ANAPLASTIC TUMOR OF THE ANTERIOR MAXILLA: DIFFERENTIAL DIAGNOSIS AND IMMUNOHISTOCHEMICAL STUDY

The present study reports a rare case of anaplastic malignant melanoma in a 23-year-old female patient, in the anterior maxilla. On clinical examination, the lesion presented as a 5-cm sessile nodule, with brownish irregular macules on the mucosal surface, painless, with a firm consistency ranging from teeth 14 to 24 with palatal and nasal extension causing facial asymmetry and dental mobility. The computed tomography showed irregular lytic bone reabsorption, without dental involvement. The incisional biopsy followed by microscopic examination suggested primitive neuroectodermal tumor, due to the presence of round blue cells, periodic acid-Schiff (PAS)-positive clear cells, with considerable pleomorphism, atypical mitosis, hemorrhagic areas, and coagulative necrosis. Immunohistochemistry revealed high-grade epithelioid neoplasm and a diagnosis of invasive melanoma was concluded; the melanoma was positive for S-100 protein, gp100, and SOX 10 antigens. The patient underwent partial maxillectomy with no postsurgical complications after 3-month follow-up. The aggressive nature of the lesion and its prognosis are discussed.