Lipomas Differential Diagnoses

Updated: Apr 29, 2022
  • Author: Todd A Nickloes, DO, FACOS; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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Diagnostic Considerations

Lipomas must be differentiated from other masses or tumors.

In the subcutaneous location, the primary differential diagnosis is a sebaceous cyst or an abscess. Sebaceous cysts are also rounded and subcutaneous; they originate in the dermis and reside within the skin at the dermal-epidermal junction. These cysts can be differentiated from lipomas by their characteristic central punctum and the surrounding induration. Treatment requires removal of a small ellipse of overlying skin to avoid entering the cyst. Abscesses typically have overlying induration and erythema. Incision and drainage is the appropriate management.

Hibernomas are uncommon tumors that arise from brown fat. They are also benign but with a slightly greater tendency to bleed during excision and to recur if intralesional excision is performed.

Atypical lipomatous tumors are considered to be well-differentiated liposarcomas. They have a predilection for local recurrence but do not generally metastasize. This diagnosis should be suspected when a fatty tumor is encountered in an intramuscular or retroperitoneal location.

Liposarcomas are malignant tumors that arise from adipocytes. They may recur locally and may metastasize. Fatty tumors of the retroperitoneum or in intramuscular locations should be considered to be potential liposarcomas until proven otherwise.

In the breast, a lipoma will be mammographically radiolucent. It must be differentiated from a similar benign tumor, a mammary hamartoma, and a pseudolipoma (a soft-tissue mass that may surround a small, scirrhous cancer).

Conversely, lipomatous lesions in the adrenal gland that have calcifications on radiologic examinations have been confused with teratoma. Many of these are angiomyolipomas.

In the spermatic cord, a finger of retroperitoneal fat termed a "lipoma of the cord" is frequently encountered during hernia repair. Removal is advocated to allow the internal inguinal ring to be tightened around the cord and to minimize the risk of recurrence of the hernia. During laparoscopic exploration for a palpable inguinal mass, no identifiable peritoneal orifice may be found if the inguinal mass purely consists of a lipoma of the cord.