A hepatocellular neoplasm accompanied with massive histiocyte infiltration

Area of Science:

• Hepatobiliary pathology
• Oncology
• Immunology

Background:

• Hepatocellular adenomas (HCAs) are benign liver tumors.
• Malignant transformation of HCAs to hepatocellular carcinoma (HCC) is rare.
• Diabetes mellitus and obesity are risk factors for liver disease.

Purpose of the Study:

• To describe a unique case of hepatocellular nodule with features of malignant transformation.
• To investigate the role of macrophages in the tumor microenvironment.

Main Methods:

• Histopathological examination of the liver nodule.
• Immunohistochemical analysis for macrophage markers (monocyte chemoattractant protein-1, macrophage colony-stimulating factor).

Main Results:

• The unique nodule showed a combination of hepatocellular adenoma and hepatocellular carcinoma-like features.
• Abundant foam cell-type histiocytes (macrophages) were present within the tumor.
• Tumor cells expressed higher levels of monocyte chemoattractant protein-1 and macrophage colony-stimulating factor compared to background liver.
• Macrophages contained abundant fat droplets, suggesting phagocytosis of intercellular lipids.

Conclusions:

• This case represents a rare instance of hepatocellular adenoma with suspected malignant transformation.
• Macrophage infiltration, potentially induced by tumor cells, plays a significant role in the tumor's unique morphology, possibly through lipid phagocytosis.