Primary giant cell tumor of soft tissues - A study of 22 cases

Twenty-two cases of giant cell tumor of soft tissues (GCT-ST) identified in the Mayo Clinic files and the consultation files of two of the authors (A. G.N,, C.D.M.F.) were analyzed clinicopathologically. Age at presentation ra nged from 5 to 80 years (median, 43 years), and there was no sex predilecti on(12 male, 10 female). Duration of symptoms ranged from 2 to 12 months (me dian, 4.5 months), and a painless growing mass was the most common complain t. The lower limbs were the most frequent location (50%), followed by the t runk (31.8%) and the upper limbs (13.6%). The size of the tumors ranged fro m 1 to 10 cm, and they tended to be superficial (86.4%), forming well-circu mscribed (72.7%), multinodular (86.4%) masses. Histologically, all tumors c onsisted of a mixture of mononuclear cells showing vesicular, round to oval nuclei and osteoclastlike, multinucleated giant cells distributed uniforml y throughout the tumors. Foci of stromal hemorrhage were observed in 11 tum ors (50%); nine tumors (40.1%) showed metaplastic bone formation and six (2 7.2%) showed aneurysmal bone cystlike areas. Necrosis was absent in all but one tumor. Mitotic figures were present in all but one tumor, ranging from two to more than 30 mitoses per 10 high-power fields (HPFs median, 9.5 mit oses per 10 HPFs) and were typical in aspect. Vascular invasion was identif ied in seven tumors (31.8%), and none of the tumors showed marked cellular atypia or pleomorphism. The tumors were treated surgically, and follow-up i nformation was available for 16 patients (duration of follow-up, 2 to 130 m onths; median, 51 months). Only one of the 16 patients (6.2%) had local rec urrence and lung metastases; this patient died of the tumor. In conclusion, GCT-ST occurs as a primary soft-tissue neoplasm and is identical clinicall y and morphologically to giant cell tumor of bone. Provided that GCT-ST is treated adequately by complete excision, a benign clinical course is expect ed because episodes of distant metastasis and tumor-associated death seem t o be exceedingly rare.