Primary Bilateral Lipoma Arborescens of the Wrist: A Rare Case Report

Abstract

Background:
Lipoma arborescens (LA) is an uncommon benign synovial disorder characterized by villous lipomatous proliferation of the synovium. It most frequently affects the knee; involvement of the wrist is distinctly rare and may be misdiagnosed as ganglion cyst, tenosynovitis, or other synovial proliferative conditions. Primary LA is typically described in younger patients without underlying degenerative or inflammatory arthropathy. We report an exceptionally rare presentation of primary bilateral wrist LA.
Case Report:

A 30-year-old man presented with a gradually progressive, painless-to-intermittently painful swelling over the dorsal aspect of the right wrist for 2 years. There was no antecedent trauma or systemic symptoms. He had undergone excision of a similar lesion from the left wrist 3 years earlier, suggesting bilateral disease. Examination showed a soft, lobulated, non-tender dorsal wrist mass with
painful limitation of extension. Wrist radiograph showed no arthropathy or bony abnormality. The lesion was excised under regional anesthesia and found to be a well-encapsulated yellow, lobulated villous fatty synovial mass which was completely removed while preserving extensor tendons and retinaculum. Histopathology demonstrated villous synovial hypertrophy with subsynovial mature
adipose tissue and lymphoid follicles; immunohistochemistry (CD3/CD20 negative, reactive Ki-67 pattern) excluded lymphoproliferative pathology confirming LA. Postoperatively, recovery was uneventful with restoration of painless wrist extension. The patient remains under follow-up for recurrence.
Conclusion:

Primary LA of the wrist is rare and may present with bilateral involvement. Characteristic intraoperative appearance and histopathology along with immunohistochemistry enables the diagnosis. Complete excision yields excellent functional outcomes. Regular follow-up and surveillance is recommended given limited evidence on recurrence in small-joint LA.