Mature cystic teratoma arising at the porta hepatis: a diagnostic dilemma.

Mature cystic teratoma (MCT) is a tumor of embryological origin, which contains tissue derived from any or all germ cell lines found in an abnormal location. We present 2 cases of MCT both arising from the porta hepatis that were incorrectly thought perioperatively to be a choledochal cyst, which subsequently were demonstrated on histology to be a MCT.