to moderate eversion of the vaginal floor cranial to the external urethral orifice; the everted tissue does not protrude through the vulva. Type 2 is complete prolapse through the vulva of a broad, tongue-shaped mass with a narrow base or a dome-shaped mass; both originate on the floor of the cranial vagina. 20 • 42 Type 3 is complete prolapse of the entire circumference of the vaginal wall, which presents a dougnut-shaped or ring-shaped mass. 41 · 42· 46 The mean age of 65 affected dogs was 2 years , and ages ranged from 7 months to 11 years. 20 This disorder has been reported in a number of breeds and may be seen in certain families of purebred dogs, suggesting a hereditary breed predisposition. 8• 20· 41 • 46 Presenting signs of vaginal prolapse include the presence of a mass protuding through the vulva, licking at the mass, difficulty in urinating, and failure to achieve normal mating. 20 The protruding mass appears as a pink, pear-shaped, smooth, tumor-like structure. 28 • 29 Vaginal prolapse may be an emergency if prolapsed tissue is dry, traumatized, and necrotic or if the pressure of the mass leads to concurrent dysuria or oliguria. 12· 29 The minimum data base required for patients with vaginal prolapse are history, physical examination findings, and vaginal smears in young bitches. Older bitches require vaginal mass biopsy to distinguish vaginal prolapse from neoplasia. Laboratory findings in the hemogram, clinical chemistry profile, and reproductive hormone assays (estradiol or progesterone) of affected bitches are within normal limits. 20 • 36 Spontaneous regression of vaginal prolapse occurs after estrus or following parturition. 12• 20 • 41 • 42 The recurrence rate of vaginal prolapse in affected bitches is estimated to exceed 66%. 20 Treatment of vaginal prolapse in the bitch can be attempted by several methods depending on the breeding future of the affected bitch. These include conservative treatment by topical lubrication with use of an Elizabethan collar and induction of ovulation in the bitch in the follicular phase with gonadotropin releasing hormone (2.2 j.t.g/kg intramuscularly) to shorten the time of estradiol release before ovulation. Excision of the prolapsed tissue in late estrus or early diestrus may be considered in bitches intended for future breeding. 20 Permanent prevention of vaginal prolapse is by ovariohysterectomy. 1• 12• 20· 42 Vaginal Neoplasia Vaginal neoplasia is the second most common reproductive neoplasm in the bitch after neoplasms of the mammary gland and usually occurs in the older bitch. 6 · 9 · 35 The most common canine vaginal tumors are leiomyomas and transmissible venereal tumors. 4 · 6 • 40 • 45 • 47 Mean age of occurrence of vaginal neoplasia in the bitch is about 10 years. 4• 45 The most common clinical signs of vaginal neoplasia in the bitch are the presence of a mass protruding through the vulva and the presence of
CLINICAL APPROACH TO V AGINAUVESTIBULAR MASSES IN THE BITCH
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vaginal discharge. 14• 24 · 28 • 44 • 46• 48 Less commonly, vaginal tumors may cause mechanical interference with surrounding structures when they become large, resulting in stranguria, tenesmus, dysuria, urinary incontinence, or perineal swelling. 19• 39· 45· 47· 49 Diagnosis is based on history and vaginoscopic and physical findings ; exfoliative vaginal cytologic evaluation may be of value with some tumors.34 · 35 Definitive diagnosis is determined by surgical pathology. The treatment of benign vaginal tumors is surgical excision. 19 The leiomyoma may occur as a solitary ()r multiple extraluminal or intraluminal mass. 16• 23· 25 Extraluminal leiomyomas usually arise in the roof of the vestibule, causing bulging of the perineum . Intraluminalleiomyomas usually arise from the vestibular wall and protude from the vulva. 25 They may grow to be 10 to 12 em in diameter. The transmissible venereal tumor tends to be common in areas where dogs are free roaming, and the disease is rare where dogs are controlled. 23 The mode of transmission is by mating or mucous membrane contact with the tumor. 23 These tumors usually originate from the submucosa of the dorsal vaginal wall, in the posterior vagina at the junction of the vestibule and vagina, and, sometimes, at the external urethral orifice. 23 · 32 The size ranges from 0.5 mm to over 10 em in diameter. 15· 17• 30• 33 This tumor is a solitary or multiple, cauliflower-like mass, which is friable and commonly ulcerated. 23 • 32 · 37 Metastasis is uncommon but may occur to regional lymph nodes. 23 • 32 Spontaneous regression occasionally occurs without treatment. 5 • 7 • 23 The tumor responds to a variety of modes of treatment such as surgical removal, radiation, and chemotherapy. Recurrence after surgical excision may occur. Canine vaginal tumors are staged according to behavior of the primary tumor (T), regional lymph node (inguinal, internal iliac, sacral) involvement (N), and evidence of distant metastasis. 51 Because stages, progression, and prognosis of malignant vaginal tumors have not been reported together, staging data are now used to completely characterize tumor extent rather than to predict tumor behavior. Urethral Neoplasia
Canine urethral tumors can be categorized into two types on the basis of tissue origin: Epithelial tumors, such as carcinomas, and mesenchymal tumors, such as leiomyomas. Most tumors of the urethra are malignant, and metastatic urethral tumors are rare. 27 They are more common in female than male dogs. 10 In one report, seven of seven affected bitches were spayed, 26 and in another, 8 of 19 bitches were spayed. 10· 26 The size of affected dogs tends to be small to medium (10-25 kg) . 10 These tumors occur in old dogs ranging from 10 to 12 years. 26 The mean age is 10.2 years. 10 Transitional cell carcinomas and squamous cell carcinomas are common in the distal urethra of the bitch. 44 • 48 The histologic appearance of these tumors may be similar at the time of neoplastic cell replication. 3· 22 • 44 Urinary tract carcinomas can involve the vagina, vestibule, or both. The most common clinical signs are stranguria, hematuria, and hematocolpos. 26 The most common clinical sign of bladder involvement is dysuria. 10 Digital examination of the vagina and vaginoscopy are the most helpful and rapid methods for presumptive diagnosis of urethral neoplasia in the
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bitch. Cytologic examination of urine sediment is a useful tool but is diagnostic in only 40% of cases. 44 Definitive diagnosis of neoplasia is made by histologic evaluation of biopsy tissue. 35 Unfortunately, urethral tumors usually are not diagnosed until an advanced stage. 26 Other Nonneoplastic Vaginal/Vestibular Masses
Uterine prolapse occurs infrequently in the dog but may occur just before or after parturition. Primiparous and ·multiparous bitches may be affected. 31 The cervix, one uterine horn, or both horns can prolapse partially or completely. 38• 50 The prolapse usually occurs after delivery of the last fetus. 18 Clinical signs include vaginal discharge, abdominal pain, straining, restlessness, and protrusion of the mass from the vulva. 50 Diagnosis is made on the basis of the bitch's history of pregnancy and parturition and the appearance of the mass. Treatment depends on the animal's physical condition. If the animal and the uterus are healthy, manual reduction can be done. If not, excision of the uterus and reduction of the stump should be performed. 43 Clitoral enlargement can occur in bitches and in male pseudohermaphrodites. 13 Administration of exogenous androgens or anabolic steroids may lead to clitoral hypertrophy and the presence of an os clitoridis in the bitch. If the bitch is given androgens during pregnancy, clitoral enlargement may be seen in female puppies. Some bitches with hyperadrenocorticoidism also have been reported to show an enlarged clitoris. 42 • 53 Clitoritis and vaginitis may result from irritation of the enlarged clitoris protuding through the vulvar cleft. Affected bitches frequently lick the vulva. Diagnosis is based on history, inspection of the clitoris at the vulva, and measurement of endogenous adrenocorticotropic hormone or results of a dexamethasone suppression test. Treatment includes topical antibiotic ointment to relieve irritation and inflammation, removal of the androgen source, or excision of the enlarged clitoris. The clitoris regresses to normal size when the exogenous androgen is withdrawn. If an os is present, clitoral enlargement may persist. 42 Vaginal polyps (fibropapillomas) are common in aging bitches. They occur during the later part of the estrous cycle as small, occasionally ulcerated nodules, with variable hemorrhage. Treatment of choice is surgical removal. Recurrence is rare. 21
A RETROSPECTIVE SURVEY OF 44 CASES OF VAGINAU VESTIBULAR MASSES IN THE BITCH Material and Methods Data in this study were obtained from 44 case records of bitches with vaginal/vestibular masses seen at the Veterinary Teaching Hospital, University of Minnesota, between 1981 and 1990. Vaginal masses seen included vaginal prolapse (18), clitoral enlargement (1), benign vaginal neoplasia (14-6 leiomyoma, 5 fibroleiomyoma, 1 fibroma, 1 transmissible venereal tumor, and 1 lipoma), malignant vaginal neoplasia (6, 3 carcinoma, 1
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adenocarcinoma, 1 squamous cell carcinoma, and 1 leiomyosarcoma), and malignant urethral neoplasia (5, 3 transitional cell carcinoma, 1 melanoma, and 1 transitional cell carcinoma and fibrosarcoma). Signalment, presenting complaints, history, physical examination, and laboratory findings (vaginal cytologic evaluation, vaginoscopy, hormone assay, clinical chemistry, hematology, ultrasonography, radiology, urinalysis, gross pathology, and histopathology) were tabulated and categorized retrospectively. Signalment Vaginal/vestibular masses were present in bitches of different ages, breeds, and sizes (Tables 1 and 2), and in both intact and spayed bitches. The age of bitches with vaginal prolapse ranged from 7 months to 16 years; the majority of masses were present in intact bitches (16/18) under 4 years (11/18) of large breeds (11/18). The single bitch with clitoral enlargement was 6 years old and was a small-breed spayed female . Vaginal tumors were present in bitches from 4 to 15 years of age (mean, 11 years), and there was no breed predisposition. Thirteen of the twenty bitches with vaginal tumors were intact. Benign vaginal tumors tended to occur in small-breed (6/12) rather than medium- (3/12) or large-breed (3/12) animals. Malignant vaginal tumors occured in large-breed bitches (4/8) more than in medium(2/8), small-breed (118), or giant-breed (118) bitches. Urethral tumors Table 1. Age Distribution of 44 Bitches with Vaginal/Vestibular Masses DIAGNOSIS
AGE (YEARS)
0.7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Unknown
Vaginal Prolapse
Clitoral Enlargement
Neoplasia Vaginal
1 4 3 1 2 2
Urethral
1* 1*
lt 1* 1* 1t, 1* 2t 2t, 1* 2t 3t, 1* 2t
1
1
1 1
Range
0.7-16
6
Mean
4.6
6
Total
17
4-15
6-12
11
8.6
20
5
* = malignant neoplasm; t = benign neoplasm.
TOTAL
1 4 3 1 3 3 3 3 2 0 3 3 4 3 4 2 1 1
44
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Table 2. Breed Distribution of 44 Bitches with Vaginal/Vestibular Masses NEOPLASIA
(0--20 lb) Miniature Poodle Poodle Pekingese Chihuahua Cockapoo Chihuahua/Terrier Lhasa Apso/Poodle Pekingese/Poodle Total (11)
VAGINAL
CLITORAL
PROLAPSE
ENLARGEMENT
Vaginal! Vestibular
Urethral
SMALL BREEDS
MEDIUM BREEDS (21-50 lb) Australian Shepherd Beagle English Springer Spaniel Scottish Terrier Smooth Coat Collie German Shepherd Cocker Spaniel/Poodle Mixed Terrier Puli Total (12)
(51-100 lb) Labrador Retriever Golden Retriever German Shepherd Collie Shepherd/Retriever St. Bernard Mixed St. Bernard Old English Sheepdog Weimaranner Dobermann Pinscher Irish Setter Australian Shepherd Walker Hound Total (18)
1t 1
lt 1t 1t 1t
lt, * 1t 2
7
1* 1t 1* 1t 1t 1 1 5
5
2
LARGE BREEDS
GIANT BREEDS(> 100
Boxer Mastiff Golden Retriever Total (3)
1
1* 1t 1t 1 1*
1 3 1
1* 1* 1*
1 1 9
7
2
lb) 1,*t 2
* = malignant neoplasm; t = benign neoplasm, * = transmissible tumor.
protruding into the vagina as masses occurred in one intact and four spayed bitches from 6 to 12 years old, with no size predisposition. History The most common historical complaint was presence of a prolapsing vaginal mass (Table 3). This sign was found in dogs with vaginal prolapse, vaginal neoplasia, and urethral neoplasia. Other major clinical signs were
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presence of a vaginal discharge, dysuria, and increased frequency of urination (pollakiuria). Estrous bitches were represented only in the vaginal prolapse group (five bitches). Signs referrable to the genital system were the most frequently reported (Table 3); 3 of the 44 bitches had no historical problems identified in the history. The duration of the vaginal mass in the bitch with clitoral enlargement and in 12 of the 20 bitches with vaginal neoplasia prior to presentation was reported to be more than 1 week. Duration of vaginal prolapse prior to presentation varied from 1 day (1118), to 1 day to 1 week (3/18), to more than 1 week (3/18), and was not reported in 11 of the 18 patients. Mass progression was reported in 1 of 18 bitches with vaginal prolapse, 4 of 20 bitches with vaginal neoplasia, and 1 of 5 bitches with urethral neoplasia. Mass regression were reported in 3 of 18 bitches with vaginal prolapse and in 1 of 20 bitches with vaginal neoplasia. Previous treatments of the vaginal mass included ovariohysterectomy, vaginal mass excision, cauterization, purse-string suture at the vulvar cleft, application of an Elizabethan collar, and topical antibiotics. One vaginal prolapse and two vaginal tumors recurred after ovariohysterectomy, and one vaginal prolapse and two vaginal tumors recurred after vaginal mass excision. Physical Examination Findings Abnormal physical examination findings of the urinary system in bitches with vaginal masses included presence of a large urinary bladder and Table 3. Clinical Signs in 44 Bitches with Vaginal/Vestibular Masses VAGINAL
CLITORAL
PROLAPSE
ENLARGEMENT
(N = 18)
(N = 11)
NEOPLASIA
Vaginal/Vestibular (N = 20)
Urethral (N = 5)
TOTAL
10 3
6 6 1
1 1
4
5
1
1
1
2 3
17 11 1 11 3 5
GENITAL
Vaginal prolapse Vaginal mass/lump Vaginal ulceration Vulvar discharge Vulvar bleeding Licking at the vulva Vulvar swelling
4
1
5
3
3 1
1 4 2 2
2 13
URINARY
Hematuria Inappropriate urination Polyuria Dysuria Pollakiuria Nocturia Could not urinate
4
1 1 1
1 5 4
7 4
1
GASTROINTESTINAL
Vomiting Diarrhea Straining Anorexia
2
1
1 3 4
1 1 1
3 2 5 4
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D. JOHNSTON
presence of a mass protuding from urethra. In the genital system, the most common finding was the presence of vaginal tissue prolapsed through the vulvar cleft (l0/18 cases of prolapse and 6/20 cases of vaginal neoplasia). The next most common findings were the presence of vaginal thickening, the presence of an intravaginal mass, vulvar swelling (5/18 cases of prolapse, 1120 cases of vaginal neoplasia, and 115 cases of urethral neoplasia), presence of a mammary nodule (2/18 cases of prolapse and 3/20 cases of vaginal neoplasia) and presence of vulvar discharge (mucopurulent in one case each with vaginal and urethral neoplasia; sanguinous in one case each of prolapse and vaginal neoplasia, and serous in one case each of prolapse and vaginal neoplasia). Less common findings were mammary gland enlargement in the bitch with the enlarged clitoris, inguinal hernia, hypoplastic vulva, perivulvar tissue distention, perineal bulging, perineal dermatitis and infection, and vaginal hyperemia. Lymph node enlargement was present in the inguinal node in one bitch with a prolapse and in the popliteal nodes of one bitch with prolapse and one bitch with vaginal neoplasia. Various other unrelated abnormalities were reported for the musculoskeletal system, eye, skin, ear, heart, mouth, and respiratory system of various affected bitches. The vaginal/vestibular masses were red (6/18 prolapses, 2/20 vaginal tumors, 115 urethral tumors), pink (3/18 prolapses), red with blackened portions (2/10 vaginal tumors), white and black (1120 vaginal tumors), and white (1120 vaginal masses). The size of the vaginal masses of 13 bitches ranged from 2 em to 16 em in diameter. Two transmissible tumors in a bitch were 2 and 5 em in diameter. The size of prolapsed vaginal tissue in six bitches ranged from 1 em to 7.5 em in diameter. The size of the urethral tumors in three bitches ranged from 1 em to 3 em in diameter. The shapes of the vaginal/vestibular masses were variable, including an elongated vaginal prolapse mass, a stalked vaginal prolapse mass, a spherical vaginal tumor, an irregular urethral tumor, and a conical urethral tumor. Masses were movable (one prolapse, two vaginal neoplasms), pedunculated (two vaginal neoplasms), nodular (one vaginal neoplasm), ulcerated/eroded (one prolapse, one vaginal neoplasm), necrotic (one prolapse), and/or smooth (three prolapses). Consistency of the masses was recorded as firm in one prolapse and four vaginal neoplasms and firm with some soft areas in one vaginal neoplasm. Vaginal smears of affected bitches showed cytologic evidence of proestrus in two bitches with prolapse, estrus in three bitches with prolapse and one bitch with a vaginal neoplasm, and diestrus in three bitches with prolapse and two bitches with vaginal neoplasms. Vaginoscopy The sites of origin of masses observed vaginoscopically were recorded as ventral vagina (one prolapse and one vaginal neoplasm), vaginal mucosa surrounding the external urethral orifice (one urethral neoplasm), vaginal mucosa cranial to the external urethral orifice (one vaginal neoplasm), and urethral tissue protruding into the vagina from the external urethral orifice (one urethral neoplasm).
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Radiology and Ultrasonography Survey caudal abdominal, perineal, and thoracic radiographs, ultrasonograms of the vaginal mass, and retrograde vaginograms, urethrograms, cystourethrograms, and radiographs after barium enemas were taken of some of the animals with vaginal masses. The descending colon was displaced in one bitch with a vaginal neoplasm and in one bitch with a urethral neoplasm. A mass was demonstrated in the urinary bladder of a bitch with a vaginal neoplasm, and the urinary bladder was distended in another. Vaginal and uterine masses were detected radiographically or ultrasonographically in three bitches with vaginal neoplasia. The lungs appeared radiographically normal in six bitches with vaginal neoplasia and two bitches with urethral neoplasia and showed evidence of metastatic disease in one of the bitches with vaginal tumors. Other Laboratory Findings Blood samples were collected from 28 of the affected bitches for routine hemograms and from 25 bitches for routine chemistry profiles; no abnormalities were noted in any of the samples. Serum progesterone concentrations in three bitches with prolapses were more than 2 ng/mL, indicating that they were in the luteal phase of their cycles. Serum estradiol and progesterone concentrations were undetectable in one spayed bitch with a vaginal neoplasm. Urinalyses in 11 affected bitches with prolapse or vaginal or urethral neoplasia were normal, and bacterial culture of urine revealed no growth in samples from one bitch with a prolapse, two with vaginal neoplasia, and two with urethral neoplasia. One bitch with vaginal neoplasia showed growth of hemolytic Escherichia coli from urine collected by catheterization. Surgical Pathology Exfoliative cytologic evaluation of excised masses was not reliable in the diagnosis of a fibroleiomyoma and a carcinoma but did accurately identify a transmissible venereal tumor, a carcinoma, and a lipoma when compared with histopathology findings . Leiomyomas (6) and fibroleiomyomas (5) comprised the most common vaginal tumors in this study, and the transitional cell carcinoma was the most common urethral tumor (3 of 5). DIAGNOSTIC APPROACH TO VAGINALNESTIBULAR MASSES Collection of Pertinent Hisory Vaginal/vestibular masses in bitches younger than two years of age usually are vaginal prolapses; in middle-aged bitches, such masses may be vaginal or urethral neoplasia. There is no breed predisposition to vaginal/ vestibular neoplasia, but large-breed bitches tend to have greater risk of vaginal prolapse than other breeds. 20 Both intact and.spayed female dogs may have vaginal/vestibular neoplasia; prolapse usually occurs in the intact bitch at the time of estradiol secretion or at the end of diestrus, and prolapse recurrence can be prevented by ovariohysterectomy. Presenting
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clinical signs may include the owner's observation of a protruding mass, vulvar discharge, vulvar swelling, dysuria, polyuria, or pollakiuria. History should include duration and progression (neoplasia) or regression (prolapse) of the mass. Physical Examination General physical examination, inspection, vaginal/vestibular palpation, and rectal palpation of the mass should be -performed. The site of origin, color, size, and consistency of the mass should be recorded. The urinary bladder should be palpated per abdomen, and straining to urinate should be noted if present. Peripheral lymph nodes should be palpated for evidence of enlargement. A vaginal cytology specimen should be collected, stained, and examined to characterize the stage of the estrous cycle in the intact bitch, the character of the vulvar discharge, if any, and the nature of any exfoliated (potentially malignant) cells from the mass. 34 • 35 Abnormal epithelium observed on vaginal smears from an older bitch with a palpable vaginal mass, dysuria, or hematuria is suggestive of neoplasia. 26 Vaginoscopy may aid in localizing the site and extent of the mass, and biopsy often can be performed through the vaginoscope. Vaginoscopic observation of small tumors may not be possible if the tumors are obscured by vaginal folds. 26 Other Diagnostic Methods Measurement of serum progesterone and estradiol may confirm the stage of the estrous cycle in the bitch with a vaginal mass and may indicate that the bitch with vaginal prolapse is in the follicular phase, offering the treatment option of inducing ovulation with gonadotropin releasing hormone. 36 Measurement of endogenous plasma adrenocorticotropic hormone and plasma cortisol after dexamethasone suppression is indicated in bitches with clitoral enlargement and other signs of hyperadrenalcorticism . Examination of urine sediment may reveal the presence of neoplastic cells in patients with urinary bladder or urethral neoplasia, although this method does not localize tumor site further and does not rule out neoplasia if the urine sediment is normal. Survey abdominal radiography and retrograde vaginography or urethrocystography after visual inspection of the mass at vaginoscopy may be used to characterize the size and extent of vaginal/vestibular tumors and should be incorporated as part of the routine diagnostic plan . Survey thoracic radiographs should be included in the radiographic workup of middle-aged and older patients in which neoplasia is a differential diagnosis. Ultrasonography of the mass, if possible, can provide information on its texture and presence of cysts or abscesses. Exfoliative cytologic evaluation of the mass is helpful in the diagnosis of transmissible venereal tumors and some urethral neoplasms that protrude into the vagina. 19 • 49 Excision biopsy of masses in middle-aged to older spayed bitches and bitches in anestrus is indicated for both diagnosis and treatment. Young bitches with masses that increase during estrus or late diestrus , in which vaginal prolapse is the most likely diagnosis, may be monitored for regression of the mass before considering excision.
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SUMMARY The most common causes of vaginal/vestibular masses in the bitch are vaginal prolapse, vaginal neoplasia, and urethral neoplasia protruding into the vaginal vault. Other possible causes are clitoral enlargement, vaginal polyps, uterine prolapse, and vaginal abscessation or hematoma. Vaginal prolapse usually can be distinguished from neoplasia by the age of the patient, the time of occurrence during the estrous cycle, and the site of origin of the mass. Prolapse usually occurs in bitches under 4 years of age during proestrus, estrus, or at the end of diestrus and usually arises from the floor of the vagina, except for urethral tumors that protrude from the external urethral orifice. Appropriate diagnostic workup of bitches with vaginal vestibular masses includes complete history and physical examination, vaginal cytologic and vaginoscopic examination, retrograde vaginography or urethrocystography, serum progesterone and estradiol concentrations, and, in the case of suspect neoplasms, surgical or excision biopsy of the mass.
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49. Withrow SJ, Susaneck SJ: Tumors of the canine female reproductive tract. In Morrow DA (ed): Current Therapy in Theriogenology 2. Philadelphia, WB Saunders, 1986, pp 526-527 50. Wood DS: Canine uterine prolapse. In Morrow DA (ed): Current Therapy in Theriogenology 2. Philadelphia, WB Saunders, 1986, p 510 51. World Health Organization: Report of the Second Consultation of the Biological Behavior and Therapy of Tumors of Domestic Animals. Geneva, WHO, 1979, pp 18-20 52. Wykes PM: Diseases of the vagina and vulva in the bitch. In Morrow DA (ed): Current Therapy in Theriogenology 2. Philadelphia, WB Saunders, 1986, pp 478-480 53. Wykes PM , Olson PN: The vulva. In Slatter DH (ed): T-extbook of Small Animal Surgery. Philadelphia, WB Saunders, 1985, pp 1678-1680
Address reprint requests to Shirley D. Johnston, DVM, PhD Department of Small Animal Clinical Sciences University of Minnesota College of Veterinary Medicine 1352 Boyd Avenue St. Paul, MN 55108
