Fine needle aspiration biopsy of myxoid metastasis of malignant melanoma.

The cytopathologic features of the fine needle aspiration biopsy of a myxoid metastasis of a cutaneous malignant melanoma are documented. The cytologic findings included fusiform-to-round cells with elongated cytoplasmic processes, fibroblastlike cells and inflammatory cells in a characteristic amorphous background substance. Immunocytochemical staining for S-100 protein was positive. The cytologic findings correlated well the histologic, histochemical, immunohistochemical and ultrastructural studies of the neoplasm. The cytologic differential diagnosis between metastases of malignant melanoma and other myxoid tumors of soft tissues is discussed.