PINEAL PARENCHYMAL TUMORS - CT AND MR FEATURES

Objective: Our goal was to characterize the CT, MR, and pathologic fea tures of pineal parenchymal tumors (PPTs). Materials and Methods: We r etrospectively reviewed 19 cases of resected PPTs with pathologic conf irmation [10 pineocytomas (PCs), 1 mixed pineocytoma-pineoblastoma (PC -PB), and 8 pineoblastomas (PBs)], noting clinical, CT, and MRI featur es. Results: 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 cyst ic. The mixed PC-PB was round and homogeneous. Eight precontrast CT sc ans of PCs and the PC-PB demonstrated calcifications, either periphera l (four of eight) or central (four of eight, including the mixed tumor ). Pineocytomas were hypodense (five of seven) tumors, with heterogene ous 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 hom ogeneously. Pineocytomas and the PC-PB had variable signal intensity o n MRI. Most PBs were hypo- to isointense on T1-weighted images, and si x of six enhanced heterogeneously postgadolinium. Conclusion: Pineocyt omas are predominantly smaller, round, hypodense, homogeneous masses w ith calcifications, particularly peripheral. They enhance heterogeneou sly on CT and present with a lesser degree of hydrocephalus in older p atients. Pineoblastomas, on the other hand, are larger, lobulated, hom ogeneous tumors, are infrequently calcified, and present with a greate r degree of hydrocephalus, often in young females. They tend to be hyp erdense on CT and hypo- to isointense on T1-weighted images and enhanc e homogeneously on CT and heterogeneously on MRI.