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.
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.
Ameya Patil, M.B.B.S.
Resident, Anatomic and Clinical Pathology
Lizhi Zhang, M.D.
Consultant, Anatomic Pathology
Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science