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Neuroradiology Case of the Week

Case 123

Loris F. Cedeno, MD and Per-Lennart Westesson, MD, PhD, DDS

Clinical Presentation: A 66-year-old male presented with severe headache and left-sided neck stiffness but no neurological symptoms.

Radiological Findings: Contrast CT of the brain demonstrates a well defined ova-shaped mass in the pineal region. Inferiorly, this mass appears to obstruct the aqueduct of Sylvius with resultant hydrocephalus of the third and lateral ventricles (Figs. 1& 2).
     MR images of this region demonstrate a well defined oval mass measuring 1.7 x 1.5 x 1.6 cm in anterior-posterior, lateral and craniocaudal dimensions respectively. It is located in the posterior wall of the third ventricle and pineal region. This mass is isointense to slightly hyperintense on T1WI and shows heterogeneous moderate enhancement after contrast administration. In the sagittal images, it is seen obstructing the aqueduct of Sylvius. There is associated dilatation of the third and lateral ventricles without associated interstitial edema. On T2WI, it is isointense to the adjacent brain parenchyma and demonstrates tiny cysts within it (Figs. 3-6).

Discussion: Pineal region tumors constitute only 0.3% - 2.7% of intracranial tumors. Papillary tumors of the pineal gland are extremely rare with less than ten case reports in the literature. In this region, diagnostic possibilities for this patient included glioma, ependymoma, metastasis and pineal tumors such as pineoblastoma and pineocytoma. Germinoma was less likely due to the patient’s age.
     Pathologically, this tumor demonstrates papillary features and pseudo-rosettes. The cell of origin of this tumor shares morphologic features with both papillary ependymoma and choroid plexus papilloma and is believed to be a modified ependymal cell of the subcommissural organ.

References:

1. Jouvet A, Fauchon F, Liberski P, Saint-Pierre G, Didier-Bazes M, Heitzmann A, Delisle MB, Biassette HA, Vincent S, Mikol J, Streichenberger N, Ahboucha S, Brisson C, Belin MF, Fevre-Montange M. Papillary tumor of the pineal region. Am J Surg Pathol 2003 Apr;2(4)7:505-512. [Medline]
2. Kroppenstedt SN, Golfinos J, Sonntag VK, Spetzler RF. Pineal region lesion masquerading choroid plexus papilloma: case report. Surg Neurol 2003 Feb;59(2):124-127; discussion 127. [Medline]
3. Shibahara J, Todo T, Morita A, Mori H, Aoki S, Fukayama M. Papillary neuroepithelial tumor of the pineal region. A case report. Acta Neuropathol (Berl). 2004 Oct;108(4):337-340. [Medline]