Pseudo-tumor of the calf.

The differential diagnosis of calf swelling includes deep venous thrombosis (DVT), ruptured popliteal (Baker's ) cyst, infection, sarcoma and hematoma. Bony erosion is seldom seen in benign conditions and, when present, usually indicates tumor involvement. 'Pseudosarcoma', where hematoma may mimic sarcoma, has been described in hemophiliacs. A case is described of pseudosarcoma with bone erosion occurring as a complication of anticoagulant therapy, a clinical situation not reported previously.