WEAVER

J

Oral Maxlllofac

49 1243.1246.

1243

ET AL

Surg

1991

Central Neurofibroma

of the Mandible:

Report of a Case BRYAN D. WEAVER, DDS,* ROBERT W. GRAVES, DDS,t GORDON G. KEYES, DDS, MS,* AND DAVID A. LATTANZI, DOSS

Soft-tissue neurofibromas are relatively common lesions, but intraosseous nerve sheath neoplasms are relatively rare, with as few as 29 cases reported.’ The most common site of occurrence of soft-tissue neurofibroma is the tongue.’ Central neurofibroma has been reported in both the maxilla and mandible, but more commonly in the latter. Neurofibroma rarely occurs as a solitary lesion’ except when present in the jaw bones. In contrast, multiple lesions are usually seen in von Reckling* Assistant Professor, Department of Oral and Maxillofacial Surgery. West Virginia University School of Dentistry. Morgantown. WV. t Professor and Chairman, Department of Oral and Maxillofacial Surgery, West Virginia University School of Dentistry. Morgantown. WV. f Professor, Department of Oral Pathology. West Virginia University School of Dentistry. Morgantown, WV. 5 In private practice of oral and maxillofacial surgery. Clarksburg. WV. Address correspondence and reprint requests to Dr Graves: Department of Oral and Maxillofacial Surgery. West Virginia University School of Dentistry. Health Sciences Center North. Room 1033, Morgantown. WV 26.506. cd! 1991 American geons

Association

of Oral and Maxillofacial

Sur-

0278-2391/9114911-0023$3.00/O

FIGURE

I,

Preoperative

panoramic

radiograph

showing

hausen’s neurofibromatosis.’ In this report. we present an additional case of solitary neurofibroma of the mandible. and show the role of immunohistochemistry in the diagnostic process. Report of a Case A 22-year-old black, mentally impaired, woman was seen in the Department of Oral and Maxillofacial Surgery for examination of a left facial swelling in April of 1986. The swelling had been present for approximately 2 years. The patient had no complaint of pain or paresthesia. Examination revealed an obvious left facial swelling. Intraorally there was left buccal cortical expansion of the mandible without evidence of perforation. There were no palpable thrills over the swelling, and the lesion was hard and nonmovable. Regional lymph nodes were nonpalpable. A panoramic radiograph showed a large (5 x 3 cm), primarily radiolucent, well-circumscribed lesion of the left body of the mandible. The lesion had a few flecks of opacity visible in the anterior portion and extended to the inferior cortex of the mandible. The roots of adjacent teeth were displaced (Fig I). The patient was admitted to the hospital, and under general anesthesia multiple extractions of the associated teeth and an incisional biopsy of the left mandibular mass were performed. A frozen section was diagnosed as a spindle-cell tumor. A decision was made to wait for examination of permanent sections before removal of the lesion. These sections showed a nonencapsulated, mod-

a destructive

lesion of the mandible

and tooth

displacement.

CENTRAL NEUROFIBROMA

1244

OF THE MANDIBLE

erately cellular, neoplasm composed of numerous spindle shaped cells. Neither a storiform pattern nor Antoni type A or Antoni type B tissue were observed (Fig 2).

FIGURE 2. Photomicrograph of specimen shows spindleshaped cells and flowing bundles of cellular connective tissue (hematoxylin-eosin stain, original magnification x40).

The differential diagnosis included benign peripheral nerve sheath tumor and fibrous hystiocytoma. Immunoperoxidase staining for S-100 and lysozyme were performed to distinguish between these two diagnostic possibilities. Electron microscopy also was performed. The results of immunohistochemistry revealed a spindle cell neoplasm strongly S-100 positive (Fig 3). with no staining of tumor cells with lysozyme. This suggested that the cell type involved was of peripheral nerve origin and not an enzyme-containing cell such as the histiocyteimacrophage. The electron micrographs confirmed these findings. Cells with distinct, continuous, basal lamina demonstrating cytoplasmic extensions and enfolding of the plasmalemma were mixed with cells showing discontinuous and indistinct basal lamina. A diagnosis of neurofibroma was made. The patient was returned to the operating room 3 days later. Enucleation and curettage of the lesion was performed through an intraoral approach. The inferior alveolar nerve was sacrificed at surgery due to involvement in the tumor. The periosteum remained intact on the buccal and lingual surfaces following removal of the tumor. An osteosynthesis A0 plate was placed from the left mandibular ramus to the symphysis through an intraoral approach to add strength to the weakened mandible. although no fracture resulted from enucleation of the lesion (Fig 4). The flaps were then repositioned and sutured over the A0 plate. Follow-up in January of 1987 showed no evidence of recurrence and sufficient bony depositioned in the tumor site to allow removal of the bone plate. which had become exposed intraorally (Fig 5). Evaluation for sensory deficit was impossible due to the patient’s mental status.

Discussion FIGURE 3. Photomicrograph of specimen shows central area of cells stained darkly for S-100 protein (immunoperoxidase stain, original magnification X 100).

FIGURE 4.

Postoperative

In neurofibroma of the head and neck, the branches of the trigeminal and occasionally the fa-

panoramic radiograph shows A0 plate in place.

WEAVER ET AL

FIGURE 5,

1245

Panoramic radiograph taken 9 months after the operation shows healing of the defect after removal of the A0 plate.

cial nerve serve as the tissue of origin.” Mandibular lesions are usually derived from the inferior alveolar nerve and develop in the mandibular canal. The neurofibroma creates an ovoid osteolytic enlargement of the mandibular canal, usually well demarcated, and in complete continuity with the canal at both ends.’ When this occurs, it is not uncommon for the patient to experience varying degrees of discomfort. pain, or paresthesia. A review by Ellis and Abram? has shown a 2: 1 predilection for females, with an average age of 29 years. It is important for the clinician to distinguish between neurofibroma and schwannoma. since the potential clinical behavior of the two can be different. The neurofibroma is an nonencapsulated neoplasm containing small nerve fascicles in an unorganized collagenous matrix. In the peripheral type, the lack of encapsulation allows the tumor to infiltrate contiguous tissues making complete surgical removal difficult.’ In central neurofibroma, lack of encapsulation generally poses little difficulty in complete identification of the lesion. Of clinical significance is the fact that malignant transformation may occur in 8% to 13% of patients with neurofibromatosis, especially when multiple neurofibromas are present.’ There appears to be a greater danger if the lesion is associated with neurofibromatosis rather than as a solitary lesion. Clinically. benign nerve sheath tumors are slow growing and are often present for some time prior to the patient seeking treatment. Swelling and enlargement of the bone in the area of the central neurofibroma is the most common clinical symptom; however, pain occasionally may be present. Although malignant changes do occur in neurofibromas. thorough curettage is the preferable initial treatment for intraosseous lesions.* However, recurrence has been reported. Gnepp and Keyes’ indicated that of the 15

intramandibular neurofibromas cited in the literature four recurrences were reportecl. a rate of 23.5%. Studies have shown that operation on a neurofibroma does not lead to malignant change and incomplete removal is not harmful and may lead to regression. ’ Occasionally, the two nerve stumps can be repositioned and sutured, improving nerve function postoperatively. Lesions composed of ovoid to spindle-shaped cells in a fibrous stroma have traditionally presented difficulty in diagnosis. The case reported here is no exception. Histologically, the differential diagnosis was fibrous histiocytoma versus neurofibroma. Immunoperoxidase staining provided a means to differentiate these two possibilities. In well-differentiated lesions, histiocytes have been found to stain positively for lysozyme and other enzymes. u’.” S-100 protein has been found in a variety of tissues, especially those of the central and peripheral nervous system.” A stain for lysozyme in this lesion was negative. Occasional, nonspecific inflammatory cells stained positively, as expected, but the tumor cells uniformly failed to react. With S-100 protein stain, however, the tumor cells uniformly showed fine, brown, granules suggesting peripheral nerve sheath origin. Together, immunochemical techniques for lysozyme and S-100 protein were of considerable value in distinguishing between the two main diagnostic possibilities in this case. The diagnosis of neurofibroma was further confirmed by the electron-microscopic findings. References I. Polak M. Polak G. Brocheriou C. et al: Solitary neurofibroma of the mandible: Case report and review of the literature. J Oral Maxillofac Surg 47:65. 1989 3. Toth BB. Long WH. Pleasants JE: Central pacinian neurofibroma of the maxilla. Oral Surg 39530. 1975

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3. Lucas RB: Pathology of Tumors of the Oral Tissues (ed 2). London, Churchill Livingstone, 1972, p 199 4. Eversole LR: Central benign & malignant neural neoplasma of the jaws: A review. J Oral Surg 27:716. 1969 5. Papadopoulos H, Zachariades N, Angelupoulos AP: Neurofibroma of the mandible: Review of the literature and renort of a case. Int J Oral Sum 10:293. 1981 6. Ellis’GL. Melrose RJ, Abrams AM: Intraosseous benign neural sheath neoplasms of the jaws: Report of seven new cases and review of the literature. Oral Surg 44:731, 1977 7. Gnepp D, Keyes G: Central neurofibromas of the mandible: Report of two cases. J Oral Surg 39:125, 1981 8. Brady G, Schaffner D, Joy E, et al: Solitary neurotibroma of the mandible. J Oral Maxillofac Surg 40:453. 1982

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9. Griffith BH, Lewis VL, McKinney P: Neurofibromas of the head and neck. Surgery, Gynecol Obstet 160534. 1985 10. Kerdel FA, Morgan EW. Holden CA. et al: Demonstration of alpha-one antitrypsin and alpha-one antichymotrysin in cutaneous histiocytic infiltrates and a comparison with intracellular lysozyme. J Am Acad Dermatol 7: 177, 1982

I I. Burgdorf WHC, Duray P, Rosai J: Immunohistochemical identification of lysozye in cutaneous lesions of alleged histiocytic nature. Am J Clin Pathol 75: 162. 1981 12. Bennington JL: Immunomicroscopy: A Diagnostic Tool for the Surgical Pathologist. Philadelphia, PA, Saunders, 1986, p 337

Central neurofibroma of the mandible: report of a case.

WEAVER J Oral Maxlllofac 49 1243.1246. 1243 ET AL Surg 1991 Central Neurofibroma of the Mandible: Report of a Case BRYAN D. WEAVER, DDS,* RO...
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