August 2022 – Liver Pathology

A 39-year-old male patient with abdominal pain underwent a CT scan and was found to have a hepatic lesion, which on resection had an appearance demonstrated on H/E (Figure 1) and reticulin stain (Figure 2). It was further interrogated with immunostains shown below. 

Figure 1: H/E
Figure 2: Reticulin stain
Figure 3: β-catenin
Figure 4: CRP
Figure 5: HAA
Figure 6: LFABP

Which one of the following is the correct choice?

  • β-catenin activated hepatic adenoma
  • Inflammatory hepatic adenoma
  • HNF1A inactivated hepatic adenoma
  • Hepatic adenoma, unclassified type

The correct answer is ...

Hepatic adenoma, unclassified type.

As seen on H/E (Figure 1), there is some expansion of hepatic plate and focal acini formation but with a lack of cytologic atypia, uniformly condensed nuclei, and low N/C ratio, lack of prominent nucleoli, and preserved reticulin stain (Figure 2), supporting the diagnosis of hepatic adenoma. Immunostains obtained to classify the hepatic adenoma further show a normal membranous expression of β-catenin (Figure 3), which rules out β-catenin activated hepatic adenoma, which will show an abnormal nuclear expression of β-catenin. Expression of C-reactive protein (CRP) (Figure 4) is similar to the background liver, and hepatic amyloid A (Figure 5) expression is absent, which rules out inflammatory type hepatic adenoma. Liver-type fatty acid-binding protein (LFABP) expression (Figure 6) is preserved, which rules out the HNF1A inactivated hepatic adenoma. Hence the correct answer is a hepatic adenoma, unclassified type. 


  1. Balitzer D, Kakar S. Diagnostic challenges and risk stratification of hepatocellular adenoma. Diagn Histopathol. 2022;28(2):89-102.
  2. Torbenson MS. Diagnostic approach to well-differentiated hepatocellular carcinoma. Diagn Histopathol. 2022;28(2):69-78.
  3. Dhingra S, Fiel MI. Update on the new classification of hepatic adenomas: clinical, molecular, and pathologic characteristics. Arch Pathol Lab Med. 2014 Aug;138(8):1090-7. doi:10.5858/arpa.2013-0183-RA. PMID: 25076298
Square photo of Ameya Patil

Ameya Patil, M.B.B.S.

Resident, Anatomic and Clinical Pathology
Mayo Clinic

Lizhi Zhang, M.D.

Consultant, Anatomic Pathology
Mayo Clinic
Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science

MCL Education

This post was developed by our Education and Technical Publications Team.