Oral amelanotic malignant melanoma: a rare entity with diagnostic challenge

Abstract

Primary malignant melanomas of the mucosal areas of the head and neck are very rare tumors and they account for less than 1% of all melanomas. A 61-year-old male was referred to our clinic for the management of a palatal lesion that had been diagnosed from the referral center, as a malignant myoepithelial tumor. Intraoral  examination revealed a large variegated, lobulated palatal swelling, which covered the hard and soft palate. A re-biopsy at our center revealed sheets, bundles, and occasional fascicles of atypical elongated epithelioid and spindle shaped cells, exhibiting vesicular and enlarged nuclei with prominent nucleoli. The nucleoli appeared to be ‘cherry red’ in color. Melanin pigment was however not identified in any of the cells, hence the suspicion of an amelanotic melanoma. Immunohistochemical staining was strongly positive for HMB45, S100 and vimentin. Hence we report a case of intra-oral amelanotic  elanoma, which based on the English literature and to the best of our knowledge, is the first case report from West Africa. 

Key words: oral, amelanotic, malignant melanoma, Running header