Cervical teratoma in a fetus and an adult. Two case reports and review of literature.

Two cases of cervical teratoma in a 30-weeks fetus and a 26-year-old female have been presented. In the former case a large mass entirely occupied the anterior neck but showed no invasive or metastatic lesions, and in the other case a mass containing multiple cysts was situated in the right lower pole of the thyroid gland. Histologically, both tumors were composed of the elements derived from three germ layers including various epithelial components, cartilage, muscle, and adipose tissue. In addition to these predominantly mature elements, there were some elements showing primitive immature structure in the former case. Positive immunohistochemical staining for thyroglobulin displayed only in the former case and was observed in the compressed thyroid follicles located in the fibrous capsule and several small foci of primitive glandular structure which was an element of the tumor.