Synovial lipomatosis arborescens of the peroneal tendon sheath.

The term "lipoma arborescens" has been used to describe the diffuse infiltration of fat within hypertrophic synovial villi, a condition which has been most frequently described in the knee. We advocate the term "synovial lipomatosis arborescens" for this process and present what is, to our knowledge, the first reported case of this disorder isolated to the peroneal tendon sheath, with imaging, intraoperative, and histological correlation.