title: Black joint and synovia: Histopathological evaluation of degenerative joint disease due to Ochronosis.
abstract: BACKGROUND
  Ochronotic arthropathy is a rapidly progressive and disabling arthropathy predominantly encountered after the fifth decade of life, caused by homogentisate1,2 dioxygenase enzyme deficiency. As it is rare disease, the literature on histological findings is fragmented.
  
  
  METHODS
  We retrospectively re-evaluated histopathological findings in resection and/or curettage materials (5 hip joint, 4 knee joint, one hip joint synovium, one intervertebral disk and one paravertebral disk tissue) of seven ochronosis cases diagnosed between 1995 and 2013 in a single center.
  
  
  RESULTS
  Necrotic brown chondroid detritus was present in all cases either in synovia or in subchondral area, some of which evoked giant cell reaction. Notably, brown pigmentation was prominent in upper middle parts of the articular cartilage but not that prominent in superficial parts and in osteochondral junction, almost stopping at the tide mark. Pigmentation was observed both in extracellular matrix and in cytoplasm either in granular or homogeneous fashion. Depositions were less prominent in osteophytic processes, regenerated cartilaginous areas and loose bodies. Almost all cases showed synovial detritic and inflammatory reaction, fibrillation, eburnation, and subchondral sclerosis. Disk degeneration and findings of ligament rupture were also observed.
  
  
  CONCLUSIONS
  Histopathological diagnosis of ochronosis is not complicated given the unique "black coloring" of the affected tissues and it can easily be differentiated from other causes of detritic synovitis both clinically and histopathologically. However, there is no definitive cure for today and the reasons for late onset of arthropathy in disease course, and the mechanisms of tissue reaction to fragmented detritus remain elusive.
authors: Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey. Electronic address: bdoganavsargil@yahoo.com.
authors: Basak
authors: B
authors: Doganavsargil
authors: Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey.
authors: Burcin
authors: B
authors: Pehlivanoglu
authors: Ege University Faculty of Medicine, Department of Orthopedics, Izmir, Turkey.
authors: Elcil Kaya
authors: EK
authors: Bicer
authors: Ege University Faculty of Medicine, Department of Radiodiagnostics, Izmir, Turkey.
authors: Mehmet
authors: M
authors: Argin
authors: Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey.
authors: Kenan Baris
authors: KB
authors: Bingul
authors: Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey.
authors: Murat
authors: M
authors: Sezak
authors: Ege University Faculty of Medicine, Department of Orthopedics, Izmir, Turkey.
authors: Burcin
authors: B
authors: Kececi
authors: Ege University Faculty of Medicine, Department of Paediatric Endocrinology and Metabolism, Izmir, Turkey.
authors: Mahmut
authors: M
authors: Coker
authors: Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey.
authors: Fikri
authors: F
authors: Oztop
mesh_terms: D000368:Aged; D044383:Black People; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009794:Ochronosis / Q000175:diagnosis / Q000473:pathology*; D010003:Osteoarthritis / Q000175:diagnosis / Q000473:pathology*; D013582:Synovial Fluid / Q000378:metabolism*; D013583:Synovial Membrane / Q000473:pathology
keywords: Alkaptonuria; Degenerative joint diseases; Ochronosis; Ochronotic arthropathy; Synovitis