Pineal parenchymal tumor of intermediate differentiation: Treatment outcomes of five cases.

Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare disease, first classified by the World Health Organization in 2000. The number of available studies on the treatment of PPTID is currrently limited and the optimal management for this disease has not yet been determined. We retrospectively evaluated the treatment outcomes for PPTID at our institute and analyzed the roles of radiation therapy and chemotherapy for this disease. The clinical data on five patients diagnosed with PPTID since 2000 were retrospectively reviewed. Patients with cerebrospinal dissemination at diagnosis received biopsy-only surgery, craniospinal and whole-ventricular irradiation and chemotherapy. Patients with locally limited disease at diagnosis received local or whole-ventricular irradiation after surgery. The median relapse-free and overall survival were 72.9 and 94.1 months, respectively. Two of the five patients developed a relapse of cerebrospinal dissemination after treatment and succumbed to the disease. All the patients who received both craniospinal and whole-ventricular irradiation exhibited evidence of cerebral white matter abnormalities in magnetic resonance imaging and developed neurocognitive disorders after treatment. Although PPTID may be aggressive and has cerebrospinal fluid seeding potential, PPTID patients may survive long-term, even after recurrence. Considering the long survival time and the late adverse effects due to intensive treatment, the irradiation field and usage of chemotherapy after surgery require optimization.