Lipoma arborescens in the dorsum of the hand: a case report and a comprehensive review.

Lipoma arborescens is a rare synovial disorder, typically affecting the knee joint, with limited reports of atypical presentations. The study emphasizes the need for a multidisciplinary diagnostic approach and discusses the genetic and signalling factors associated with its pathogenesis. A 50-year-old male presented with a painless swelling in the dorsum of the right hand, a rare extra-articular manifestation of Lipoma arborescens. Comprehensive clinical, imaging, and histopathological evaluations confirmed the diagnosis, revealing unique features on MRI and frond-like fatty tissue infiltration on excisional biopsy. The case underscores the distinct clinical characteristics, diagnostic challenges, and differential considerations associated with atypical Lipoma arborescens presentations. Extra-articular manifestation of Lipoma arborescens involving the dorsum (extensor aspect) of the hand is rare. Imaging techniques, including MRI and ultrasound, play a crucial role in accurate diagnosis, differentiating it from other joint pathologies. The MRI findings include intra-articular fat deposits and villous proliferation of the synovial membrane. At the same time, the histopathological analysis includes frond-like infiltration of sub-synovial tissue with mature adipocytes which helps in confirming the diagnosis. Successful surgical excision of the extra-articular lesion highlights the importance of a comprehensive diagnostic strategy for managing this uncommon condition. The study contributes valuable insights into understanding, diagnosing, and treating atypical presentations of lipoma arborescens.