Pineal parenchymal tumors: CT and MR features

Our goal was to characterize the CT, MR, and pathologic features of pineal parenchymal tumors (PPTs).

We retrospectively reviewed 19 cases of resected PPTs with pathologic confirmation [10 pineocytomas (PCs), 1 mixed pineocytoma-pineoblastoma (PC-PB), and 8 pineoblastomas (PBs)], noting clinical, CT, and MRI features.

Six male and four female patients presented with PC, one female patient with mixed PC-PB, and seven female and one male patient with PB. The CT imaging revealed 6 of 10 round and 6 of 10 small- to medium-sized masses; 7 of 9 were homogeneous, 1 of which appeared cystic. The mixed PC-PB was round and homogeneous. Eight precontrast CT scans of PCs and the PC-PB demonstrated calcifications, either peripheral (four of eight) or central (four of eight, including the mixed tumor). Pineocytomas were hypodense (five of seven) tumors, with heterogeneous postcontrast enhancement (five of seven). Most PBs (six of eight) were lobulated, and five of eight were homogeneous. Four of eight PBs imaged with CT were noncalcified hyperdense masses, which enhanced homogeneously. Pineocytomas and the PC-PB had variable signal intensity on MRI. Most PBs were hypo- to isointense on T1-weighted images, and six of six enhanced heterogeneously postgadolinium.

Pineocytomas are predominantly smaller, round, hypodense, homogeneous masses with calcifications, particularly peripheral. They enhance heterogeneously on CT and present with a lesser degree of hydrocephalus in older patients. Pineoblastomas, on the other hand, are larger, lobulated, homogeneous tumors, are infrequently calcified, and present with a greater degree of hydrocephalus, often in young females. They tend to be hyperdense on CT and hypo- to isointense on T1-weighted images and enhance homogeneously on CT and heterogeneously on MRI.