Amelanotic melanoma of the tongue
A 19-year-old man presented with a raised non-tender lesion on the tongue. The lesion was present since three years and was gradually increasing in size. The patient had a history of taking paan paraag and gutka for the past seven to eight years. Clinical examination showed an ulcerated lesion of 6 × 6 cm, present along the left lateral border of the tongue extending from the base to the tip []. The patient also had a palpable cervical lymph node of size 3 × 2 cm on the left side.\nThe tongue lesion was excised and we received a linear gray white mass of size 5 × 5 cm with an ulceration of 1 × 1 cm on the surface. Cut section showed a gray white growth of 4 × 4 cm involving the base but not the lateral margins.\nOn microscopy, tumor cells were seen involving the dermoepidermal junction and composed of sheets and nests of cells separated by scant fibrous stroma []. Tumor cells revealed nuclear pleomorphism, prominent nucleoli, and tumor giant cell formations. High mitotic activity was conspicuous with abnormal mitotic figures. In focal areas, the cells were spindle shaped and also epitheloid []. Tumor was seen infiltrating into the superficial squamous epithelium in a pagetoid fashion. Underlying skeletal muscle was also infiltrated.\nFine needle aspiration cytology (FNAC) of the left cervical lymph node showed good cell yield with a lymphocytic background. Sheets and clusters of tumor cells with moderate amount of cytoplasm, pleomorphic nuclei, and prominent nucleoli were identified. High mitotic activity and tumor giant cells were seen. Differential diagnosis included rhabdomyosarcoma, poorly differentiated squamous cell carcinoma, amelanotic melanoma, and hemangiopericytoma. Immunohistochemistry was done with a panel of markers. Desmin was negative, whereas vimentin was focally positive. Epithelial Membrane Antigen (EMA) and CD34 were negative. However, the tumor cells showed strong diffuse positivity for Human Melanoma Black 45 (HMB) [] confirming the diagnosis of malignant (amelanotic) melanoma of the tongue with metastases to the left cervical lymph node.