HEPATIC GRANULOMAS FOLLOWING LIVER-TRANSPLANTATION - CLINICOPATHOLOGIC FEATURES IN 42 PATIENTS

Liver granulomas have long been known to pose diagnostic problems for pathologists; however, their prevalence and associated etiologic facto rs have not been studied in liver transplant patients. We reviewed 363 2 liver biopsy specimens from 563 patients at two institutions and ide ntified 42 patients with posttransplant granulomas. A possible or prob able etiologic factor was identified in 30 (71%) cases, Most were epit helioid granulomas and microgranulomas located in the parenchyma assoc iated with hepatocyte necrosis (21 cases, 50%). Portal-based granuloma s were associated with recurrent primary biliary cirrhosis (5 cases, 1 2%), acute cellular rejection (2 cases, 4.8%), and a foreign body-type reaction (1 case, 2.4%). One case was associated with tuberculosis (2 .4%), 4 cases occurred in a fatty liver (9.5%), and 8 patients had liv er granulomas but no other significant abnormality. The granulomas wer e most frequent in the first 7 months after transplantation when the p atients were biopsied more often and underwent episodes of rejection o r acute hepatitis. Portal-based granulomas in this period were usually associated with acute cellular rejection, After 7 months, the frequen cy of granulomas as well as the number of biopsies decreased and porta l-based granulomas associated with recurrent primary biliary cirrhosis were most common (5 cases, 12%). Rare, late-appearing parenchymal gra nulomas were also seen (3 cases) and consisted of 1 Lipogranuloma and 2 cases of epithelioid granuloma. The latter were thought, in 1 patien t, to be associated with parenchymal hepatocyte necrosis; the others w ere of unknown etiology.