Specific Imaging Findings

The lesions arise from the pineal gland and are typically hyperdense on non-contrast CT with variable enhancement. Tumors often contain calcifications, particularly in their periphery (so-called “exploded” calcifications), which is the most specific imaging finding. On MRI, the solid portions show very low ADC values and tend to be T2 iso to hypointense. Cysts and hemorrhage are not uncommon. After contrast administration, enhancement is the rule. Hydrocephalus is frequently present. Screening of the entire craniospinal axis before surgery is needed to rule out CSF tumor spread. MR spectroscopy shows marked elevation of choline, low-to-absent NAA, lactate, lipids and occasionally a specific peak at 3.4 ppm on short echo time studies, thought to represent taurine. On perfusion studies these masses show high relative cerebral blood volume.

Pertinent Clinical Information

Pineoblastomas are generally found in children and young adults. Some series report a slightly increased incidence in females. Because of their location, compression of the aqueduct of Sylvius leads to early onset of hydrocephalus and compression of the brainstem. Symptoms include elevated intracranial pressure, headaches, nausea/vomiting, ataxia and Parinaud syndrome. Nearly a half of the patients, regardless of their age presentation, will be found to have CSF tumor spread and thus many treatment protocols assume that all patients have it and treat the entire craniospinal axis. The main modes of treatment are initial tumor resection/debulking followed by chemotherapy and in older patients a combined chemo-radiation protocol.