[Giant cell tumor of bone with rapid malignant course].

The case of a 28-year-old male patient with a locally aggressive lesion of the distal tibia is presented. Following the diagnosis of giant cell tumor of bone (GCT) on biopsy and curettage, a rapid malignant course was observed with recurrence 2.5 months later. Multiple metastases appeared 6 months after initial presentation. Following initial chemotherapy according to the COSS protocol and later with carboplatin and VP-16, therapy was changed to Adriamycin and later gemcitabine due to progressive disease. Good palliation was achieved, and the patient felt well with less shortness of breath on exertion and was ambulatory with walking aids. The malignant nature of the tumor was not detected in the initial pathologic examinations. Review of the pathologic material provided histologic clues permitting the diagnosis of a primary malignant GCT with a fibrohistiocytic/fibrosarcomatous component. Malignancy in a giant cell tumor is a much debated diagnostic dilemma when a frank sarcomatous component is lacking. Cytologic atypias and flame-like tufts of infiltration of soft tissue are important clues. Surgical treatment should be commensurate. Monotherapy with Adriamycin or gemcitabine can be considered in order to inhibit the disease progression.