Occipital transtentorial approach and combined treatments for pineal parenchymal tumors.

The deep-seated location of pineal parenchymal tumors (PPTs) and their associations with critical structures make their surgical resection technically challenging; further, the rarity of PPTs and repeated changes in their histopathological diagnostic criteria makes the study of their biological behavior and clinical outcomes difficult. Here, we describe the surgical techniques and results of an occipital transtentorial approach for PPTs together with the results in the clinicopathological study of PPTs. Since 1982, we have treated 93 patients with pineal region tumors, including 17 PPTs, with the occipital transtentorial approach using the lateral semiprone position. The infrasplenial approach is helpful in separating the internal cerebral veins from the tumor, particularly when the tumor is tightly adherent to the veins. Permanent homonymous hemianopsia occurred in 1 of the 17 patients with PPTs. Permanent ocular movement disorders were not encountered. Extensive removal of the tumor significantly prolongs survival at least in patients with pineocytomas and PPT of intermediate differentiation (PPTIMD). Despite extensive resection and adjuvant radiochemotherapy, the prognosis of the patients with pineoblastomas is extremely poor. Although the proliferative potentials of pineocytomas and PPTIMD were significantly lower than those of pineoblastomas, there was no such difference between pineocytomas and PPTIMD. Copyright (c) 2009 S. Karger AG, Basel.