Abstract

Spindle-cell melanoma is a rare and aggressive variant of malignant melanoma. Lesions are frequently amelanotic. Histopathological findings show atypical and spindled cells that can mimic carcinomas, sarcomas, and lymphomas. Subungual melanomas are rarer still and typically display hyperpigmentation clinically. We present a rare case of spindle-cell melanoma of the nail mimicking squamous cell carcinoma. A 49-year-old male presented with a lesion localized to the right nail present for over one year. Biopsy of the lunula and fingernail revealed atypical spindled cells highlighted by S100 and SOX10 stains. Pancytokeratin, melan-A, PRAME, desmin, CD34, and CD31 stains failed to highlight the neoplastic cells. The histopathologic changes were consistent with spindle-cell melanoma, measuring at least 2.6 mm in thickness, pathologic stage T3a. Spindle-cell melanomas can mimic squamous cell carcinomas and other malignant lesions. Special staining and immunohistochemistry are required to establish the diagnosis. This case serves as a reminder to consider spindle-cell melanoma in the differential diagnosis of nail lesions despite its rarity and atypical localization.