Hepatic granulomas: a clinicopathologic analysis of 86 cases

The aim of this study was to determine the prevalence and histopathological characteristics of hepatic granulomas. All records of liver biopsies/resections evaluated in our pathology department between 2002 and 2009 were retrospectively reviewed. Specimens with hepatic granulomas were reexamined by a designated pathologist. Type and localization of granulomas, size of granulomas and epithelioid histiocytes, and the morphological findings of surrounding liver tissue were recorded in an attempt to establish a correlation with relevant clinical, laboratory and radiological findings. Out of 1420 liver biopsy/resected specimens evaluated at our institution during the study period, 86 cases of epithelioid cell granulomas (6.05%) were observed. Of the 86 cases, 23 were men and 63 were women. The most common underlying etiology was PBC in 38 patients, infections in 34, malignancies in five, sarcoidosis in four, and foreign bodies in three patients. One case (1.2%) of a drug-induced hepatic granuloma was encountered, while another case was deemed idiopathic (of unknown etiology). Contrary to common belief, granulomas were observed not only in early stage PBC but also in cases with stage 3 disease. Out of all the PBC cases with granulomas, 55.6% had stage 3 disease, and besides periductal granulomas, intraacinar granulomas were also seen. For sarcoidosis, intra- and peri-granulomatous fibrosis was observed in as many as 75% of cases. A large majority of granulomas (82.4%) associated with infections were of the necrotizing type. Extensive evaluation of the morphological characteristics of hepatic granulomas and surrounding liver tissue along with clinical, radiological, and other laboratory findings may help arrive at an accurate diagnosis in a majority of cases. Rather than being a final diagnosis, the presence of hepatic granulomas entails the need for further investigations towards identifying the underlying etiology, with a pathologist being at the center of the diagnostic process.