Multicentric giant cell tumor of the fourth and fifth metacarpals with lung metastases.

Giant cell tumors of bone (GCTB) are generally benign neoplasms, but recently, some authors consider them to be low-grade malignant neoplasms because they have a relatively high rate of recurrence and at least some potential for metastases. The majority of GCTB are unifocal, and less than 1 % are multicentric. We report a rare case of a multicentric GCTB arising simultaneously in the non-dominant fourth and fifth metacarpals of a 25-year-old female. The patient underwent ray amputation of the two involved digits, and the surgical margins were histologically negative for tumor. The tumor had the classic histologic appearance of a benign GCTB. A year after the amputation, the patient developed pulmonary metastasis which was treated with pulmonary lobe resection. She is currently over 2.5 years postsurgical treatment of the primary lesion with no evidence of local recurrence or distant metastasis.