Desmoplastic ameloblastoma: A case report

Desmoplastic ameloblastoma: A case report

CASE REPORTS J Oral Maxillofac Surg 60:1186-1188, 2002 Desmoplastic Ameloblastoma: A Case Report Suvy Manuel, BDS,* Deepti Simon, BDS,† R. Rajendran,...

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CASE REPORTS J Oral Maxillofac Surg 60:1186-1188, 2002

Desmoplastic Ameloblastoma: A Case Report Suvy Manuel, BDS,* Deepti Simon, BDS,† R. Rajendran, BSc, MDS, PhD, FIMSA,‡ and B. Raghava Naik, BDS, MDS§ Ameloblastoma is a benign neoplasm derived from enamel organ.1 Several histologic subtypes of this tumor have been described. The desmoplastic variant was first described in detail by Eversole et al2 in 1984. Waldron and El Mofty3 in 1987 described a “hybrid” lesion of desmoplastic ameloblastoma (DA) and conventional ameloblastoma, which they suggested represented a “collision tumor.” Although DA has been accepted as a distinct clinicopathologic entity, some researchers still regard it as a histologic variant of ameloblastoma.4,5 Because the clinical and histopathologic data concerning this tumor are limited, we report a new case of DA, in the interest of expanding on what is known about this uncommon lesion.

Report of a Case A 20-year-old woman presented for diagnosis and management of a painless progressive swelling in the left maxillary vestibule, in the region of canine and first premolar teeth (Fig 1). The swelling was noticed 3 weeks before the presentation and was palpable extraorally at the left ala of the nose. The medical history was noncontributory. Intraoral examination revealed a firm, well-defined 2.5- ⫻ 2-cm mass that was covered with normal mucosa and extended into the vestibule. There was no palatal expansion. The adjacent teeth were vital and nonmobile. Intraoral periapical radiographs revealed a noncorticated, inverted

pear-shaped lytic defect measuring 1 ⫻ 1.75 cm. There was some suggestion of mixed radiopacity and radiolucency. The lesion extended from the alveolar crest to the region between the apices of the roots of the canine and first premolar teeth. The roots of these teeth were diverged but root resorption was not evident. The periodontal ligament spaces appeared to be intact (Fig 2). Needle aspiration failed to yield fluid. With a provisional differential diagnostic impression of a benign neoplasm or a fibro-osseous lesion, under local anesthesia a buccal flap was raised and the overlying thin cortical plate was removed. A firm, well-circumscribed, granular, nonencapsulated intraosseous mass was shelled out with relative ease. The surface of the osseous bed of the tumor had indentations, which suggested possible infiltration. Peripheral ostectomy was performed, and the wound was closed primarily. Gross examination revealed a 2- ⫻ 2.5-cm round mass of firm grayish white tissue. The cut surface was grayish brown, with evidence of peripheral condensation and stromal predominance. No regions of hemorrhage, pigmentation, or calcification were noted. Microscopic examination revealed small islands and slender cords of odontogenic epithelium in a densely collagenized stroma. The peripheral low cuboidal ameloblast-like cells of the nests were inconspicuous; the more central epithelial cells were loosely arranged and spindle shaped (Figs 3, 4). The stroma was abundant, densely collagenized without much inflammation. The diagnosis was DA. The postoperative period was uneventful. The patient is disease free 22 months after surgery and is under routine follow-up.

Discussion Received from the Government Dental College, Trivandrum, Kerala State, India. *Senior Resident, Department of Oral and Maxillofacial Surgery. †Senior Resident, Department of Oral and Maxillofacial Surgery. ‡Professor and Head, Department of Oral Pathology and Microbiology. §Professor and Head, Department of Oral and Maxillofacial Surgery. Address correspondence and reprint requests to Dr Manuel: Mangalam House, Temple Lane, Sreekariyam PO, Trivandrum 695 017, Kerala State, India; e-mail: [email protected] © 2002 American Association of Oral and Maxillofacial Surgeons

0278-2391/02/6010-0016$35.00/0 doi:10.1053/joms.2002.35030

Approximately 50 cases of DA have been reported to date in the English literature.6 The tumor occurs most commonly in the third to fifth decades of life, with an equal male/female ratio. DA accounts for 4% to 5% of all ameloblastomas.6 Available data indicate that DAs occur less often in Asian patients than in Western patients. Our patient represents only the third case of DA to be reported in a subcontinental Indian.7 This could be the result of underreporting of cases from this region of the world. More than 70% of the DA cases reported arose within the anterior/premolar regions of the jaws, and roughly half of the tumors occurred in the maxilla.8 This is in sharp contrast with conventional ameloblas-

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FIGURE 1. Desmoplastic ameloblastoma at initial presentation, showing a nodular 2.5- ⫻ 2-cm mass in the left maxillary vestibule anterior to the buccal frenum (arrowhead).

tomas, which are usually found in the mandibular molar/ramus regions. DA also is characterized by features that differ from those of conventional ameloblastomas, particularly regarding both their radiographic and microscopic appearances. The grossly solid nature of the tumor may be attributable to its pronounced stromal desmoplastic component. The classic radiographic feature of DA is that of a mixed

FIGURE 2. Periapical radiograph reveals an inverted pear-shaped radiolucency with splaying of the roots of the maxillary canine and first premolar teeth. Note the ill-defined margins.

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FIGURE 3. Photomicrograph of the tumor showing islands of neoplastic odontogenic epithelium with peripheral palisading of condensed cuboidal or low columnar cells, nuclear hyperchromatism, and tendency to separate from their surrounding cells of the central stellate reticulum. Note the pronounced stromal desmoplasia. (hematoxylin and eosin stain, original magnification ⫻10).

radiopaque/radiolucent lesion, often leading to a clinical diagnostic impression of a fibro-osseous lession.9 The radiographic appearance of our patient’s tumor consisted of a rarefaction with ill-defined noncorticated margins, similar to what was reported for DAs by Kawai et al.10 Most reported DAs show no resorption of the associated tooth roots, as was also true in our case. The duration of symptoms has ranged from 2 weeks to 18 months.11 Most of the previously reported tumors were detected before they reached 2 cm in diameter.12 Lam et al13 reported that the epithelial elements in DAs could exhibit squamous metaplasia or are compressed into thin strands. These changes mimic those of squamous odontogenic tumor and thus create the potential for diagnostic confusion. Patrick et al6 reported that splaying of roots is indicative of a recent rapid increase in tumor size, which could be a reflection of its inherent biologic nature.

FIGURE 4. High-power view (hematoxylin and eosin stain, original magnification ⫻40).

1188 According to Philippsen et al,14 radiographically ill-defined borders suggest an infiltrative process with propensity to recur. Thus the pronounced stromal reaction characteristic of DAs can be viewed as a defensive response of the host to the “aggressive” tumor. The present case shows local infiltration and nonencapsulation. This, along with the fact that recurrences of DAs have been documented by more than one author, suggests potentially aggressive biologic behavior.4,7,11 The ill-defined borders of DAs reflect the desirability for a relatively radical approach to treatment. In view of the paucity of DA case series and the only limited understanding of its biologic behavior and prognosis, the proper treatment strategies for DA are not entirely defined at this time.

References 1. Shafer WG, Hine MK, Levy BM: A Textbook of Oral Pathology (ed 4) Philadelphia, PA, Saunders, 1993, p 276 2. Eversole LR, Leider AS, Hansen LS: Ameloblastomas with pronounced desmoplasia. J Oral Maxillofac Surg 42:735, 1984 3. Waldron CA, El Mofty SK: A histopathologic study of 116 ameloblastomas with special reference to the desmoplastic variant. Oral Surg Oral Med Oral Pathol 63:441, 1987 4. Keszler A, Paparella ML, Dominguez FV: Desmoplastic and non-desmoplastic ameloblastoma: A comparative clinicopathological analysis. Oral Dis 2:228, 1986

5. Raubenheimer EJ, Van Heerden WF, Noffke CE: Infrequent clinicopathologic findings in 108 ameloblastomas. J Oral Pathol Med 24:227, 1995 6. Patrick JL, Richard CF, Meredith A: Mixed radiolucent/radiopaque lesion of the maxilla. J Oral Maxillofac Surg 58:86, 2000 7. Ng KH, Siar CH: Desmoplastic variant of ameloblastoma in Malaysians. Br J Oral Maxillofac Surg 31:299, 1993 8. Takata T, Miyauchi M, Ogawa I, et al: So-called ‘hybrid’ lesion of desmoplastic and conventional ameloblastoma: Report of a case and review of the literature. Pathol Int 49:1014, 1999 9. Kaffe I, Buchner A, Taicher S: Radiologic features of desmoplastic variant of ameloblastoma: Oral Surg Oral Med Oral Pathol 76:525, 1993 10. Kawai T, Kishino M, Hiranuma H, et al: A unique case of desmoplastic ameloblastoma of the mandible: Report of a case and brief review of the English language literature. Oral Surg Oral Med Oral Pathol 87:258, 1999 11. Takata T, Miyauchi M, Ito H, et al: Clinical and histopathological analysis of desmoplastic ameloblastoma. Pathol Res Pract 195:669, 1999 12. Cawson RA, Langdon JD, Eveson JW: Surgical Pathology of the Mouth and Jaws. Oxford, England, Wright, Butterworth– Heineman, 1996, p 62 13. Lam KY, Chan AC, Wu PC, et al: Desmoplastic variant of ameloblastoma in Chinese patients. Br J Oral Maxillofac Surg 36:129, 1998. 14. Philippsen HP, Ormiston IW, Reichart PA: The desmo- and osteoplastic ameloblastoma. Histologic variant or clinicopathologic entity? Case reports. Int J Oral Maxillofac Surg 21:352, 1992