Multifocal intraarticular lipoma arborescens of the hip and knee: A case report and review of literature

Abstract

Lipoma arborescens (LA) is a rare clinical condition presenting mostly as an intra-articular lesion characterized by villous proliferation of the synovial membrane and hyperplasia of sub synovial fat. We report a case of a multifocal LA localized in the knees and the hips in a 20-year-old man symptoms being present for the last 3 years and initially mimicking an inflammatory arthropathy. On physical examination a discreet joint swelling of the left knee with effusion, and limited movements in the left hip were observed. Laboratory tests presented normal acute phase reactants of inflammation as well as the rheumatoid factor, CK, and negative results for antinuclear and anti-CCP (ELISA) antibodies. Magnetic resonance imaging of the knees and hips showed articular effusion and synovitis, and a pattern of LA. The histopathologic study confirmed the diagnosis. Arthroscopic synovectomy for the knee and open synovectomy for the hip brought some improvement to joint mobility and pain.Although rare, this condition must be differentiated from inflammatory arthropathy, particularly in the absence of response to clinical treatment, and absence of positive biochemical markers, since the therapeutic strategy is radically different.