Lipoma Arborescens : Pathogenesis & Differential
Pathogenesis: The etiology of lipoma arborescens is still unclear. The most accepted hypothesis is that it is a non-specific reaction to chronic synovial irritation caused by minor trauma, chronic inflammatory or degenerative joint diseases, neoplasms, and even infections. Many cases occur without any predisposing factors. Lipoma is a misleading term for this condition as it is not a neoplasm. An alternative term - villous lipomatous proliferation of the synovial membrane - has been proposed. A similar lesion affecting the infrapatellar fat pad is called Hoffa disease.Differential Diagnosis: The differential diagnosis of lipoma arborescens includes pigmented villonodular synovitis, synovial osteochondromatosis, rheumatoid arthritis, intra-articular or synovial lipoma, synovial hemangioma, amyloid arthropathy, and xanthoma.