fibrolipoma

Fibrolipoma is a benign neoplasm that represents a histologic variant of lipoma, consisting of mature adipose tissue embedded in dense fibrous stroma. It usually presents as a slow-growing, painless subcutaneous or intramuscular mass in adults. The lesion is often soft but may feel firmer because of the fibrous bands; commonly found in the trunk, limbs, head and neck, or oral cavity.

Histologically, fibrolipoma shows adipocytes arranged in lobules separated by thick fibrous septa. There is no cytologic atypia or lipoblasts and mitotic activity is absent. The finding distinguishes it from liposarcoma on pathology, though biopsy is used when imaging is inconclusive.

Imaging typically reveals a fat-density lesion with internal fibrous strands on CT or MRI; on MRI the mass often has high signal on T1- and T2-weighted sequences with septa that enhance after contrast. Definitive diagnosis is by histopathology.

Management is surgical excision. Recurrence is uncommon, usually related to incomplete removal. The prognosis is excellent, and malignant transformation has not been reported.

Fibrolipoma is a recognized histological variant of lipoma and is sometimes called fibrous lipoma. It occurs most commonly in adults; pediatric cases are rare.