Pineoblastoma
Abstract
Young male with headache and vomiting
Keywords
Pineoblastoma, pineal region, MRI, MRS, CT, shunt, 653, spectroscopy, brain tumor
Publication Date: 205-06-01
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History
Young male with headache and vomiting
Findings
MRI: There is a round, homogeneous pineal region mass demonstrating intermediate T2 and high FLAIR signal intensities. It enhances diffusely with gadolinium. It exerts mass effect upon the tectum, which compresses the cerebral aqueduct causing obstructive hydrocephalus.
MRS: There is elevation of choline, decrease of NAA, and a lactate peak, compatible with high grade tumor.
Noncontrast CT, status-post shunting: There is a round, hyperdense, pineal region mass, containing calficications.
Diagnosis
Pineoblastoma
Differential
Germinoma, pineocytoma, pineoblastoma
Discussion
Pineoblastomas and pineocytomas are tumors of pineal cell origin. Pineoblastomas generally occur in a younger age group, peaking in the first decade of life whereas pineocytomas peak in the second decade. Like other pineal region masses, they can present with hydrocephalus due to obstruction of the cerebral aqueduct. There is equal incidence of pineoblastomas and pineocytomas in males and females. Germinomas, however, show a distinct male predominance. They can present with precocious puberty owing to the hormones they secrete.
On imaging alone, pineoblastomas can be difficult to distinguish from other tumors in the differential. Being composed of cells with a high nuclear:cytoplasm ratio, they, like germinomas and pineocytomas, appear dense on noncontrast CT and isointense to slightly hypointense on T2 MR. They do not contain calcifications or cystic areas as commonly as pineocytomas and both enhance moderately with gadolinium. The size of the lesion may be a clue to its diagnosis, as it is commonly larger than a pineocytoma, which are usually less than 3cm in size. Pineoblastomas are also more aggressive (WHO grade IV) and, as such, have a higher incidence of subarachnoid seeding than pineocytomas (WHO grade II), and a worse prognosis.
References
- Grossman, R. I. and Yousem, D. M. Neuroradiology: The Requisites, 2004.