Intrahepatic cholangiocarcinoma resembling a thyroid follicular neoplasm.

The first case of well-differentiated intrahepatic cholangiocarcinoma with remarkable follicular architecture resembling a follicular neoplasm of thyroid is described in a 52-year-old man. The follicles contained homogenous eosinophilic material akin to colloid and were lined by benign-looking cuboidal cells. Immunohistochemically, thyroid transcription factor-1 (TTF-1) and thyroglobulin were negative and the patient had no evidence of a previous or concomitant thyroid tumour. This case can be added to the list of extrathyroid primary tumours that resemble thyroid neoplasms.