In such cases, the liver can be used without any problems. In most instances, such requests can be handled over the telephone, without a frozen section by simply asking the donor's age. However, a persistent surgeon may still request that the liver be examined microscopically. In such cases, lipofuschin , which is deposited primarily in the centrilobular regions is responsible for the gross coloration. It increases with age, such that donors older than 60 years will contain enough lipofuschin to grossly affect the color of the liver.
Inexperienced pathologists can mistake lipofuschin pigment for cholestasis or iron deposits.
Iron deposits in the early stages of genetic hemochromatosis are periportal, in contrast to the centrilobular predominance of lipofuschin. Bile stasis can be distinguished from lipofuschin by the presence of pigment in the canaliculi, between the hepatocytes and bile is amorphous, whereas lipofuschin is more granular in appearance. Remembering this name is helpful in making the diagnosis. This older name also should serve as a reminder that the pathologist has to be aware that the donor liver is being evaluated for a focal lesion, so a mistaken diagnosis of cirrhosis is not made. Small firm white, well-circumscribed subcapsular nodules also frequently prompt a request for frozen section evaluation of the donor liver to rule out a primary or metastatic malignacy.