Mature cystic teratomas of the ovary with intestinal wall structures harboring intestinal- type epithelial neoplasms.

Mature cystic teratomas of the ovary frequently contain intestinal-type tissues, but these rarely organize into complete intestinal walls, including all layers, and even more rarely develop secondary neoplasms. The present report documents two mature teratomas with formation of complete segments of intestinal wall, one also containing a benign mucinous cystadenoma of the appendiceal type and the other an intestinal-type adenocarcinoma infiltrating into the neoplastic bowel wall but not the surrounding ovarian parenchyma. The latter patient is alive and well 5 years after surgery. These cases expand the repertoire of secondary neoplasms, benign and malignant, developing in mature cystic teratomas.