Atypical lipomatous masses of the extremities: outcome of surgical treatment.

Atypical lipomatous tumors occur predominantly in middle-aged patients and often present as painless, slow-growing masses in the extremities. The clinical outcomes of surgically treated superficial or deep atypical lipomas of the extremities were reviewed. Thirty-one patients were included in this study. There were 16 men and 15 women, with an average age of 57 years (range, 32-87 years). The mean followup was 7 years (range, 1-28.8 years). Twenty-five tumors occurred in the lower extremity and six in the upper extremity. Sixteen patients (52%) had a recurrence at an average of 4.7 years after resection. Twelve (39%) patients required additional surgical procedures to treat their tumor. Occurrence of a deep lesion and positive margins at the time of the initial surgery correlated closely with the rate of recurrence and need for additional surgical treatment. Dedifferentiation to high-grade liposarcoma developed in four (13%) patients. Atypical lipomas have a high propensity for local recurrence and a potential for malignant dedifferentiation. Patients with atypical lipomas require careful evaluation, complete surgical excision when possible, and close clinical followup extending beyond 5 years.