J Oral Maxillofac Surg 49:1109-1115,1991

toma tic Posteri STEVEN D. VINCENT, DDS, MS,* S. THOMAS D AND DENNIS h. JOHNSON, DDS, Case Presentation A 54-year-old alert, normally developed white woman, in no acute distress, presented for evaluation of a mildly tender, soft area in the maxillary left tuberosity region of unknown duration. She reported slight mobility of the maxillary left first molar first noticed 4 months previously, without a significant increase in mobility since that time. The second molar had been extracted as a result of unrestorable caries 15 years previously. The third molar had been extracted at age 25. Treatment with penicillin, 500 mg four times daily, prescribed by her dentist 3 weeks before did not result in a significant change in the chief complaint. Current medications included diazepam, 5 mg at bedtime, and an estrogen supplement for occasional postmenopaus,al symptoms. She denied any medication allergies. She reported excision of a lipoma from her back a month ago, and had undergone a hysterectomy 10 years ago for management of multiple uterine leiomyomas. She reported a vague history of recurrent parotitis and had also been treated for asthma as a child. She denied all other central nervous system, respiratory, cardiovascular, genitourinary, gastrointestinal, skin, musculoskeletal, or allergic disease or abnormality, past or present. She reported routine dental care in the past and did not wear upper or lower removable appliances. Extraoral examination showed no significant abnormalities. There were no masses palpated and no restriction of, or pain during, mandibular movements. Gross evaluation of cranial nerves III-XII showed them to be within normal limits. Oral examination showed class II mobility of the maxillary left first molar., No alveolar buccal cortical plate was palpable distal to the tooth. The alveolar mucosa overlying the buccd aspect of the alveolar crest was normal in color, without expansion. The area was asymptomatic to palpation and easily compressible. The distal aspect of the tuberosity seemed to be intact. Pinprick analysis revealed no paresthesia. The distal aspect of the first molar had a bleeding 4- to 5-mm periodontal defect. * Associate Professor, Oral Pathology and Diagnosis, College of Dentistry, University of Iowa, Iowa City. t Senior Resident, Oral Pathology and Diagnosis, College of Dentistry, University of Iowa, Iowa City. j: In private practice, Crystal Lake, IL. Address correspondeke. and reprint’ requests to Dr Vincent: Utiversity of Iowa, CoI@ge of Dentistry, DSB 356, Department of Oral Pathology and Diagnosis, Iowa City, IA 52242. 0 1991 American Association of &al and Maxillofacial geons 0278-2391191I491 O-0014$3.00/O

Sur-

Other than missing and restored teeth, moderate gingivitis, restorations, plaque, and light calculus, no other abnormalities of the intraoral hard or soft tissues were identified. A periapical radiograph of the maxillary left posterior region was submitted by the referring dentist (Fig 1). A panoramic radiograph was made (Fig 2), which showed a large radiolucency and two small radiopacities in the left posterior maxilla.

Dennis 4;. Johnson, DDS, MS According 54year-old symptomatic

to the history, an apparently healthy woman presented with a minimally radiolucency in the left posterior max-

illa. Her only reported symptoms were a shght tenderness and softness in the area, with mobihty of the adjacent first molar. The clinical examination showed a nonexpansile, easily compressible, nontender area of the left posterior maxilla highly suggestive of a cystic lesion, Unfortunately, aspiration apparently was not performed. The normal appearance of the alveolar mucosa and absence of paresthesia suggests a benign process. Evaluation of the panoramic and periapical radiographs shows a poorly defined unilocular radiolucency of the left maxilla with a large (3 x 1.5 cm) dome-shaped mass extending into the maxillary, sinus. A small (5 x 3 mm) radiopaqne mass’ surrounded by a thin radiolucent border is visuahied immediately posterior to the distobuccal root of the maxillary left first molar. This radiopaque laiass resembles the crown of a tooth, ahhough a retained root or other calcified structure must be considered. Theshistory and clinical and radiographic find& suggest a ‘benign odontogenic cyst or tumor, a[? though the poorly defined appearance of the rad$ olucency suggests a more aggressive, possibly ma: lignant, process. To fully establish a d~~fer~nt~~~.d~agnosis, the following categories of &ions shohfd be considered: 1) lesions associated with an in-& pacted su?ernumerary tooth as the etiologic factor; 2) lesions associated with a retained root as the e& ologic factor; 3) mixed radiopaquelradioBucen$~ Id-

IllCl

RADIOLUCENCY

OF THE POSTERIOR MAXliLLA

FIGURE I. A peria&~l ~adiograph of the-left posterior maxilla showing loss_ qf dyeoBar bone, apparent perfo@an of tbe cork9 plate, and two distinct radiopacities

sions; ‘and 4) radiolucent lesions where the small crownlike radiopaque mass would be a coincidental finding. Wadiolucent lesions associated with an impacted supernumerary tooth as the etiologic factor include 1) dentigerous cyst; 2) odontogenic keratocyst (OKC); 3) mural ameloblastoma arising in a dentigerous cyst; 4) ameloblastoma; 5) carcinoma arising in a dentigerous cyst; 6) calcifying epithelial odontogenic tumor (CEOT); 7) calcifying odontogenic

cyst (GorEin cyst); 8) adenomatoid odontogenic tumor; 9) ameloblastic fmroma; and 10) odontogenic myxoma. Radiolucencies associated with a retained tooth root as the etiologic factor include 1) radicular cyst; 2) odontogenic keratocyst (rare); and 3) radicular cyst with carcinomatous changes (rare). Mixed radiopaque-radiolucent lesions include 1) odontoameloblastoma and 2) complex composite odontoma with a dentigerous cyst.

FIGURE 2. A panoramic radiograph made at the initial visit showing a dome-shaped, posterior maxilla and maxillary sinus.

well-defmed,

soft-tissue abnormality of Lbe left

VINCENT’,

DEAML, AND JOHNSON

Radioiucent lesions where the small crownlike radiopaque mass would be a coincidental finding include 1) central squamous cell carcinoma; 2) osteogenic sarcoma (osteolytic type); 3) chondrosarcoma; 4) reticulum cell sarcoma; 5) metastatic lesions; 6) multiple myeloma; 7) fibrQus dysplasia (early stage); 8) ossifying fibroma (early stage); 9) central giant cell granuloma; and 10) carcinoma from maxillary sinus. DePzfigerous cyst. The dentigerous cyst involves the crQwn Qf unerupted teeth, including impacted supernumerary teeth. Although most commonly discovered in the second and third decades, they may be fQund at any age. Although they usually do not, erode the cortical plates of bone, this may occur in some cases, revealing a soft, fluctuant mass on palpation. Paresthesia is rare, mobility of teeth is unco,mmQn, and pain usually indicates the presence Qf infection. Radiographically, it appears as a unilocular radicolucency, often with a thin sclerotic border. Bdontogenic keratocyst. The QKC, which is usually diagnosed between the ages of 20 and 40 years, is more frequent in males than in females. Although the mandible is involved more frequently than the maxilla, OKCs are usually found in the third Imolar area when they Qccur in the maxilla. The 0KC cuts acrcsss the usual classification of cysts bectause a dentigerous cyst, a primordial cyst, or a radicular cyst may prove to be an QKC on microscQpic, examination. The 8KC may present as a unilocnlar. or multilocular radiolueency with a well-defined sclerotic border. They often penetrate bone ?&her than expand it, resulting in a soft, compressible; lesion on palpation. Approximately 50% of patients are symptsmatic prior to diagnosis. Cdontogeni@ keratdscysts are characterized by a high recurrence rate, as much as 60% in some studies. lsllurak ame&o6~~srstom61. Most mural ameloblastomas arise in iaIls of dentigerous cysts, with residual, radicular, globulomaxillary, and primordial cysts less frequently involved. It appears that the potential, to develap ameloblastomatous changes declines significantly after 30 years of age. If left mm-eaten the mural ameloblastoma can develop the invasive’ characteristics of the ameloblastoma. Radiogsaphically, the mural ameloblasfoma may resQrb the sclerotiq border of the dentigerous cyst as it penetrates the fibrous capsule, giving it a softer sensation on palpation. The site, age, sex predilection, and clmieal and radiQgraphic characteristics are sim4ar to the dentigerous cyst, making, nieticulous intraopekative and microsdopic examination imperative. A~aiekOblknSt~rPalL Although ameloblastomas

may occur at any age, most QCCWin the third and fourth decade. There is no significant sex predilection. Eighty percent of ameloblastomas occur in the mandible, and those originating in the maxilla are most frequently found in the pQsterior maxilla, sinus, and floor of the nose. The lesion may appear radisgraphically as a unilocular, mnltilacular, or soap-bubble-type radiolucency with a smooth cortical margin. Ameloblastomas may be asssciated with impacted teeth and commonly cause resorption Qf adjacent roots. Thinning of the cortical bone, with occasional erosion, may cause a sQft rubbery sensation on palpation. Pain is an kmcommon finding unless there is secondary infection, and paresthesia and ulceration of the overlying mucosa are rare. In some ameloblastomas there is a histQry of previous trauma, including tooth extraction. Cavcimma

arising

in dentigerous

cyst.

Al-

though carcinomatons changes of cystic epithelium are uncommon, most are seen after 40 years Qf age. Radiographically, the lesion may appear as a typical dentigerous cyst with defined sclercptic borders, or it may be ill-defined. As the lesisn 8prQgresses, paresthesia, pain? and ulceratisn of the overlying mucQsa may occur. CaldYing

epithelial

odontogenic

tumsr.

The

mean age at the time of diagnssis is 40 years, with no sex predilection. An impacted or unerupted tooth has been reported in 52% sf tie cases. The mandible iS more CQIIIIXIQ~~ inVQhd than the maxilla by a 2:I ratio. Ihe CEOT, which commonly presents as a painless swelling of’ t varied, radiographic appearance. In sQme cases it is totally radiolucent, with an impacted iiooth causing it to closely resemble a dentigerQus cyst. Others may show variable amounts of calci5catiQn, giving it a “driven snow” appearance. At times it may have a honeycomb or multilocular pattern. Cakcijjkg

odsntogenic

cyst (G&in

cyst).

The

calcifying odontogenis cyst may present’as a wellcircums:ribed pericorional sadiolucen~y containing a variable’ amount of calcified materiaI. In early stages of development, it may cldsely res,emble #a dentigerous cyst. I.,ater, distinct radmpaque foci’are seen. @&bough the calcifying odontogenie: cyst may be discQvered at any age, most are found in the second and third decades. The ~alc~fy~~g~~~Q~toge_ nit cyst occurs with equal Ifrequency in the maxilla and mandible. It usually presents as a painless, expansile lesion. Adeno&aGoicf odonbogenic tumoa. The adensmatoid odontogenic tumor ,usually presents as a painless swelling producing expansion Qf the overlying bone. Radiographically it often appears as, a unilocul$r radiolusency surrounding the crown of an unerupted tooth The majority of adenomatoid

1112

odontogenic tumors occur in the anterior maxilla of females under 20 years of age. Ameloblastic fibroma. The ameloblastic fibroma usually presents as a painless, slow growing, unilocular or multilocular radiolucency with welldefined borders. They are commonly found in the molar region of young patients (average age, 15 years). Qdontogenic myxoma. TFhe odontogenic myxoma, which may be associated with an unerupted tooth, usually presents as a painless, slow-growing, expansile lesion with a slight predilection for the mandible. It commonly occurs in the second and third decades and is rarely seen after the age of 50. Although its radiographic appearance may be varied, it usually presents as a multilocular radiolucency. When involving the posterior maxilla, invasion of the maxillary sinus is common. Radicular

cyst associated

with a retained

root.

The radicular cyst is a unilocular radiolucent lesion that arises from a preexisting dental granuloma caused by a necrotic pulp. It occurs as a painless, slow-growing, expansile lesion. The overlying cortical bone may be resorbed, making the lesion soft and fluctuant to palpation. Radicular cysts may involve an entire quadrant and extend into the maxillary sinus. Secondary infection may result in pain and mobility of adjacent teeth. Acute inflammatory exacerbation may cause disruption of the thin sclerotic border that is usually demonstrated radiographically. Although uncommon, some radiolucencies, which appear to be a “garden variety” radicular cyst clinically and radiographically, may prove to be an odontogenic keratocyst on microscopic examination. In extremely rare cases, the radicular cyst may undergo malignant transformation. In summary, a definitive diagnosis cannot be determined based on the history, and clinical and radiographic evaluation. Aspiration with a large-bore needle could prove to be invaluable in determining the diagnosis as well as ruling out the unlikely possibility of a vascular lesion. Although all above lesions must be considered in the differential diagnosis, a dentigerous cyst or an OKC would be most likely. However, the poorly defined appearance radiographically should make one suspicious of a more aggressive, possibly malignant, lesion.

SUBSEQUENT CLINICAL COURSE The area was approached surgically with the decision having been made to marsupialize the lesion should it prove to be cystic. This decision was based on the rela-

tion of the lesion to the maxillary sinus. After administration of a local anesthetic, 4 mL of yellow, viscous exudate was aspirated Corn the lesion. A l.5cm incision was then made along the crest of the alveolus with releasing incisions into the vestibule. The underlying lesion was found to be cystic, lined by a thin, friable, translucent membrane. Additional yellow exudate was removed during repeated saline irrigations. A 1 x l-cm biopsy of the cystic lining was removed. A root tip was identified and removed. A surgical drain, constructed from a l-cm length of intravenous tubing had been previously constructed by flaring both ends. This drain was sutured into the surgical site as the flap was closed, allowing continued access to the cystic space. The procedure concluded without complications. The patient was given postoperative instructions, including use of a syringe to irrigate the cystic cavity daily. The biopsy specimen was submitted to the Surgical Oral Pathology Service. Microscopic examination showed a thin strip offibrous connective tissue surfaced on one side by parakeratinized, stratified squamous epithelium that exhibited a corregated surface and a uniform basal cell layer of cuboidal cells with nuclei polarized away from the basement membrane (Pig 3). These features were characteristic of a parakeratinized OK. The patient was seen I week later, at which time she reported the surgical site to be asymptomatic. The marsupialization tube appeared stable and the surrounding tissue was free from inflammation. The sutures were re: moved and the patient was advised to continue the daily irrigation. The patient was seen again at 1 and 2 months postoperatively, at which time there was no evidence of inflammation at the orifice and the patient continued to be asymptomatic. A panoramic radiograph at 2 months showed a significant decrease in the size of~the lesion, with the formation of a dense corticated rim (Fig (4). The cyst was enucleated 3 months postdecompression. The procedure was performed without complications. The cyst lining was no longer thin and friable. .A thick walled saclike structure easily shelled away from the bony walls. There was no perforation into the maxillary sinus. The defect was closed primarily and complete healing was obtained within the following 2 weeks. Microscopic evaluation of the cyst lining revealed focally hyperplastic parakeratinized and nonkeratinized epithelium with rete ridges (Fig 5). The features were in many areas consistent with normal oral mucosa. In some areas the underlying dense, fibrous connective tissue contained a dense infiltrate of chronic inflammatory cells, including lymphocytes and plasma cells. The patient was followed up over the next 5 years. Periodic panoramic radiographs showed a continued decrease in the radiolucency size and remodeling of the bony defect. Evaluation at her $-year postoperative recall examination revealed no clinical evidence of disease. However, a radiograph showed a 1.5 X 1.54~1, well-circumscribed radiolucency with a cortical border distal to the first molar (Fig 6) highly suggestive of a recurrent lesion. The lesion was explored and found to be cystic. The thin, soft-tissue walls of the cyst were curetked. Microscopic evaluation showed a recurrent 0% with features essentially identical to the original biopsy specimen. The defect healed without complication, and the patient has now been followed for an additional year without evidence of recurrence.

VINCENT,

1113

DEAHL, AND JQIINSON

FIGURE 3. The initial incisional biopsy revealed fibrovascular connective tissue surfaced by a thin, uniformthickness, parakeratinized, stratified squamous epitbelium without rete ridges, but with a uniform cuboidal basal cell layer and a corregated surface diagnostic of a parakeratinized odontogenic keratocyst (hematoxylin-eosin stain, original magnification X63).

The keratocyst is one of two cysts (the other is the calcifying odontogenic cyst) derived from odontogenic epithelium that can be diagnosed based on its microscopic features alone. For a specific diagnosis of nonkeratinizing odontogenic cysts, a radiograph showing the relationship of the cyst to teeth and sometimes the condition of associated teeth is usually necessary.

The OKC epithelium apparently originates from remnants of the dental Bamina. Bdontogenic keratocysts are identified most often in the second and third decades of life, about twice as often in the mandible as the maxilla. The third molar region is the most common location, followed by the canme region.’ Histologically, OKCs exhibit ~arakera~~~~zat~~n in over 85% of cases reported, with the remeining cases most often exhibiting orthokeratmization.2 Occasional cysts may exhibit both or&o- and

FIGURE 4. A panoramic radiograph made 2 months postmarsupialization dense cortical periphery.

showing a decrease in size of the lesion and formation of a

FHGURE 5. EQucledion of the marsupialized cyst showed a hyperplastic, parakeratinized and nonkeratinized stratified squamous epithelid lining siniilar to oral mucosa (hematoxylin-eosin stain, otiginal ma&fication‘ X63).

parakeratinized areas. The microscopic features are important because of the variable prognosis for the different histologic types. Parakeratinized variants have a much higher recurrence rate than the other odontogenic cysts and many odontogenic tumors. Studies estimate the rate of recurrence to be as low as 5% or as high as 62%. These studies are undoubtedly affected by surgical access to the cysts, the surgical technique used for removal, and the

length of foolPow-up. Orthokeratinized variants have a recurrence rate estimated at less than IQ%. The recurrence rate is higher for patients with multiple OK& as is often noted in basal cell nevus syndrome .3-6 The reason for the high recurrence rate remains unknown; however, the difficulty of removing odontogenic keratocysts due to their thin friable nature has been suggested as a possible cause.

FIGIJRE 6. Periapical radiograph showing a welldemarcated, corticated l;ddliolucency suggest& of a recurfent cyst. Enucleation showdd a parakeratinized OKC.

VINCENT,

DEAHL, AND JOHNSON

While this may be the reason for the persistence rather than the recurrence of some lesions, the redevelopment Qf keratocysts after several years of documented lesion-free follow-up would seem to suggest that an additional mechanism of recurrence must be present. With the current case, the marsupialized cyst lining was easily removed, virtually intact, and the epithelial lining no longer resembled that of a parakeratinized OKC. Yet, after a 6-year period, the cyst recurred at the surgical site and it again had the microscopic features of a parakeratinized OKC. White this does not completely exclude the possibility of recurrence/persistence from an incdampletely removed cystic lining, it seems unlikely. A few cases Qf OKCs treated with marsupialization or decsmpression priQr to enucleation have been repsrted in the past. Some reports describe the cysts as primordial or simply as keratocysts without mention of the type of keratinization.7 Eyre and Zakrzewska’ described four cases of OKC treated with marsupialization. Examination of the cystic epithelium after decompression revealed a progressive change to resemble the normal stratified squamous epithelium of oral mucosa. Two of the four cases recurred, at 2 and 4 years after the original excision. Tucker and associates’ reported mars~~ia~~zat~o~of a mtindibular keratocyst ,fol1Qwedby enucleation 13 months later. The reported histolsgic #features of the second surgical specimen were similar to the first. There was no recurrence at 30 months after the original ‘surgery. Zachariqde’s and colk~gues~~ reported 16 cases of OKC, 01%of which was treated with marsupializatioti. Four recurr&ces yere noted, but no mention was made concerning: ‘the ‘marsupialized case. ForsseU1’ reported a setiFs of primordial cysts with 122 cases having fofollo~v-up.Eleven cases were treated with m~supializa@n and 3 of these recurred. Browne” evah$ed 65 patients treated for OKCs witb varying metvo+, including enucleation with primary &sure, e$lkacfeat,tion with open packing, a& ~arsu~~~~~za~~~.None .of the treatment methods seeq~ed to sig&ica&y $qange the recurrence r&ie. Rud aMFin&orgP3 follqwed 21 cases of odontogenic ke~~ocys~‘jpostQperat~\ralyfor up tQ 16

years. Two cases were treated with marsupialization. These cases had no recurrence evident when checked radiographically 16 years ilater. Pindborg and Hansen’” had previously reviewed 14 cases of OKC and foseandno difference in the frequency of recurrence in cases treated with ermcleation with or without prior marsupializatiQn. Hopper” and Hickoryl6 reported marsupialization sf three eBKCs in two patients with multiple lesions. One patient was followed for 9 years without recurrence. References 1. Regezi JA, Sciubba JJ: Cysts of the oral regions,

2.

3.

4. 5.

6.

7. 8.

9.

10.

11. 12. 13. 14. 15. 16

in Regezi JA, Sciubba JJ (eds): Oral Pathology, Clinical-Pathologic Correlations. Philadelphia, PA, Saunders, 1989 ,(chap 10) Brannon RB: The odontogenic keratocyst-A clinicopathologic study of 312 cases. Part II. Histologic features. Oral Surg Oral Med Oral Path01 43:233. 1977 Brannon RB: The odontogenic ken&cyst-A clinicopathoiogic study of 312 cases. Part I. Clinical featwes. Oral Surg Oral Med Oral Path01 42~54, 1976 Wright JM: The odontogenic keratocyst: Orthokeratinized variant. Oral Surg Oral Med Oral Pathol 51:$9, 1981 Partridge M, Towers IF: The primordial cyst (odontogenic keratocyst): Its tumor-like Eharacteristi& and behavior. Br J Oral Maxillofac Sum 25:271. 11987 Stoelinga PJW, Cohen MM,“Morgan’ AI? The origin of keratocysts in basal cell nevus syndrome. Bnt J Oral Surg 33:659, 1973 Main DMG: Epithelial jaw cysts: 18 years of the WHO classification. J Oral Pathol 14:1, 1985 Eyre J, Zakrzewska JM: The conservative management of large odontogenic keratocysts. Br 3 Oral Maxiliofac Surg 23:195, 1985 Tucker WM, Pleasants JE, MacComb WS: Decompi-ession and secondary enucleation of a mandibular cyst: &eport of a case. J Oral Surg 30:229, 1972 Zachariades N, Papanicolaou S, Triantafyllou D: Odonto.genic ,keratocysts: Review of the litera&re and report of sixteeti cases. J Oral Maxillofac Surg 42:17?. 1985 Forssell K: The primordial cyst. Proc F&n Dent Sot 76: 129, 1980 Byowne RM: The odontogenic keratocyst. Clinical aspects. Br Dent J B28:225, 1970 Rud 9, Pindborg JJ: Odontogenic keratocysts: A foHow-up study of 21 cases. J Oral Surg 27:323, 1969 Pindborg JJ, Hansen 9: Studies on odontogenic cyst epithelium. Acta Pathol Microbial Stand 58:2&j, 1963 Mopper FE: Bilateral cysts of the mandible. Br Dent J 153:386, 1982 Hickory JE, Gilliland RF, Wade WM, et al: conservative treatment of cysts of the jaws in nevoid basal cell carcinoma syndrome: Report of a case. J Oral Surg 33:693, 1975