Well-differentiated liposarcoma. The Mayo Clinic experience with 58 cases.

The clinicopathologic results from 58 patients with well-differentiated liposarcomas are reported. Thirty-two tumors involved the extremities, 20 the retroperitoneum, 4 the scrotum, 1 the abdominal wall, and 1 the cheek. Most tumors were large (mean, 22.6 cm). There were 31 (53%) lipoma-like, 23 (40%) sclerosing, and 4 (7%) primary dedifferentiated tumors. Six tumors underwent dedifferentiation after recurrence. The average follow-up period was 9.3 years. Thirty-seven patients (64%) were alive with no evidence of disease; 7 (12%) were alive with disease; 8 (14%) died of disease; and 6 (10%) died of other causes. Dedifferentiation did not indicate imminent death; 5 of the 10 patients were alive with no evidence of disease. Three dedifferentiated tumors subsequently recurred as pure well-differentiated liposarcomas. Patients with extremity tumors had a significantly better prognosis than those with retroperitoneal or scrotal tumors (P = .006). Extremity tumors treated by wide local excision recurred in only 11% of cases, whereas 60% of those treated by marginal or simple excision recurred.