Bile duct adenoma with oncocytic features

Area of Science:

• Hepatobiliary pathology
• Surgical pathology
• Oncologic research

Background:

• Bile duct adenomas are typically benign liver lesions.
• Oncocytic neoplasms in the liver are uncommon and often malignant.
• Distinguishing benign from malignant oncocytic tumors is crucial for patient management.

Purpose of the Study:

• To report a rare case of bile duct adenoma with oncocytic change.
• To detail the morphological and immunophenotypic characteristics of this specific lesion.
• To contribute to the understanding of rare liver neoplasms.

Main Methods:

• Surgical resection and histopathological examination of a liver nodule.
• Immunohistochemical staining for cytokeratin 7, Hep Par 1, and Ki67.
• Microscopic analysis of cellular morphology, gland formation, and mucin presence.

Main Results:

• A 61-year-old male presented with an incidental liver nodule during surgery for colorectal adenocarcinoma.
• Histopathology revealed a lesion with bland cells in tightly packed glands, consistent with bile duct adenoma.
• Immunophenotype (CK7+, Hep Par 1-, mucin+, Ki67 8%) and morphology indicated oncocytic change.
• The presence of mucin and normal bile ducts within the lesion were notable features.

Conclusions:

• The described lesion represents a rare case of bile duct adenoma with oncocytic change.
• This case expands the known spectrum of benign oncocytic liver neoplasms.
• The findings underscore the importance of comprehensive histopathological and immunophenotypic analysis for accurate diagnosis.