Cutaneous lipomatous neoplasms

Benign and malignant lipomatous tumors are the most common neoplasms of sub cutaneous and deep soft tissues in adults. In contrast, purely cutaneous li pogenic neoplasms are exceptionally rare, and some entities and variants of adipocytic neoplasms have not yet been described in the skin. In addition, some dermal lipogenic neoplasms are characterized by different specific cl inicopathologic features in comparison with more deeply located tumors. Cut aneous angiolipoleiomyoma ("angiomyolipoma") is seen most often in male pat ients and in an acral location. It is characterized histologically by matur e adipocytes, thick-walled blood vessels, and smooth muscle cells arranged in well-defined fascicles and around blood vessels. Smooth muscle cells in cutaneous angiolipoleiomyoma stain negatively for HMB-45, in contrast to re nal and extrarenal angiomyolipoma. Adenolipoma of the skin is a superficial ly located form of lipoma composed of large lobules of mature adipocytic ti ssue admixed with eccrine ducts and glands. Cutaneous spindle cell/pleomorp hic lipomas, in contrast to subcutaneous forms, are more common in female p atients and have a wide anatomic distribution. Histologically, cutaneous sp indle cell/pleomorphic lipomas are characterized by an infiltrative growth pattern mimicking more aggressive lesions. Rarely, liposarcoma may occur as a purely cutaneous lesion with a favorable clinical prognosis despite high -grade morphologic features in many cases. Copyright (C) 2001 by W.B. Saund ers Company.