Giant cell tumor of soft tissue: GCT arising from periosteum of tibia.

Primary Giant Cell Tumor of Soft Tissue (GCT-ST) is a rare disease, a neoplasm with low potential for malignancy. It belongs to the group of Fibrohistiocytic tumors with borderline malignancy. Most commonly it presents as a painless, slow-growing mass in a superficial location. It is associated with lower local recurrence rate as compared to GCT of bone but has a higher rate for metastasis and mortality. A case of rare GCT-ST with suspicion of lung metastasis is being reported here. The lesion per-operatively appeared to be growing from the periosteum of the bone (tibia in our case). After excisional biopsy it proved to be GCT-ST which has never been reported previously in literature.