Lipoma arborescens is a  condition affecting synovial linings of the joints and bursae, with 'frondlike' depositions of fatty tissue.

The macrospic frondlike appearance was felt to resemble a tree in leaf; hence, the Latin term arborescens (meaning “tree-forming” or “treelike”).

It is most often observed in those over 50 years or age with recurrent effusions, most commonly in the knee, but can occur in rarer circumstances, such as collagen vascular disorders.

This 18 year-old female suffered from juvenile chronic arthritis (JCA) with recurrent effusions which were blood stained on aspiration.