OCHRONOSIS 473 



Ochronosis -^ is a condition characterized by a black pigmentation 

 of the cartilages, first described by Virchow in 1866. In 1904 Osier ^'' 

 reported two eases, and fonnd bnt .seven others in the literature to 

 that time. The origin and nature of tliis pigment remains still un- 

 decided. Virchow suspected that the condition was due to a permea- 

 tion of cartilage by hematin derivatives, but Hansemann, finding a 

 case associated with melanuria, considered that the pigment is prob- 

 ably of metabolic origin. Ilecker and AYolf studied the urine of a 

 similai' case, and concluded that the pigment must be melanin. Al- 

 brecht,-^ however, suggested a relation of ochronosis to alkaptonuria, 

 having found homogentisic acid in the urine of a case reported by 

 him (see "Alkaptonuria"). Osier's two patients were brothers with 

 alkaptonuria, the evidence of ochronosis consisting of discoloration of 

 the cartilages of the ears. Langstein -** has examined a specimen of 

 urine preserved from Hansemann 's case, and found no evidence of 

 alkaptonuria.'" 



Pick ^'^ summarizes the results of his study of his case and of the 

 literature, as follows : Ochronosis is a definite form of melanotic pig- 

 mentation, the pigment of ochronosis being in most of the cases very 

 closely related to melanin. The pigment, or its chromogen, circulat- 

 ing freely in the blood, is imbibed not»only by cartilage, but also by 

 loose connective tissue, voluntary and involuntary muscle-cells, and 

 epithelial cells, without any decrease in vitality of these cells being 

 observable ; however, degenerated tissues show the greatest amount of 

 pigmentation. The diffuse pigment can become granular after a time ; 

 it is iron-free, but under certain circumstances may contain fat. 

 Thi^ melanin arises from the aromatic nucleus of the protein mole- 

 cule (tyrosine, phenylalanine), and the related hydroxylized products, 

 binder the influence of tyrosinase. In some cases the constant ab- 

 sorption of minute quantities of phenol from surgical dressings seems 

 to have been the cause of the condition. Besides this formation of 

 pigment from such "exogenous" aromatic substances, however, it is 

 probable that in alkaptonuria the "endogenous" aromatic substance 

 (homogentisic acid) present may be converted into pigment by the 

 tyrosinase. In many of the cases of ochronosis the pigment or a 

 precursor may be excreted in the urine, which then undergoes spon- 

 taneous darkening when exposed to the air. The kidneys may also 

 become pigmented and granular masses of pigment may be present 

 in the renal tubules. . 



25 See Adler, Zeit. f. Krebsforsch., 1911 (11), 1: Poulsen, Ziegler's Beitr., 1010 

 (48). 346. 



26 Lancet. 1004 (i), 10 (literature). 



27 Zeit. f. Heilk., Path. AM., 1002 (2.3), 366. 

 2s Hofmeister's Beitr., 1003 (4), 145. 



20 Also see Langstein. Berl. klin. Woch.. 1006 (43), 507. 

 30Berl. klin. Wochenschr., 1906 (43), 478. 



