Primary Malignant Melanoma of the Gingiva: A Case Report and Review of Literature

Abstract

Mucosal melanoma of the head and neck is a relatively rare condition that has been poorly understood, characterized and studied. A 28-year-old male patient reported a swelling in relation to the right upper incisor teeth. The lesion was mobile, with slight bleeding on probing. Differential diagnosis of gingival hyperplasia/fibrosis, giant cell epulis, Kaposi s sarcoma, and malignant melanoma were kept. Histopathological sections showed sheets of pleomorphic spindle cells with intracytoplasmic brown-black pigment, involving the lower part of the squamous epithelium- Tumor cells were positive for S-100 and HMB-45 (Human Melanoma Black) immunostain and a diagnosis of malignant melanoma was rendered. The patient underwent partial maxillectomy and the case was categorized as stage If. He also received regional radiotherapy: however after five months, the patient presented with a metastasis to the lymph nodes that was confirmed on fine needle aspiration cytology (FNAC). The patient underwent radical neck dissection that showed a large tumor mass. In contrast to cutaneous melanoma, the mucosal melanomas have an aggressive vertical growth phase. Different cell types, like spindled, plasmacytoid, and epithelioid may be observed. The treatment of choice is complete excision with adequate negative margins. The role of radiotherapy is not clearly defined since malignant melanoma is relatively insensitive to radiation. The prognosis for mucosal melanoma is generally quite poor because of its tendency to invade and cause early hematogenous metastasis. Nodal involvement reduces survival time and multiple local recurrences are the most common cause of treatment failure.

Keywords

• Malignant melanoma
• Gingiva
• HMB-45
• Mucosal melanoma
• Head and neck