Surgicopathological classification of hepatic space-occupying lesions: a single-center experience with literature review

Abstract

Accompanying rapid developments in hepatic surgery, the number of surgeries and identifications of histological types of primary hepatic space-occupying lesions (PHSOLs) have increased dramatically. This has led to many changes in the surgicopathological spectrum of PHSOLs, and has contributed to a theoretical basis for modern hepatic surgery and oncological pathology. Between 1982 and 2009 at the Eastern Hepatobiliary Surgery Hospital (EHBH) in Shanghai, 31 901 patients underwent surgery and were diagnosed as having a PHSOL. In this paper, we present an analysis of the PHSOL cases at the EHBH for this time period, along with results from a systematic literature review. We describe a surgicopathological spectrum comprising more than 100 types of PHSOLs that can be stratified into three types: tumor-like, benign, and malignant. We also stratified the PHSOLs into six subtypes derived from hepatocytes; cholangiocytes; vascular, lymphoid and hemopoietic tissues; muscular, fibrous and adipose tissues; neural and neuroendocrine tissues; and miscellaneous tissues. The present study provides a new classification system that can be used as a current reference for clinicians and pathologists to make correct diagnoses and differential diagnoses among various PHSOLs.

Keywords: Classification; Immunohistochemistry; Liver tumors; Pathology; Tumor-like lesions.

Figure 1

Atypical focal nodular hyperplasia with minimal fibrous septa (A, HE stain, × 200) shows focal microvessels around the periphery of the fibrous septa (B, CD34 immunostaining, × 200). Hepatocellular adenoma is composed of benign-looking hepatocytes with mild steatosis, without a capsule around the periphery (C, HE stain, × 200), and shows a chaotic microvessel distribution pattern with thin-walled vascular staining (D, CD34 immunostaining, × 200). Highly differentiated hepatocellular carcinoma is arranged in a thin trabecular pattern (E, HE stain, × 400) and shows a sinusoidal capillarization pattern (F, CD34 immunostaining, × 200).

Figure 2

Infiltration of neoplastic cells of hepatic angiomyolipoma within the hepatic sinusoid (A, HE stain, × 200) with strong HMB45 positive staining (B, immunostaining, × 200), and within a branch of the portal vein (C, HE stain, × 100) with strong HMB45 positive staining (D, immunostaining, × 200).