Dedifferentiated Liposarcoma : Microscopic Features

Comments:
Microscopic Features (continued): Most of the undifferentiated pleomorphic sarcomas (UPS), inflammatory type, arising in the retroperitoneum are dedifferentiated liposarcomas (DLPS) and will show MDM2 amplification by FISH. The inflammatory component consists of xanthoma cells, neutrophils, lymphocytes and plasma cells which may mask the pleomorphic cells in the background. The neoplastic cells are often seen phagocytizing neutrophils. The inflammatory areas usually transition to conventional storiform pattern.

DLPS resembling inflammatory UPS is frequently associated with paraneoplastic signs and symptoms such as anorexia, weight loss, fever, and leukocytosis. This is secondary to production of tumor necrosis factor, IL-6 and IL-8 by the tumor. The symptoms disappear after tumor removal.