Special stain and X‐ray probe microanalysis of livers with Wilson disease

AIM: Primary copper toxicosis due to Wilson disease is clinically complex, often leading to delayed diagnosis. Because the metabolic disorder is frequently complicated by iron overload due to hypoceruloplasminemia, either a special stain or microanalysis has been recommended for liver biopsy specimens. METHODS: Liver biopsy was performed in three patients in whom Wilson disease was highly suspected. Light microscopic study included rubeanic acid stain for copper and Berlin blue stain for iron. To improve the resolution of ultra-structures and preservation of toxic metals, short-term fixation with a 0.1% osmic acid solution was applied for X-ray probe microanalysis. Their diagnosis was confirmed by genetic study and copper chelation therapy. RESULTS: Two patients at the age of 17 and 23 years, respectively, demonstrated cirrhotic livers surrounded by fibrous septa, while a 7-year-old patient demonstrated fatty liver with mildly expanded portal tracts. Both copper grains stained with rubeanic acid and cuprothionein by microanalysis were found in the cirrhotic livers of aged patients. However, either morphological method failed to detect copper deposition in fatty liver tissues from the young patient. Iron deposits were also found in the cirrhotic livers of aged patients. The molecular basis of Wilson disease was confirmed by gene analysis. All patients responded to copper chelation therapy. CONCLUSION: A morphological method of special staining or microanalysis improved with a new fixative may be unreliable for detecting diffusely distributed copper in the early stage of Wilson liver disease.