Hepatic granulomas: a 17-year single tertiary centre experience

Aims Hepatic granulomas have an estimated prevalence of 5% in liver biopsies, with a wide range of aetiologies globally. Our aim was to assess the clinical relevance, presenting features and underlying aetiology in a non-transplant, tertiary referral centre from a western country. Methods and results This was a retrospective, single-centre review of clinical, laboratory and histological data including all adult patients for whom a liver biopsy was performed from January 1998 to December 2014. A total of 297 cases with hepatic granulomas were found in 9374 biopsies, but 57 were excluded from analysis either because they were lipogranulomas or the biopsy/aetiological work-up had not been performed at our institution. Overall, the most common aetiology was tuberculosis (35.8%), followed by primary biliary cholangitis (PBC) - 15.0%. In 30 patients (12.5%) granulomas were classified as idiopathic. From 1998 to June 2006 there were 147 granulomas in 5304 biopsies (2.8%), a frequency that did not change significantly compared to the period from July 2006 to December 2014 (93 granulomas in 4070 biopsies, 2.3%, P > 0.05). However, for the majority of cases (61.9%) there was a shift in granuloma aetiology during the former time-period that infectious diseases were responsible, whereas in the latter, autoimmune liver diseases (43%) were the main aetiology. In addition, while three cases of drug-induced granulomas were found from 1998 to June 2006, we report two cases in the second time-period. Conclusions Hepatic granulomas can result from various infectious and non-infectious diseases. During recent years, an epidemiological shift regarding granuloma aetiology was observed, from systemic infectious diseases to non-infectious, mainly immune-mediated primary liver disorders. With an appropriate work-up the aetiology can be identified in the vast majority of cases (~90%), rendering its histological identification and characterisation essential, as disease-specific therapies are becoming available.