Intra-articular neurofibroma: an unusual source of anterior knee pain.

The infrapatellar fat pad of the knee is often implicated as a source of anterior knee pain. We present an unusual case of anterior knee pain in an adult patient from a solitary neurofibroma arising in an intra-articular location associated with the infrapatellar fat pad. Clinical, radiographic, magnetic resonance imaging (MRI), and histopathologic features are presented, as well as, a review of the literature. This case adds to the differential diagnosis of fat pad lesions seen on MRI and contributes to understanding the spectrum of clinical presentations of neurofibromas and pathology involving this region.