Synovial lipomatosis of the metatarsophalangeal joint: A case report.

Synovial lipomatosis, also termed lipoma arborescens, is an extremely rare disorder of the synovium that causes joint pain, swelling and effusion. To date, only a small number of cases have been reported in the literature. The current study presents the case of a 44-year-old male with repeated swelling of the metatarsophalangeal joints of the left hallux, which had persisted for ~3 years. The main clinical manifestations on presentation included multiple osseous lumps and limited activity of the left hallux without pain. Magnetic resonance imaging of the left hallux revealed a mass surrounding the left metatarsophalangeal joints. Subsequently, the lesion was resected. Pathological examination revealed well-defined lobules of mature adipocytes separated by thin fibrous septa, which indicated a diagnosis of synovial lipomatosis of the metatarsophalangeal joint of the left foot. The aim of this study was to evaluate synovial lipomatosis of the metatarsophalangeal joint, with an analysis of the clinical parameters and pathological features of the disorder.