Zellweger syndrome: a histochemical diagnosis of two cases.

Until 17 years ago the diagnosis of the cerebrohepatorenal Zellweger syndrome (ZS) rested largely on clinical grounds confirmed by pathologic findings at autopsy. The observation that peroxisomes are not detectable morphologically or histochemically in liver or kidney of patients with this syndrome gave histopathologists the opportunity to make the diagnosis of this complex syndrome at biopsy. Catalase reaction of the peroxisomes can be used as a rapid and accurate method to differentiate between ZS and other clinical conditions in which the peroxisomes are present in normal or reduced number. We describe two patients in whom the diagnosis of ZS was made by the absence of histochemical staining for catalase in a liver biopsy. The findings were subsequently confirmed using standard biochemical tests.