Abstract

Background: Intrahepatic cholangiocarcinoma (ICC) is arising from the intrahepatic bile ducts and accounts for 8%-10% of all malignant hepatic tumors.
Case Presentation: We report the case of a 42-year-old woman having ICC with thyroid-like follicular pattern. The patient had 9-cm solitary liver mass showing morphological pattern resembling thyroid follicles. Immunohistochemistry was negative for thyroid markers. The patient had no evidence of a previous or concomitant thyroid tumor. This case can be added to the list of extrathyroidal primary tumor that morphologically resembles thyroid neoplasms. Only three such cases have been previously reported in the literature. Such a pattern is known to occur in primary kidney and breast tumor. Thyroid like pattern broadens the morphological spectrum of cholangiocarcinoma.
Conclusion: Careful evaluation of this morphological rare variant of ICC is very essential to prevent misdiagnosis of metastatic thyroid follicular neoplasm.

Key words: Cholangiocarcinoma, thyroid follicle-like pattern, thyroid transcription factor 1 (TTF-1).