Hepatocellular adenoma: Where are we now?

Abstract

Hepatocellular adenoma (HCA) is a benign hepatocellular neoplasm, commonly occurs in young women with a history of oral contraceptive use. Complications including hemorrhage and malignant transformation necessitate the need for a thorough understanding of the underlying molecular signatures in this entity. Recent molecular studies have significantly expanded our knowledge of HCAs. The well-developed phenotype-genotype classification system improves clinical management through identifying “high risk” subtype of HCAs. In this article, we attempt to provide updated information on clinical, pathologic and molecular features of each subtype of HCAs.

Phospholipase A2 Group IIA Is Associated with Inflammatory Hepatocellular Adenoma

“…One possibility as to which signaling pathway is upregulated in PLA2G2A expression is the activation of Wnt/β-catenin signaling but it was not enhanced in current two I-HCA tissues by GSEA and Metascape analyses. I-HCA subtypes in which SAA1/SAA2 and CRP are commonly positive have been categorized and three β-catenin-mutated subsets have recently been defined [ 5 , 6 , 26 ]. The β-catenin mutant activities, which were defined as the different mutated positions and reflected the possibility of tumor progression, are high in more than 70% of HCC tissues.…”

“…Results of comprehensive molecular and immune–histological studies aided representative HCA subtype classification as follows: hepatocyte nuclear factor 1 homeobox A (HNF1A) inactivated (H-HCA), inflammatory HCA (I-HCA), β-catenin mutated (β-HCA or β-IHCA), and sonic hedgehog activated (sh-HCA) [ 1 , 3 , 4 , 5 , 6 ]. The majority of HCA subtypes are I-HCA (33%), with strong and diffuse expression of serum amyloid A (SAA) and C-reactive protein (CRP) observed in the tumors; however, some tumors with these positive reactions are difficult to clearly distinguish from HCC.…”

Inflammatory Hepatocellular Adenoma Mimicking Focal Nodular Hyperplasia That Grew during Pregnancy and Changed Its Appearance on Magnetic Resonance Imaging after Delivery

“…In women, for tumors with a persistent size of >5 cm or those that continue enlarging even after lifestyle changes, resection or curative treatment is indicated, irrespective of the subtype. For HNF1A-inactivated HCA subtype tumors measuring <5 cm or those that are inflammatory or negative for β-catenin on a biopsy, conservative management is recommended ( 20 ). Based on these management strategies, follow-up with periodic imaging studies, such as US and MRI, appeared reasonable for our patient.…”

PSMA Immunohistochemistry in Hepatic Neoplasms

“…8 For HCC cases, ancillary studies results including archived CK19 immunostains were reviewed with a cutoff of ≥ 5% of tumor staining as positive. 38 For HA cases, morphologic findings suggestive of inflammatory subtype (I-HA; ie, inflammatory infiltrate, dilated sinusoids, pseudoportal tracts with ductular reaction) were recorded 39 and ancillary tests including betacatenin immunostain were reviewed when available. In all cases, background liver was assessed for the presence of fatty liver disease and degree of fibrosis.…”