lipom

Lipom, or lipoma in English, is a common benign tumor composed of mature adipose tissue. It most often develops in subcutaneous tissue but can arise in deeper soft tissues or internally within organs. A lipoma is typically encapsulated, slow-growing, and freely movable under the skin.

Clinically, lipomas present as soft, painless, well-circumscribed lumps. They are usually small (often 1–5 cm) but can grow larger. Deep lipomas may cause discomfort or functional limitations depending on location. Variants include intramuscular lipoma, intermuscular lipoma, and lesions with vascular (angiolipoma) or fibrous (spindle cell or pleomorphic lipoma) components.

Diagnosis is based on clinical examination. Imaging such as ultrasound or MRI helps determine size, depth, and relationship to surrounding structures, and to distinguish lipomas from malignant tumors. A biopsy or excisional biopsy may be indicated if imaging is inconclusive or if features raise concern for liposarcoma.

Treatment options depend on symptoms and cosmetic concerns. Asymptomatic lipomas may be observed. Symptomatic, enlarging, or cosmetically bothersome lipomas are usually removed by surgical excision; liposuction may be used in selected cases. Recurrence is uncommon after complete excision, though deeper intramuscular lipomas have a higher recurrence risk.

Prognosis is excellent. Lipomas are the most common benign soft-tissue tumors in adults, typically appearing in middle age with no strong sex predilection. A rare hereditary form called familial multiple lipomatosis can occur.

Etymology: the term derives from Greek lipos “fat” and -oma “tumor.”