We identified 53 patients with non-neoplastic cysts of the pineal gland. In contrast to patients with pineal neoplasms, pineal cysts are usually asymptomatic. They infrequently obstruct the aqueduct to cause hydrocephalus or compress the tectum to produce the neuro-ophthalmologic signs of dorsal midbrain dysfunction. Obstructive hydrocephalus was present in only five patients (9.4%); three of them showed clinical signs of Parinaud's syndrome. CT and MRI typically reveal a cystic mass that averages 1.6 cm in anteroposterior (A-P) diameter with calcification at the periphery and faint rim-like contrast enhancement. Sagittal MRI is the most useful diagnostic test because it shows the anatomic relationship of the cyst to the aqueduct. The mass may compress the tectum and distort the proximal aqueduct; occasionally a large cyst may occlude the aqueduct. All patients with obstructive hydrocephalus had cysts greater than 2.0 cm in A-P diameter. Nine patients had suboccipital craniotomy. In all of them, the cysts contained clear fluid and were easily removed. We advocate conservative management with clinical observation of these benign lesions that may be developmental variants of normal pineal gland.

The computed tomographic (CT) features of pineal region tumors were analyzed in 60 histologically proven tumors. This is the largest reported series of histologically verified pineal region tumors studied with CT. The tumors were classified as germ-cell tumors, glial tumors, pineal parenchymal tumors, and meningiomas. Preenhancement germinomas revealed characteristically high-density areas with calcification; uniform enhancement was seen after injection of contrast material. When present, pineal calcification was engulfed by the tumor. Teratomas, present only in male patients, revealed areas of mixed densities (e.g., calcification and fatty areas) and did not show significant contrast enhancement. Spontaneous intraventricular rupture was noted in one case. Unlike other tumors, the original pineal calcification could be recognized in two-thirds of glioma cases and was displaced anteriorly and superiorly in most. Gliomas were hypodense to isodense on precontrast scans and enhanced in a nodular and a ring fashion. Benign pineal parenchymal tumors showed iso- to hyperdense areas with nodular enhancement after injection of contrast material. Pineoblastomas were well defined hyperdense masses without calcification on precontrast scans. After injection of contrast material, they showed well defined enhancement with occasional small, central lucencies. Meningiomas were hyperdense in most cases, uniformly enhanced in a homogeneous fashion, and showed a tentorial attachment.