Symptomatic cysts of the pineal gland: stereotactic diagnosis and treatment of two cases and review of the literature.

We report two cases of pineal gland cysts, both in young girls, causing aqueductal stenosis and symptomatic hydrocephalus, which were diagnosed and treated by Talairach's stereotactic method. This procedure permitted aspiration of the cyst content, normalization of aqueductal stenosis, and a differential histological diagnosis. Postoperative computed tomographic scan examination showed a stable reduction of the cystic volume and a complete clearance of the hydrocephalus. At present, the two patients are clinically normal and are leading a productive life (follow-up, 42 and 40 mo). It is important that this kind of nonneoplastic lesion be identified, in order to avoid confusion with pineal tumors and possible inappropriate treatment. Pineal cysts rarely become symptomatic. Up to the present, only 27 symptomatic cases have been described in the literature. Of those, signs of intracystic bleeding were found in 17 of the 21 cases in which the cyst contents were known. Moreover, in our own two cases, numerous hemosiderin-laden macrophages were present in the cystic fluid. We think, therefore, that intracystic bleeding has been the determining factor for the occurrence of symptoms in most of these cases. The authors underline the advantages of this type of stereotactic management, which can provide both diagnosis and treatment and thus avoid the possible risks of surgical excision and/or of radiotherapy.