Melanoma of the Oral Cavity: an Analysis of 46 New Cases with Emphasis on Clinical and Histopathologic Characteristics.

Melanoma of the oral cavity is a rare malignancy that carries a poor prognosis. We identified 46 new cases of both primary and metastatic melanoma to the oral cavity. Following IRB approval, these cases were obtained from the Oral Pathology Biopsy Service archives of the UF College of Dentistry (1994-2014), the UK College of Dentistry (1997-2015), and the UM Medical Center (1988-2015). All slides were reviewed. The location, age, race, gender, clinical impression, duration of lesion, histopathologic diagnosis, and histopathologic features were recorded. Cases from the facial skin and those with an ambiguous diagnosis were excluded. Forty-six cases fulfilled the inclusion criteria with 32 primary cases, 11 known metastases, and 3 cases where metastasis could not be excluded. The primary cases included a total of 20 females and 12 males with an average age of 66.7 (range 27-95), and the majority (80 %) of the patients were Caucasian when race was known. Twenty-two of the 32 primary cases (68.8 %) were located in the maxillary mucosa, 5 in the mandibular mucosa or bone, and 5 in other locations. The clinicians' impressions varied from benign fibrous growths to high grade malignancies. The histopathology varied widely among the cases, however two cell types predominated (often in combination): epithelioid cells (50.0 %) and spindle cells (50.0 %). Only 53.1 % demonstrated melanin pigmentation. Oral melanoma remains one of the most diverse clinical and histopathologic diagnoses. Better understanding of this neoplasm may promote earlier diagnosis and may lead to improved outcomes.