Multicentric juvenile pilocytic astrocytoma occurring primarily in the trigone of the lateral ventricle.

The authors report a juvenile pilocytic astrocytoma (JPA) in the trigone of an 11-year-old girl, apparently with disseminated lesions that disappeared spontaneously after the removal of primary lesion. Gadolinium-enhanced magnetic resonance images (MRIs) showed features suggestive of the development of multicentric spread of the tumor at the initial diagnosis. Histologically the primary tumor showed the typical features of a JPA. Serial postoperative MRIs demonstrated that everything except a remnant of the primary tumor seemed to regress spontaneously without any adjuvant therapy. The site of origin of this tumor is thought to be the subependymal glia of the occipital lobe.