Abstract

Extraskeletal osteosarcoma is a rare high grade malign mesenchymal tumor with osteoid, bone and chondroid matrix.It accounts for 1.2 % (1)of all soft tissue tumors and less than 4 % of osteosarcomas (2,13).The tumor occurs principally in soft tissue of retroperitoneum and extremities without any attachment to the underlying bone and periosteum.In contrast to the other subtypes of osteosarcoma which is seen in the first two decades, ESOS most commonly occurs in patients over 40 years old. Breast, skin, bladder, lung and mediastinum, tongue, spermatic cord and penis, cerebrum and colon are other extraordinary localisations of ESOS (3-12).Histopathologically the tumor showed proliferation of epithelioid and spindle shaped tumor cells focally forming lace like osteoid material. Therefore, a definite diagnosis of ESOS was made.