Chapter 13 Hepatic Tumors, Benign 1 Hepatocellular adenoma, telangiectatic type (inflammatory hepatocellular adenoma) Case 13.2

Clinical Presentation 13 Hepatic Tumors, Benign 2 Clinical Presentation A pleasant 44-year-old woman was noted during a routine physical exam to have a liver mass. She had a history of using oral contraceptives. MRI showed a liver lesion with signal characteristics not typical for hemangioma and suggestive of fibrolamellar hepatocellular carcinoma.

Laboratory Values Course in Hospital AST: 91 ALT: 60 Alk Phos: 193 13 Hepatic Tumors, Benign 3 Laboratory Values AST: 91 ALT: 60 Alk Phos: 193 Total Bilirubin: 0.6 Total Protein: 6.9 Albumin: 4.3 α-Fetoprotein: 0.8 Course in Hospital No core biopsy was performed and the tumor was resected.

13 Hepatic Tumors, Benign 4 Pathology The tumor measured 8 × 7 × 4.2 cm and was variegated tan-brown and nodular. Microscopically the tumor was composed of cytologically benign hepatocytes forming normal sized hepatic cords with variable and often prominent sinusoidal dilatation (a, b). Figure 13.2(a) Figure 13.2(b)

13 Hepatic Tumors, Benign 5 Pathology Scattered within the tumor were portal-like structures with no interlobular bile ducts; however, peripherally located ductules were present (c), confirmed on the positive CK7 immunoperoxidase stain (d). There was no evidence of hepatocellular carcinoma. Figure 13.2(c) Figure 13.2(d)

13 Hepatic Tumors, Benign 6 Diagnosis Hepatocellular adenoma, telangiectatic type (inflammatory hepatocellular adenoma, IHCA)

13 Hepatic Tumors, Benign 7 Comment This variant of hepatocellular adenoma is associated with focally dilated sinusoids and small portal-like structures with adjacent ductules. The differential diagnosis often includes focal nodular hyperplasia which also has fibrosis and ductules. Additionally fibrolamellar hepatocellular carcinoma which oftentimes has a central scar is also often considered in the differential diagnosis based on imaging (as in this case example), where biopsy clearly distinguishes between the two.

13 Hepatic Tumors, Benign 8 Comment Table 13.3 (Hepatocellular adenoma versus focal nodular hyperplasia) in Chapter 13 shows the similarities and differences between the two benign hepatic tumors, both by routine and immuno-histochemical staining. Although the ductules in this case example are obvious on the routine H&E stain, confirmation with CK7 immunoperoxidase stain can be helpful for confirmation.