Primary giant cell tumor of soft tissues similar to bone giant cell tumor:A case report and literature review

In this report we describe a primary giant cell tumor (GCT) of soft tissues located in the left dorsal wrist of a 52-year-old man. Plain radiographs d id not reveal any lesion in his carpal or hand bones. Although the tumor wa s clinically considered a ganglion initially, the microscopic features were identical to those found in classic GCT of bone. Light microscopy showed a lesion composed of a homogeneously mixed proliferation of spindle and poly gonal mononucleated stromal cells and evenly distributed multinucleated, os teoclast-like giant cells. Whereas most bone tumors have an extraosseous co unterpart, only 13 cases of GCT in soft tissues had been published until 19 98. Moreover, 64 new cases have been reported in three series. Nevertheless , most major reviews and textbooks do not consider this tumor as a specific entity and regard it as a low grade variant of malignant GCT of soft tissu e. We describe the clinical, histologic, and immunohistochemical features o f this rare benign neoplasm emphasizing the differential diagnosis with its malignant soft tissue counterpart, an ominous tumor.