Atypical Hepatocellular Neoplasm With Peliosis in Cirrhotic Liver Versus Hepatocellular Carcinoma: A Diagnostic Trap

Abstract

Atypical hepatocellular neoplasm (AHN) is an adenoma-like hepatic tumor that even occurs in noncirrhotic liver of males (any age) or females ≥ 50 years old, or associates focal atypical features. In this article, 2 unusual cases diagnosed in elderly cirrhotic patients, unrelated to steroids, are presented. The first case was incidentally diagnosed in an 83-year-old female. During laparoscopic surgery for cholecystectomy, hemoperitoneum was installed and laparotomy was necessary to remove a 70-mm nodular encapsulated hepatic tumor that was microscopically composed by hepatocyte-like cells with clear cytoplasm, arranged in 1- to 2-cell-thick plates and intermingled with areas of peliosis, negative for alpha fetoprotein (αFP), p53, and keratin 7, with low Ki67 index and intact reticulin framework. The second case was incidentally diagnosed at ultrasound examination in a 66-year-old male. The surgical specimen was a 50-mm solid multinodular tumor that microscopically consisted of 3-cell-thick plates of hepatocyte-like cells with acinar, pseudoglandular, and trabecular architecture, intermingled with peliotic areas, without nuclear atypia and disintegrated reticulin framework. Both of the cases occurred in cirrhotic liver. The tumor cells were marked by AE1/AE3 keratin, displayed a Ki67 index < 5% and were negative for αFP, p53, and keratin 7. No recurrences or any other disorder occurred 6 months after surgery. In cirrhotic liver, adenomas with peliosis that do not satisfy all the diagnosis criteria synthesized in the article should be considered AHNs and differential diagnosis includes hepatocellular carcinoma but also focal nodular hyperplasia, regenerative nodules, and dysplastic nodules. This histological entity is not yet included in the WHO Classification list.

FIGURE 1

Gross findings of hepatic tumors from authors’ collection. (A and B) Atypical hepatocellular neoplasm—case 1; (C) encapsulated hepatocellular carcinoma—case 2; (D) multifocal hepatocellular carcinoma; (E) cholangiocarcinoma.

FIGURE 2

Microscopic features of the hepatic tumors of the cirrhotic liver. In case 1 (A–D), an atypical hepatocellular neoplasm diagnosed in an 83-year-old female, the tumor was covered by a connective capsule (A) and the proliferating cells with clear cytoplasm (A) were intermingled with large blood-filled spaces surrounded by hepatocytes, without lining endothelial cells (B and C); the reticulin (RET) framework is intact (D). In case 2 (E–H), an well-differentiated hepatocellular carcinoma diagnosed in a 66-year-old male, the proliferating cells show trabecular (E) and acinar architecture with clear cytoplasm (F), with large peliotic areas (G), and disintegrated RET framework (H).

FIGURE 3

Microscopic and immunohistochemical features of primary hepatic tumors that should be differentiated from hepatic adenomas and adenoma-like tumors.

FIGURE 4

Microscopic and immunohistochemical features of nontumor lesions of the liver that should be differentiated from hepatic adenomas and adenoma-like tumors.