ULTRASONIC CHARACTERISTICS OF PELVIC INFLAMMATORY MASSES by Philip C. Uhrich, MD*; and Roger C. Sanders, BM**
ABSTRACT Twenty patients with pelvic abscesses diagnosed either at surgery o r from typical clinical findings underwent sonography. Seventeen of the twenty patients had inflammatory processes of gynecological origin. In the main, t w o patterns were observed. The more common pattern was a small, round adnexal o r cul de sac mass with a slightly irregular border. The other pattern consisted of large, rough-bordered, multilocular masses that obscured the uterus. In single cases confusion had occurred between pelvic abscesses, fibroids, and chronic ruptured tuba1 pregnancy. The role of ultrasound in the management of patients with tubo-ovarian abscesses is discussed.
Indexing Words Pelvic Abscess Tubo-Ovarian Abscess Chronic Ruptured Tuba1 Pregnancy
Several previous publications (1, 2, 4 ) have referred t o the ultrasonic findings in patients with pelvic inflammatory disease. These descriptions occurred in reviews of the applications of ultrasound in the diagnosis of pelvic masses. The experience at Johns Hopkins in the diagnosis by ultrasound of tubo-ovarian abscesses (TOA), pelvic abscesses, and pelvic inflammatory masses was reviewed to try t o determine whether there are specific ultrasonic patterns for these conditions. Although this was a retrospective study, an attempt was made to find all cases which had been referred t o the ultrasonic laboratory with a pre-examination diagnosis of tubo-ovarian abscess or pelvic inflammatory disease. Some helpful ultrasonic patterns were found but several other entities were encountered which can produce similar findings. Both will be described below. METHOD
Standard contact B scanning techniques were used ( 3 ) and images obtained through a collimated 2.25 MHz transducer were recorded either on Polaroid film or as hard copies. LongiFrom the *Ultrasound Department, St. Paul’s Hospital, Vancouver, British Columbis; and **The Johns Hopkins Medical Institutions, Baltimore, Maryland. Received April 21, 1975;revision accepted January 14,1976. For reprints contact: Philip C. Uhrich. MD, St. Paul’s Hospital, Vancouver, British Columbia. VOLUME 4. NUMBER 3
Diagnostic Ultrasound Abdominal Abscess
tudinal and transverse scans of the pelvic area were routinely obtained at 1 cm intervals. A mode techniques were used to differentiate cystic from solid masses but Polaroid photographs of the results were not always recorded. Unless unable to cooperate, patients were examined with their bladders full. The charts and sonograms of patients with known or suspected peloic inflammatory masses were reviewed retrospectively. Included in the series are patients in whom there was surgcal proof of a tubo-ovarian or pelvic abscess or in whom such a diagnosis was extremely likely based on the typical findings of fever, tenderness in the pelvic area, a palpable pelvic mass, and the disappearance or decrease in size of a mass after appropriate antibiotic therapy. This review does not include all patients with palpable tubo-ovarian abscesses seen at Johns Hopkins since a few of the charts were mislaid, negative examinations were not reviewed, and patients with inconclusive clinical findings were excluded. The sonograms were classified with respect t o the size, shape, outline, multiplicity, and internal structure of the masses seen. The ability t o outline the uterus as a separate structure was noted. Wall irregularity was graded on a scale of I-IV with Grade I being totally irregular, Grade I1 moderately irregular, Grade I11 slightly irregular, and Grade IV smooth-walled 199
18
3A 38 FIGURE 3. A ) transverse and 6)longitudinal section of Case 19 showing well-defined right adnexal mass which responded t o antibiotic therapy. The uterus i s not seen because it i s medial t o section 36 and inferior t o section 3A.
1c
1D 6 = bladder; A = abscess; U = uterus. FIGURE 1. A ) Longitudinal section of a pelvic abscess (Case 2) showing a grossly irregular wall, Grade I. 6) Another pelvic abscess showing a moderately irregular wall, Grade II (Case 3). C) A third mass, a tubo-ovarian abscess (Case 14). showing a D) A n Ovarian cyst w i t h a slightly irregular wall, Grade 111. smooth wall, Grade IV.
~~
.
~~
~
2A 28 FIGURE 2. A ) transverse and B) longitudinal sections of Case 3 showing a large multilocular midline mass in a patient w i t h bilateral tubo-ovarian abscesses. Notice t h e uterus is incorporated int o the mass.
(Fig. 1). Not all cases fitted neatly into this scheme since in a small minority of cases one portion of the wall was rough and another portion was smooth. RESULTS
The clinical history, surgical results, pathological reports, and sonographic findings are tabulated in Table I. The age range in the 20 patients examined, all of whom were female, was 6 to 45 with a mean age of 23.6. Seventeen of the 20 patients had an inflammatory process of proven or presumed gynecological origin. In the remaining three patients abscesses resulted from a ruptured appendix, Crohn’s disease, and pelvic lymphadenitis. Surgical proof was available in 1 4 of the 20 patients. Eleven cases had surgery within two weeks of the diagnosis; in three (Nos. 4, 9 and 15) there was a six- t o eight-week delay. Seventeen of the 20 patients had definite palpable masses. In two cases (Nos. 8 and 15) 200
48 4A FIGURE 4. A ) transverse and 6) longitudinal sections of a right adnexal mass (Case 10) showing small fluid collections adjacent t o mass ( f ) .
5A 58 FIGURE 5. A ) longitudinal and 6)transverse sections of a cystic cul d e sac mass which resolved w i t h antibiotics (Case 20).
radiological evidence of a mass was the indication for a sonogram. A clinically questionable mass (No. 13) was confirmed by the use of sonography. In another patient (No. 14), a mass thought to be a fibroid on the basis of the palpation was shown by ultrasound to be cystic and therefore not a fibroid. Masses varied in size from 2 0 x 1 5 ~ 1 2cm to 4 . 5 ~ 3cm. The ultrasonic appearance of the abscesses can be subdivided into two main groups. A common pattern is a large, roughbordered, multilocular mass that obscures the uterus (Fig. 2). A second recurring pattern is a smaller, round or oval, adnexal or cul de sac mass with a less irregular border that does not obscure the uterus (Fig. 3). Seventeen of the patients showed single or bilateral adnexal masses. In two, the masses were small, separate, sonolucent areas adjacent to the predominant mass (Fig. 4).There were ten instances of purely cystic lesions without internal echoes (Fig. 5). In six cases there were septa or linear echoes within JOURNAL O F CLINICAL ULTRASOUND
6A 6B FlGURE 6. A) Transverse and B ) longitudinal sections of a patient with a proven tubo-ovarian abscess showing a welldefined septum. The uterus is incorporated into the mass (Case 141.
cystic masses (Fig. 6), and in three further cases there were a few internal echoes within otherwise cystic lesions. One patient was felt to have a complex lesion with septa. DISCUSSION
One previous study of ultrasound in the diagnosis of pelvic masses claimed a high degree of accuracy in diagnosing TOA-18 of 18 cases (1) but the diagnostic criteria used were not described. Morley and Barnett (2) state that TOA’s are hard to differentiate from ovarian cysts but do not comment on wall irregularity in their group of pelvic abscesses. They concluded in their 12 cases that ultrasound was of value primarily in the followup. In this series the accuracy rate in differentiating cystic masses from solid, homogeneous lesions was approximately 95 percent. No overall accuracy figures can be given since it is conceivable, though unlikely, that a sonogram may have failed t o reveal an inflammatory mass that subsided spontaneously. In one case a fibroid was misdiagnosed as a tubo-ovarian abscess. In other cases, TOA was mentioned first in a long list of possible explanations for a cystic appearance in the pelvis. Clinical findings a t the time of the examination helped in differentiating between the different diagnostic possibilities. From this series it would appear that TOA and pelvic abscesses have the following ultrasonic patterns. In the earlier stages there is a single cystic structure with irregular walls. In pelvic abscesses this cystic structure is located in the midline in the cul de sac posterior t o the uterus and in TOA it is located in the region of the adnexa on either side of the uterus. Frequently the inflammatory process spreads and secondary cystic areas, presumably small abscesses, develop. Eventually a large multilocular mass appears. This mass may appear t o incorporate the uterus and may be as large as 25 cm in diameter. VOLUME 4, NUMBER 3
7A
7B
7c 7D FIGURE 7 . A ) Longitudinal section of a malignant ovarian cyst ( 0 )showing slight irregular wall margin. B l Longitudinal section of a fibroid ( C ) thought to be a pelvic abscess. C) Longitudinal section of bladder, uterus and endometrial cyst (C) in the cul de D) ‘Midline longitudinal section of a chronic ruptured sac. ectopic pregnancy ( E ) .
As a general rule it can be stated that pelvic inflammatory masses have irregular walls, and although they may possess septa, are classifiable ultrasonically as cystic. A single example of a complex pelvic abscess was seen; presumably multiple small abscess locules were present. In one gas-filled midabdominal abscess not included in this series, the typical ultrasonic features of a cyst were not seen because gas does not conduct ultrasound, although a mass could be seen in the region of the abscess. Most pelvic or tubo-ovarian abscesses were unilateral. With bilateral TOA’s a confluent pelvic mass is often seen on ultrasound, though a single example of separate, bilateral TOA’s was seen (No. 11).The wall irregularities seen in inflammatory disease are presumably related t o exudates and adhesions involving pelvic structures. An inability t o outline the uterus or a discrete abscess in large midline inflammatory masses is a commonplace finding and would support this contention. A similar difficulty was encountered in the case of pelvic abscess secondary to Crohn’s disease. Inflamed loops of bowel are known t o produce transonic areas probably because of the widening of the bowel wall due t o inflammation and the enlargement of adjacent lymph nodes. Because of the limited number of patterns which can be produced by echo reflections and the similarity in the gross pathology of many of the entities that cause pelvic masses, it is not surprising that other processes can mimic the ultrasonic appearance of TOA or pelvic abscess. 201
TABLE I Patient Age
SONOGRAM Uterus Internal Border O u t l i n e Structures
Clinical Data
Surgery
Pathology
Size
Shape
Lower abdominal pain and vaginal discharge. Massive bilateral adnexal masses.
Subacute w i t h bilateral TOAs
(L) T O A .
9x9x9 cm
Lobular; single
I
No
Cystic w i t h Midpelvis f e w internal echoes
2 ) BC 2 5
Pain, fever, tender 6 c m ( L ) mass
Scheduled f o r surgery b u t never returned
15 x 1Ox9
Amorphous; multiIocu lar
I
No
Complex w i t h septa
Lower abdominal and pelvis
3) C D 20
L L Q pain and fever w i t h tender l e f t adnexal mass
Chronic bilateral pyosalpinges
Subacute inflammation and necrosis compatible w i t h bilateral TOA
II
No
Cystic w i t h septa
Midpelvis
41 JW 1 8
Pain, fever, 1 4 wk. size mass i n cul de sac
T w o mos. later rupture o f TOA with peritonitis
(L)T O A 1 4 x 14x16.5 R o u n d (R) acute and w i t h flatchronic tened anterior surface; single
I1
No
Cystic w i t h multiple seata
Midpelvis
5) MS 45
Pain and constipation. R L Q mass and mass i n cul de sac
Mvomatous uterus w i t h large bilatera1 T O A s and several large peritoneal inclusion cysts
Mvomata6 x . 5 ~ 3c m 3 x 1 ~ 1c m 3 x 2 ~ c1 m bilateral TOA
Ill
Yes, b u t no1 clearly
Cystic w i t h Midpelvis linear inter- extending nal echoes t o (L)
6 ) M C 28
R L Q pain, tender 12-14 c m ( R ) adnexal mass
Bilateral severe P I D with (R) adnexal mass
Bilateral 8x9~12 chronic adhesive perisalpingitis and periooporitis w i t h hydrosalpinges
Round; multiple
Ill
No
Cystic
Cul de sac and ( R ) adnexal
7 ) D F 25
Lower abdominal pain and fever; palpable grapef r u i t size mass, tender. K n o w n Crohn’s disease w i t h enteric fistulae
200-300 cc pelvic abscess drained
9x6~6
Round; single with surrounding locules
II
Yes
Cystic
Cul de sac
8) LLJ 6
( L ) h i p pain w i t h fever and limp. Mass o n (L)displacing bladder o n IVP.
Pelvic abscess and obturator lymphadenitis; abscess drained.
4.5x3
Ova I ; single
Not Cystic atwith tempted internal echoes
( L ) adnexal
9) K B 27
Pain, fever ( L ) 10-18 c m tender mass which decreased i n size
6 wks. later multiple adhesions about ovaries and tubes
Multilocular; multiple
Yes
Cystic w i t h septum
( L ) adnexal
Round; single with separate locules
Yes
Cystic
(R) adnexal w i t h locules in cul de sac
1 ) C W 22
10) A H 1 8 Pain and fever
(R) chronic adhesive perisal ping it i s
2 0 x 1 6 ~ 1 2 Multilocular; multiple
1 1 ~ 1 0 x 1 2 Round; single
(L)chronic 6x6 cm adhesive peri- and ooporitis and 7.5x7.5 chronic salpingitis 6x6~6
( R ) adnexal mass which disappeared after therapy
Some processes that produce pelvic masses can be clearly distinguished. Ovarian cysts and cystic teratoma have smooth walls and may or may not show septa. The smoothness of the walls should 202
Location
make confusion with TOA or pelvic abscess unlikely. In one recent malignant ovarian cyst, a slightly irregular wall (Grade 111) was seen; gross pathological examination revealed multiple J O U R N A L O F CLINICAL U L T R A S O U N D
SONOGRAM
Patient
Age
Clinical Data
Surgery
Pathology
Size
Shape
Border
Internal Structures
Location
Reported solid; cystic in retrospect
Bilateral adnexal
Yes
Cystic
Cul de sac
Ill
Yes
Cystic
Cul d e sac
11) LL 20 Amenorrhea x 4 months w i t h o u t evidence o f pregnancy. Bilateral adnexal cystic masses pa Ipa b le.
Laparoscopy B ila teral hydrosal p i nx
6 x 6 ~ c6m (L) 6 x 4 ~ c4m (R)
Round; single o n each side
1 2 ) SS 3 2
Lower abdominal pain and fever; developed a mass i n cul de sac
Drainage o f pelvic abscess
1o x 9 x 9
Round; single
Ill
13) T E 3 5 One day history o f rectal and vaginal pain w i t h fever; question o f mass i n cul de sac
Ruptured appendix w i t h 300-400 cc well walled o f f abscess
7.5x4.5
Round; single
OW 3 3
Uterus Outline
( L )T O A
(L) TOA 6 x 8 ~ 1 0c m
11x11~8
Round; single
Ill
No
Cystic with a septum
Midline
( L ) Tuboovarian inflammatory mass removed.
Chronic sal pinqitis and adh’ksive perisal p i ng it i s. Chronic and acute oophoritis
1 1x 8 x 8
Multilocular; single
Ill
Yes
Cystic w i t h linear internal echoes
( L ) adnexal
5x5x2.5
Oval; single
Ill
Partially Cystic (fundus)
( R ) adnexal
1 7 ) D B 1 9 Fever, R L Q pain and vaginal discharge. 5 c m ( R ) adnexal mass which decreased i n size after antibiotics.
5x5x2.5
Oval €9 lobu lated single bilateral
Ill
Yes
Cystic w i t h internal echoes
Bilateral adnexal
1 8 ) L H 2 3 R L Q pain, fever. Had 10+ c m mass o n (R); disappeared after treatment.
7.5x3x4.5
Sausage shaped; single
Ill
Yes
Cvstic
( R ) adnexal
1 9 ) PS
Pain, fever. 1 0 c m tender cul de sac mass w h i c h disappeared.
6x6~6
Round; single
Ill
Yes
Cvstic
( R ) adnexal
20) BS 29
Pain, fever and palpable mass (transient)
4.5x4.5 x4.5
Round; single
Ill
Yes
Cystic
Cul de sac
14)
Presented w i t h symptoms o f urinary infection; asymptomat ic after antibiotics. 1 8 w k . size mass palpable.
15) C A 16 Persistent draining sinus o n b u t t o c k . Found t o extend i n t o pelvis; adnexal f u I Iness.
16) L A 1 8 Pain, fever ( R ) adnexal mass palpable; disappeared after treatment,
excresences with a granular appearance (Fig. 7A). Fibroids, when echofree, show poor through transmission. A portion of the fibroid is always contiguous with the uterus except when it arises from an ovary. These ultrasonic characteristics make confusion with TOA unlikely but in a single case in this series in which the clinical and ultrasonic characteristics suggested a cystic mass, a fibroid was wrongly diagnosed as a pelvic abscess (Fig. 7B). VOLUME 4, NUMBER 3
Endometriosis and multiple small cysts show the greatest ultrasonic similarity to pelvic inflammatory disease (Fig. 7C) since they may also show multiple cystic lesions of varying size with possible incorporation of the uterus into the mass. On the other hand, many endometrial cysts are smooth-walled structures in the pelvis. Another important differential diagnosis that should be considered is a chronic ruptured ectopic pregnancy. Again, there is a large, midline, multicystic mass lying behind the uterus 203
(Fig. 7D). Ovarian tumors such as the SteinLevinthal syndrome should not be confused with TOA’s since the mass, though echofree, does not show good through transmission and has the appearance of a solid, homogeneous mass. Ultrasound has a limited but important role to play in the clinical management of pelvic inflammatory disease and tubo-ovarian abscesses. When the clinical presentation is confusing, ultrasound will confirm or disprove the presence of a pelvic mass. An idea of the pathological nature of a pelvic mass will be gained from the ultrasonic appearance. Surgical management of pelvic inflammatory disease is helped by ultrasonic anatomical localization since an easy distinction can be made between a unilocular and a multilocular abscess from the ultrasonic examination. If the abscess is predominantly unilocular and presents itself as a fluctuant mass dissecting the rectovaginal septum, drainage through the vagina may be therapeutically effective. Conversely, if it is multilocular with the loculations at some distance from the vaginal incision, vaginal drainage may not be entirely effective, and antibiotic treatment may be more appropri-
204
ate. Response to antibiotic therapy can be assessed by ultrasound. Since pelvic abscesses are exquisitely tender, assessment of size by palpation may be limited, but followup ultrasonic examinations are easy to perform, provided the site of the ultrasonic section is marked in a fashion that can be reliably repeated. It is also quite important to make the distinction between TOA and pelvic abscess if drainage from below is considered. The pelvic abscess may have small and large bowel as part of its wall. Manipulation and instrumentation could easily lead to disruption of the abscess wall and leakage into the peritoneal cavity. 1. 2.
3. 4.
REFERENCES Cochrane WJ and Thomas MA: Ultrasound diagnosis of gynecologic pelvic masses. Radiology 110: 649, 1974. Morley P and Barnett E: The use of ultrasound in the diagnosis of pelvic masses. Br J Radio1 43: 602, 1970. Bearman S, Sanders RC, and Oh KS: B-scan ultrasound in the evaluation of pediatric abdominal masses. Radiology 108: 111, 1973. Thompson HE, Holmes JH, Gottesfeld KR, and Taylor ES: Ultrasound as a diagnostic aid in diseases of the pelvis. Am J Obstet Gynecol98: 472,1967.
JOURNAL O F CLINICAL ULTRASOUND
ABSTRACT Twenty patients with pelvic abscesses diagnosed either at surgery o r from typical clinical findings underwent sonography. Seventeen of the twenty patients had inflammatory processes of gynecological origin. In the main, t w o patterns were observed. The more common pattern was a small, round adnexal o r cul de sac mass with a slightly irregular border. The other pattern consisted of large, rough-bordered, multilocular masses that obscured the uterus. In single cases confusion had occurred between pelvic abscesses, fibroids, and chronic ruptured tuba1 pregnancy. The role of ultrasound in the management of patients with tubo-ovarian abscesses is discussed.
Indexing Words Pelvic Abscess Tubo-Ovarian Abscess Chronic Ruptured Tuba1 Pregnancy
Several previous publications (1, 2, 4 ) have referred t o the ultrasonic findings in patients with pelvic inflammatory disease. These descriptions occurred in reviews of the applications of ultrasound in the diagnosis of pelvic masses. The experience at Johns Hopkins in the diagnosis by ultrasound of tubo-ovarian abscesses (TOA), pelvic abscesses, and pelvic inflammatory masses was reviewed to try t o determine whether there are specific ultrasonic patterns for these conditions. Although this was a retrospective study, an attempt was made to find all cases which had been referred t o the ultrasonic laboratory with a pre-examination diagnosis of tubo-ovarian abscess or pelvic inflammatory disease. Some helpful ultrasonic patterns were found but several other entities were encountered which can produce similar findings. Both will be described below. METHOD
Standard contact B scanning techniques were used ( 3 ) and images obtained through a collimated 2.25 MHz transducer were recorded either on Polaroid film or as hard copies. LongiFrom the *Ultrasound Department, St. Paul’s Hospital, Vancouver, British Columbis; and **The Johns Hopkins Medical Institutions, Baltimore, Maryland. Received April 21, 1975;revision accepted January 14,1976. For reprints contact: Philip C. Uhrich. MD, St. Paul’s Hospital, Vancouver, British Columbia. VOLUME 4. NUMBER 3
Diagnostic Ultrasound Abdominal Abscess
tudinal and transverse scans of the pelvic area were routinely obtained at 1 cm intervals. A mode techniques were used to differentiate cystic from solid masses but Polaroid photographs of the results were not always recorded. Unless unable to cooperate, patients were examined with their bladders full. The charts and sonograms of patients with known or suspected peloic inflammatory masses were reviewed retrospectively. Included in the series are patients in whom there was surgcal proof of a tubo-ovarian or pelvic abscess or in whom such a diagnosis was extremely likely based on the typical findings of fever, tenderness in the pelvic area, a palpable pelvic mass, and the disappearance or decrease in size of a mass after appropriate antibiotic therapy. This review does not include all patients with palpable tubo-ovarian abscesses seen at Johns Hopkins since a few of the charts were mislaid, negative examinations were not reviewed, and patients with inconclusive clinical findings were excluded. The sonograms were classified with respect t o the size, shape, outline, multiplicity, and internal structure of the masses seen. The ability t o outline the uterus as a separate structure was noted. Wall irregularity was graded on a scale of I-IV with Grade I being totally irregular, Grade I1 moderately irregular, Grade I11 slightly irregular, and Grade IV smooth-walled 199
18
3A 38 FIGURE 3. A ) transverse and 6)longitudinal section of Case 19 showing well-defined right adnexal mass which responded t o antibiotic therapy. The uterus i s not seen because it i s medial t o section 36 and inferior t o section 3A.
1c
1D 6 = bladder; A = abscess; U = uterus. FIGURE 1. A ) Longitudinal section of a pelvic abscess (Case 2) showing a grossly irregular wall, Grade I. 6) Another pelvic abscess showing a moderately irregular wall, Grade II (Case 3). C) A third mass, a tubo-ovarian abscess (Case 14). showing a D) A n Ovarian cyst w i t h a slightly irregular wall, Grade 111. smooth wall, Grade IV.
~~
.
~~
~
2A 28 FIGURE 2. A ) transverse and B) longitudinal sections of Case 3 showing a large multilocular midline mass in a patient w i t h bilateral tubo-ovarian abscesses. Notice t h e uterus is incorporated int o the mass.
(Fig. 1). Not all cases fitted neatly into this scheme since in a small minority of cases one portion of the wall was rough and another portion was smooth. RESULTS
The clinical history, surgical results, pathological reports, and sonographic findings are tabulated in Table I. The age range in the 20 patients examined, all of whom were female, was 6 to 45 with a mean age of 23.6. Seventeen of the 20 patients had an inflammatory process of proven or presumed gynecological origin. In the remaining three patients abscesses resulted from a ruptured appendix, Crohn’s disease, and pelvic lymphadenitis. Surgical proof was available in 1 4 of the 20 patients. Eleven cases had surgery within two weeks of the diagnosis; in three (Nos. 4, 9 and 15) there was a six- t o eight-week delay. Seventeen of the 20 patients had definite palpable masses. In two cases (Nos. 8 and 15) 200
48 4A FIGURE 4. A ) transverse and 6) longitudinal sections of a right adnexal mass (Case 10) showing small fluid collections adjacent t o mass ( f ) .
5A 58 FIGURE 5. A ) longitudinal and 6)transverse sections of a cystic cul d e sac mass which resolved w i t h antibiotics (Case 20).
radiological evidence of a mass was the indication for a sonogram. A clinically questionable mass (No. 13) was confirmed by the use of sonography. In another patient (No. 14), a mass thought to be a fibroid on the basis of the palpation was shown by ultrasound to be cystic and therefore not a fibroid. Masses varied in size from 2 0 x 1 5 ~ 1 2cm to 4 . 5 ~ 3cm. The ultrasonic appearance of the abscesses can be subdivided into two main groups. A common pattern is a large, roughbordered, multilocular mass that obscures the uterus (Fig. 2). A second recurring pattern is a smaller, round or oval, adnexal or cul de sac mass with a less irregular border that does not obscure the uterus (Fig. 3). Seventeen of the patients showed single or bilateral adnexal masses. In two, the masses were small, separate, sonolucent areas adjacent to the predominant mass (Fig. 4).There were ten instances of purely cystic lesions without internal echoes (Fig. 5). In six cases there were septa or linear echoes within JOURNAL O F CLINICAL ULTRASOUND
6A 6B FlGURE 6. A) Transverse and B ) longitudinal sections of a patient with a proven tubo-ovarian abscess showing a welldefined septum. The uterus is incorporated into the mass (Case 141.
cystic masses (Fig. 6), and in three further cases there were a few internal echoes within otherwise cystic lesions. One patient was felt to have a complex lesion with septa. DISCUSSION
One previous study of ultrasound in the diagnosis of pelvic masses claimed a high degree of accuracy in diagnosing TOA-18 of 18 cases (1) but the diagnostic criteria used were not described. Morley and Barnett (2) state that TOA’s are hard to differentiate from ovarian cysts but do not comment on wall irregularity in their group of pelvic abscesses. They concluded in their 12 cases that ultrasound was of value primarily in the followup. In this series the accuracy rate in differentiating cystic masses from solid, homogeneous lesions was approximately 95 percent. No overall accuracy figures can be given since it is conceivable, though unlikely, that a sonogram may have failed t o reveal an inflammatory mass that subsided spontaneously. In one case a fibroid was misdiagnosed as a tubo-ovarian abscess. In other cases, TOA was mentioned first in a long list of possible explanations for a cystic appearance in the pelvis. Clinical findings a t the time of the examination helped in differentiating between the different diagnostic possibilities. From this series it would appear that TOA and pelvic abscesses have the following ultrasonic patterns. In the earlier stages there is a single cystic structure with irregular walls. In pelvic abscesses this cystic structure is located in the midline in the cul de sac posterior t o the uterus and in TOA it is located in the region of the adnexa on either side of the uterus. Frequently the inflammatory process spreads and secondary cystic areas, presumably small abscesses, develop. Eventually a large multilocular mass appears. This mass may appear t o incorporate the uterus and may be as large as 25 cm in diameter. VOLUME 4, NUMBER 3
7A
7B
7c 7D FIGURE 7 . A ) Longitudinal section of a malignant ovarian cyst ( 0 )showing slight irregular wall margin. B l Longitudinal section of a fibroid ( C ) thought to be a pelvic abscess. C) Longitudinal section of bladder, uterus and endometrial cyst (C) in the cul de D) ‘Midline longitudinal section of a chronic ruptured sac. ectopic pregnancy ( E ) .
As a general rule it can be stated that pelvic inflammatory masses have irregular walls, and although they may possess septa, are classifiable ultrasonically as cystic. A single example of a complex pelvic abscess was seen; presumably multiple small abscess locules were present. In one gas-filled midabdominal abscess not included in this series, the typical ultrasonic features of a cyst were not seen because gas does not conduct ultrasound, although a mass could be seen in the region of the abscess. Most pelvic or tubo-ovarian abscesses were unilateral. With bilateral TOA’s a confluent pelvic mass is often seen on ultrasound, though a single example of separate, bilateral TOA’s was seen (No. 11).The wall irregularities seen in inflammatory disease are presumably related t o exudates and adhesions involving pelvic structures. An inability t o outline the uterus or a discrete abscess in large midline inflammatory masses is a commonplace finding and would support this contention. A similar difficulty was encountered in the case of pelvic abscess secondary to Crohn’s disease. Inflamed loops of bowel are known t o produce transonic areas probably because of the widening of the bowel wall due t o inflammation and the enlargement of adjacent lymph nodes. Because of the limited number of patterns which can be produced by echo reflections and the similarity in the gross pathology of many of the entities that cause pelvic masses, it is not surprising that other processes can mimic the ultrasonic appearance of TOA or pelvic abscess. 201
TABLE I Patient Age
SONOGRAM Uterus Internal Border O u t l i n e Structures
Clinical Data
Surgery
Pathology
Size
Shape
Lower abdominal pain and vaginal discharge. Massive bilateral adnexal masses.
Subacute w i t h bilateral TOAs
(L) T O A .
9x9x9 cm
Lobular; single
I
No
Cystic w i t h Midpelvis f e w internal echoes
2 ) BC 2 5
Pain, fever, tender 6 c m ( L ) mass
Scheduled f o r surgery b u t never returned
15 x 1Ox9
Amorphous; multiIocu lar
I
No
Complex w i t h septa
Lower abdominal and pelvis
3) C D 20
L L Q pain and fever w i t h tender l e f t adnexal mass
Chronic bilateral pyosalpinges
Subacute inflammation and necrosis compatible w i t h bilateral TOA
II
No
Cystic w i t h septa
Midpelvis
41 JW 1 8
Pain, fever, 1 4 wk. size mass i n cul de sac
T w o mos. later rupture o f TOA with peritonitis
(L)T O A 1 4 x 14x16.5 R o u n d (R) acute and w i t h flatchronic tened anterior surface; single
I1
No
Cystic w i t h multiple seata
Midpelvis
5) MS 45
Pain and constipation. R L Q mass and mass i n cul de sac
Mvomatous uterus w i t h large bilatera1 T O A s and several large peritoneal inclusion cysts
Mvomata6 x . 5 ~ 3c m 3 x 1 ~ 1c m 3 x 2 ~ c1 m bilateral TOA
Ill
Yes, b u t no1 clearly
Cystic w i t h Midpelvis linear inter- extending nal echoes t o (L)
6 ) M C 28
R L Q pain, tender 12-14 c m ( R ) adnexal mass
Bilateral severe P I D with (R) adnexal mass
Bilateral 8x9~12 chronic adhesive perisalpingitis and periooporitis w i t h hydrosalpinges
Round; multiple
Ill
No
Cystic
Cul de sac and ( R ) adnexal
7 ) D F 25
Lower abdominal pain and fever; palpable grapef r u i t size mass, tender. K n o w n Crohn’s disease w i t h enteric fistulae
200-300 cc pelvic abscess drained
9x6~6
Round; single with surrounding locules
II
Yes
Cystic
Cul de sac
8) LLJ 6
( L ) h i p pain w i t h fever and limp. Mass o n (L)displacing bladder o n IVP.
Pelvic abscess and obturator lymphadenitis; abscess drained.
4.5x3
Ova I ; single
Not Cystic atwith tempted internal echoes
( L ) adnexal
9) K B 27
Pain, fever ( L ) 10-18 c m tender mass which decreased i n size
6 wks. later multiple adhesions about ovaries and tubes
Multilocular; multiple
Yes
Cystic w i t h septum
( L ) adnexal
Round; single with separate locules
Yes
Cystic
(R) adnexal w i t h locules in cul de sac
1 ) C W 22
10) A H 1 8 Pain and fever
(R) chronic adhesive perisal ping it i s
2 0 x 1 6 ~ 1 2 Multilocular; multiple
1 1 ~ 1 0 x 1 2 Round; single
(L)chronic 6x6 cm adhesive peri- and ooporitis and 7.5x7.5 chronic salpingitis 6x6~6
( R ) adnexal mass which disappeared after therapy
Some processes that produce pelvic masses can be clearly distinguished. Ovarian cysts and cystic teratoma have smooth walls and may or may not show septa. The smoothness of the walls should 202
Location
make confusion with TOA or pelvic abscess unlikely. In one recent malignant ovarian cyst, a slightly irregular wall (Grade 111) was seen; gross pathological examination revealed multiple J O U R N A L O F CLINICAL U L T R A S O U N D
SONOGRAM
Patient
Age
Clinical Data
Surgery
Pathology
Size
Shape
Border
Internal Structures
Location
Reported solid; cystic in retrospect
Bilateral adnexal
Yes
Cystic
Cul de sac
Ill
Yes
Cystic
Cul d e sac
11) LL 20 Amenorrhea x 4 months w i t h o u t evidence o f pregnancy. Bilateral adnexal cystic masses pa Ipa b le.
Laparoscopy B ila teral hydrosal p i nx
6 x 6 ~ c6m (L) 6 x 4 ~ c4m (R)
Round; single o n each side
1 2 ) SS 3 2
Lower abdominal pain and fever; developed a mass i n cul de sac
Drainage o f pelvic abscess
1o x 9 x 9
Round; single
Ill
13) T E 3 5 One day history o f rectal and vaginal pain w i t h fever; question o f mass i n cul de sac
Ruptured appendix w i t h 300-400 cc well walled o f f abscess
7.5x4.5
Round; single
OW 3 3
Uterus Outline
( L )T O A
(L) TOA 6 x 8 ~ 1 0c m
11x11~8
Round; single
Ill
No
Cystic with a septum
Midline
( L ) Tuboovarian inflammatory mass removed.
Chronic sal pinqitis and adh’ksive perisal p i ng it i s. Chronic and acute oophoritis
1 1x 8 x 8
Multilocular; single
Ill
Yes
Cystic w i t h linear internal echoes
( L ) adnexal
5x5x2.5
Oval; single
Ill
Partially Cystic (fundus)
( R ) adnexal
1 7 ) D B 1 9 Fever, R L Q pain and vaginal discharge. 5 c m ( R ) adnexal mass which decreased i n size after antibiotics.
5x5x2.5
Oval €9 lobu lated single bilateral
Ill
Yes
Cystic w i t h internal echoes
Bilateral adnexal
1 8 ) L H 2 3 R L Q pain, fever. Had 10+ c m mass o n (R); disappeared after treatment.
7.5x3x4.5
Sausage shaped; single
Ill
Yes
Cvstic
( R ) adnexal
1 9 ) PS
Pain, fever. 1 0 c m tender cul de sac mass w h i c h disappeared.
6x6~6
Round; single
Ill
Yes
Cvstic
( R ) adnexal
20) BS 29
Pain, fever and palpable mass (transient)
4.5x4.5 x4.5
Round; single
Ill
Yes
Cystic
Cul de sac
14)
Presented w i t h symptoms o f urinary infection; asymptomat ic after antibiotics. 1 8 w k . size mass palpable.
15) C A 16 Persistent draining sinus o n b u t t o c k . Found t o extend i n t o pelvis; adnexal f u I Iness.
16) L A 1 8 Pain, fever ( R ) adnexal mass palpable; disappeared after treatment,
excresences with a granular appearance (Fig. 7A). Fibroids, when echofree, show poor through transmission. A portion of the fibroid is always contiguous with the uterus except when it arises from an ovary. These ultrasonic characteristics make confusion with TOA unlikely but in a single case in this series in which the clinical and ultrasonic characteristics suggested a cystic mass, a fibroid was wrongly diagnosed as a pelvic abscess (Fig. 7B). VOLUME 4, NUMBER 3
Endometriosis and multiple small cysts show the greatest ultrasonic similarity to pelvic inflammatory disease (Fig. 7C) since they may also show multiple cystic lesions of varying size with possible incorporation of the uterus into the mass. On the other hand, many endometrial cysts are smooth-walled structures in the pelvis. Another important differential diagnosis that should be considered is a chronic ruptured ectopic pregnancy. Again, there is a large, midline, multicystic mass lying behind the uterus 203
(Fig. 7D). Ovarian tumors such as the SteinLevinthal syndrome should not be confused with TOA’s since the mass, though echofree, does not show good through transmission and has the appearance of a solid, homogeneous mass. Ultrasound has a limited but important role to play in the clinical management of pelvic inflammatory disease and tubo-ovarian abscesses. When the clinical presentation is confusing, ultrasound will confirm or disprove the presence of a pelvic mass. An idea of the pathological nature of a pelvic mass will be gained from the ultrasonic appearance. Surgical management of pelvic inflammatory disease is helped by ultrasonic anatomical localization since an easy distinction can be made between a unilocular and a multilocular abscess from the ultrasonic examination. If the abscess is predominantly unilocular and presents itself as a fluctuant mass dissecting the rectovaginal septum, drainage through the vagina may be therapeutically effective. Conversely, if it is multilocular with the loculations at some distance from the vaginal incision, vaginal drainage may not be entirely effective, and antibiotic treatment may be more appropri-
204
ate. Response to antibiotic therapy can be assessed by ultrasound. Since pelvic abscesses are exquisitely tender, assessment of size by palpation may be limited, but followup ultrasonic examinations are easy to perform, provided the site of the ultrasonic section is marked in a fashion that can be reliably repeated. It is also quite important to make the distinction between TOA and pelvic abscess if drainage from below is considered. The pelvic abscess may have small and large bowel as part of its wall. Manipulation and instrumentation could easily lead to disruption of the abscess wall and leakage into the peritoneal cavity. 1. 2.
3. 4.
REFERENCES Cochrane WJ and Thomas MA: Ultrasound diagnosis of gynecologic pelvic masses. Radiology 110: 649, 1974. Morley P and Barnett E: The use of ultrasound in the diagnosis of pelvic masses. Br J Radio1 43: 602, 1970. Bearman S, Sanders RC, and Oh KS: B-scan ultrasound in the evaluation of pediatric abdominal masses. Radiology 108: 111, 1973. Thompson HE, Holmes JH, Gottesfeld KR, and Taylor ES: Ultrasound as a diagnostic aid in diseases of the pelvis. Am J Obstet Gynecol98: 472,1967.
JOURNAL O F CLINICAL ULTRASOUND
