BACKGROUND AND AIMS: Hepatocellular adenomas (HCAs) in males are very rare. We performed detailed clinicopathologic, immunohistochemical and molecular characterization of HCAs in males, to understand their pathogenesis and malignant potential. METHODS: Seven cases of HCA in males formed our study cohort. The histologic slides, clinical and follow-up information were reviewed and immunohistochemical stains were performed. DNA was extracted and targeted sequencing was performed using Ion Torrent chemistry. Filtered variants were annotated to identify pathogenic mutations. RESULTS: Six (86 %) patients were morbidly obese. All showed at least focal cytologic atypia. Three lesions were markedly steatotic and 2 were hemorrhagic. One lesion showed focal reticulin loss, diffuse glutamine synthetase (GS) positivity and beta-catenin (β-catenin) nuclear staining, suggestive of atypical hepatocellular neoplasm. Three (42.8 %) cases were inflammatory-type, showing diffuse serum amyloid-associated protein/C-reactive protein. One other inflammatory-type HCA showed peripheral accentuation with GS and another non-inflammatory HCA showed patchy staining with GS
both revealed CTNBB1 mutations but no β-catenin nuclear staining. None showed TP53, TERT promotor mutations, or significant copy number alterations. CONCLUSION: A significant proportion of HCAs in males occurred in obese patients and were inflammatory-type. While some are beta-catenin mutated and need to be resected, a subset of HCAs in males appears to be low-risk by molecular features and may be treated conservatively.