Clinicopathological study of pineal parenchymal tumors: correlation between histopathological features, proliferative potential, and prognosis.

This study describes the clinicopathologic features of 13 cases with pineal parenchymal tumors. Based on the histopathologic findings, especially the extent of atypia and pineocytic differentiation as determined by Bodian's staining, we classified these tumors into pineocytomas (4), pineocytomas with anaplasia (4) and pineoblastomas (5). All the cases with pineocytoma and pineocytoma with anaplasia were adults, and all the cases with pineoblastoma were younger children. One patient with pineocytoma died of other disease 7 months after initial treatment. One patient with pineocytoma with anaplasia died 168 months after initial treatment. The other patients with pineocytoma and pineocytoma with anaplasia survived between 9 and 179 months after surgery. However, all of the five pineoblastoma patients died within 14 months after initial treatment. The mean MIB-1 index in pineoblastomas was significantly higher than that in other types of pineal parenchymal tumors, but there were no differences between pineocytomas and pineocytomas with anaplasia with respect to the MIB-1 index. The mean MIB-1 index in neurofilament protein-immunopositive cases was significantly lower than that in immunonegative cases. With regard to the malignant potential, we emphasize that a clear distinction should be made between pineoblastomas in children and other types of pineal parenchymal tumors in adults.