Primary chondro-osseous melanoma (chondrosarcomatous and osteosarcomatous melanoma).

Melanoma can rarely show malignant chondro-osseous differentiation and can cause diagnostic confusion. We report 3 cases of primary melanoma with extensive bone and cartilage matrix. The first case arose in the nasal mucosa of a 72-year-old woman, the second case in the left index finger of a 26-year-old woman and the third case in the left cheek of a 68-year-old woman. In tumors where osseous and chondroid differentiation appear in mucosa and skin, primary melanoma with chondro-osteosarcomatous differentiation should be considered in the differential. Careful histological examination together with clinical correlation and ancillary immunohistochemical studies can ensure the correct diagnosis is made.