Primary liposarcoma of the skin: a rare neoplasm with unusual high grade features.

Liposarcoma is the most common soft tissue sarcoma in adults. It presents in three main forms: well-differentiated liposarcoma (which includes adipocytic, sclerosing, inflammatory, spindle cell, and dedifferentiated subtypes), myxoid/round cell liposarcoma, and pleomorphic liposarcoma. Anatomic distribution depends largely on histologic subtype, but the deep soft tissue of the extremities and the retroperitoneum are most frequently affected. Whereas it is accepted that liposarcoma rarely occurs in the subcutaneous soft tissue, the dermis seems to represent an exceedingly rare site of occurrence. The clinicopathologic features of a series of seven primary cutaneous liposarcomas (two atypical lipomatous tumors/well-differentiated liposarcomas, one myxoid/round cell liposarcoma, and four pleomorphic liposarcomas) are analyzed here. Clinically, all of the patients were adults (four men, three women) with a median age of 72 years, and four of seven cases arose on the scalp. Local recurrences occurred in two patients, but no distant metastases or disease-related deaths have been observed. Although follow-up is relatively short, it appears that, exceptionally, liposarcoma occurs primarily in the skin and, despite an apparent tendency to show high-grade morphologic features, it seems to exhibit relatively indolent clinical behavior in this location.