Extraskeletal ossifying chondroma in Hoffa's fat pad: an unusual cause of anterior knee pain.

Hoffa's disease is an obscure cause of anterior knee pain. A misconception about its rarity is very common among clinicians, and hence it is often misdiagnosed and treated as meniscal pathology. Increased awareness is required to diagnose and treat the condition appropriately. These diagnostic uncertainties commonly result in increased patient morbidity and mismanagement. In spite of a widely-accepted common occurrence of Hoffa's disease, ossification of the Hoffa's fat pad is seldom reported. We report a giant extraskeletal ossifying chondroma in a 55-year-old man, presented as chronic knee pain and successfully treated by excision. The anatomy, pathology, histology, radiological features and management of the disease are described, to increase awareness in the orthopaedic community of this common, interesting but rarely discussed condition.