A pleomorphic lipoma usually occurs in the neck, the shoulder, and/or on the backs of men over the age of 50. This tumor displays a mixture of fat cells, pleomorphic cells, floret cells, and bundles of mature collagen fiber. Herein we report on a pleomorphic lipoma that occurred on the palm of a 56-year-old woman. An immunohistochemical study, performed to compare the characteristics of a pleomorphic lipoma with those of a spindle cell lipoma, has suggested that the pleomorphic and floret cells of a pleomorphic lipoma are similar to the spindle cells of a spindle cell lipoma and not to fat cells. Our result seems to indicate that these two tumors are on the same spectrum and only the quantity of the pleomorphism keeps them distinct.

Pleomorphic lipoma of the face: case report.Oral Dis. 2006 Jan;12(1):73-6.

Pleomorphic lipoma is an uncommon variant of lipoma, which microscopically may resemble a liposarcoma. However, it is a slow-growing and well-circumscribed lesion with a benign behavior. Therefore, recognizing this entity is extremely important to perform the proper treatment. We present an additional case of pleomorphic lipoma in the face, which to our knowledge seems to be the 11th case reported in the English-language literature.

Pleomorphic lipoma: case report and literature review.Dermatol Surg. 2000 Apr;26(4):375-80.

BACKGROUND: Pleomorphic lipoma is a rare, benign, pseudosarcomatous, soft tissue neoplasm typically involving the subcutis of the neck and shoulder in middle-aged to elderly men. It is characterized histologically by atypical, multinucleated giant cells and grossly as a well-circumscribed mass. Since this neoplasm can resemble a sarcoma, histopathologic diagnosis is critical in preventing unnecessary surgery. OBJECTIVE: To describe a case of pleomorphic lipoma in the neck and to review the clinical and histopathologic characteristics of this neoplasm. METHODS: We present a case report and review of the literature. RESULTS: Local excision to completely extirpate this neoplasm has proven curative at 10 months of follow-up. CONCLUSION: Pleomorphic lipoma is superficially located and may be encountered in a dermatologic setting. Thus the dermatologist should become familiar with its clinical presentation and microscopic appearance.