A case of amelanotic malignant melanoma of the maxillary gingiva

A rare case of amelanotic malignant melanoma of the maxillary gingiva is reported. A 52-year-old man was referred to our hospital because of swelling of the maxillary gingiva. A clinical examination revealed a 14×10 mm amelanotic nodule of the 5 6 region with swelling of the cervical lymph nodes. The histologic diagnosis of a biopsy specimen was spindle cell carcinoma or suspicion of sarcoma. The patient underwent partial maxillectomy and radical neck dissection. Histologic examination of the resected specimen revealed spindle and polygonal tumor cells with no apparent melanin. There was metastasis to three cervical nodes. These tumor cells showed a positive reaction with anti-S100 protein and anti-HMB45 monoclonal antibodies, and a final diagnosis of amelanotic malignant melanoma was made. The patient is free of tumor as of 13 months after the operation.