The teratoma is common among children; it has a male predominance. Unlike the germinoma, on MR images a teratoma appears inhomogenous due to the presence of cysts and hemorrhages.

The tumor is composed of an admixture of tissues derived from all three germinal layers of the embryonic disc: ectoderm, mesoderm, and endoderm. Some terato-mas are composed of well-differentiated, mature tissue resembling benign adult organs (mature variant) and others of immature tissue resembling fetal tissue (immature variant). Teratomas commonly are situated in the pineal region, less often in the suprasellar region, and rarely within the parenchyma. Grossly, they are cystic, often hemorrhagic, and contain calcifications. Histo-logically, they contain a mixture of epithelial, mesen-chymal, and glandular elements.

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