Cutaneous metastases of a giant cell tumor of bone: case report

A 47-year-old patient with the previous history of a giant cell tumor of the left femur presented with 3 cutaneous nodules located on the face. Histologic examination revealed skin metastases of a giant cell tumor of bone, with dermal and subcutaneous nodules characterized by multinucleate giant cells and mononuclear cells. The patient died 10 months later from widespread metastases to the lung and brain. A panel of enzymo- and immunohistochemical markers reactive and osteoclastic, fibroblastic and histiocytic determinants was tested on the cutaneous lesions. The results indicated osteoclastic lineage of the multinucleate giant cells whereas the mononuclear cells showed features of fibroblastic differentiation. Cutaneous metastasis from a giant cell tumor of bone is an extraordinary event and so far has only been reported once.