[Multiple histochemical methods in the diagnosis of Wilson's disease. (Presentation of 74 cases and review of the literature)].

Conflicting results have been reported on the usefulness of histochemistry for copper in the diagnosis of Wilson's Disease (W.D.). In spite of the high number of methods proposed in the literature, no-one has shown to have the characteristics typical of a good histochemical method: high sensitivity associated with high specificity. On this basis, it seemed of interest to evaluate, in a large series of patients with W.D., the diagnostic value of the most commonly used histochemical methods for copper (rhodanine, orcein and Timm's method). To this end, 74 liver needle biopsies from patients affected by W.D., 39 males and 35 females, aged 4-60 years (mean age 28.5 years), were stained with rhodanine (R), orcein (O) and Timm's (T) methods. On the basis of the histological picture, liver biopsies were subdivided in four evolutive stages: stage I = steatosis; stage II = interface hepatitis; stage III = bridging fibrosis; stage IV = cirrhosis. In stage I, histochemistry for copper was positive in 11 out of 21 cases: 6 cases were T+; 1 case R+ and 2 cases O+; 2 cases were T+, R+, O+. In stage II, 11 out of 14 cases were positive for copper staining: 4 T+, 2 R+ and 2 O+; 3 cases were contemporary positives for T, R, O. In stage III, 22 out of 25 cases resulted positive: 8 T+, 3 R+ and 1 O+; 10 cases were positives, in the mean time, for more of one method. In stage IV, 12 of 14 cases were positives: 5 T+, 2 R+, 2 O+ and 3 cases were contemporaneously positives for multiple methods. Our data show that: 1) the percentage of positivity obtained using three histochemical methods for copper is higher than using only one method. From a practical point of view, it is mandatory to utilize, in clinical practice, multiple histochemical stains in order to increase the diagnostic utility of histochemistry for copper; 2) the Timm's method appears to be the most sensitive method for the demonstration of copper in all stages of W.D.; 3) even though hepatic copper already abounds in the early stages of W.D., this pool of intrahepatic copper is not yet demonstrable with any of the three histochemical techniques utilized.