Ochronosis of the hip joint: differential diagnosis of inflammatory arthropathy with lytic lesion.

Alkaptonuria or ochronosis is a rare inborn disorder of metabolism which is characterized by deficiency of homogentisic acid oxidase. There is accumulation of homogentisic acid in the connective tissues causing brownish black pigmentation and skeletal damage. The most serious complication of this disease is crippling degenerative arthropathy which presents in late years of life. There is no definitive treatment for the condition. Symptomatic management is the main stay. Surgical management such as arthroplasty is done for severe cases of ochronosis. We report a case of ochronosis of the hip joint presenting with inflammation and lytic lesion which can create confusion and lead to error in diagnosis.