title: Tumor formation in Hoffa's infrapatellar fat: Case report.
abstract: Although tumors or pseudotumoral lesions are rare in the infrapatellar fat, they may affect it. Osteochondroma is the commonest benign bone tumor. However, extraskeletal presentations are rare. There are three extraskeletal variants of osteochondroma: synovial chondromatosis, para-articular chondroma and soft-tissue chondroma. We present a case of a single intra-articular lesion in the area of Hoffa's fat, in a 78-year-old female patient with a complaint of progressive knee pain associated with severe arthrosis. From the clinical and radiological findings, the diagnosis was para-articular osteochondroma. However, the histopathological findings, after excision of the lesion, showed that this was synovial chondromatosis secondary to osteoarthrosis.
authors.affiliation: National Institute of Traumatology and Orthopedics, Rio de Janeiro, RJ, Brazil.
authors.forename: Alan de Paula
authors.initials: Ade P
authors.lastname: Mozella
authors.affiliation: National Institute of Traumatology and Orthopedics, Rio de Janeiro, RJ, Brazil.
authors.forename: João Victor
authors.initials: JV
authors.lastname: da Silveira Moller
authors.affiliation: National Institute of Traumatology and Orthopedics, Rio de Janeiro, RJ, Brazil.
authors.forename: Hugo Alexandre
authors.initials: HA
authors.lastname: de Araújo Barros Cobra
keywords: Adipose tissue; Osteochondroma; Synovial chondromatosis