Ochronotic Arthropathy: A Report of Two Cases

Abstract

Ochronosis is an entity characterized by deposition of homogentisic acid and metabolites in connective tissues, such as joint cartilage, skin and sclera. Ochronosis is generally diagnosed by a clinical triad of degenerative arthritis, ochronotic pigmentation and urine color turning black upon alkalization. Since ochronotic arthropathy is one of the most important morbidity causes in ochronosis, in this study, we aimed to present two cases diagnosed. One of two cases we present had advanced degenerative alterations in both hip and knee, and the other case had advanced degenerative alterations in knee joints. Macroscopical examination of the resection materials revealed black pigmentation on joint surfaces. Histopathologically, cartilage lacunes filled with brown pigment and inflammatory infiltration, as well as brown pigmentation in soft tissue, were observed. Clinical history revealed that the patients had dark urine since childhood and they detected dark spotting at their underwear. As all findings evaluated together, these two rare cases, which are diagnosed as ochronotic arthropathy, reviewed in the light of the literature.

Keywords

• degenerative arthritis
• hip joint; knee joint; ochronotic arthropathy; pigmentation.