Introduction: Optimal grading and treatment of pineal parenchymal tumor of intermediate differentiation (PPTID) have not been established due to its rarity.

Methods: After careful review of more than 500 pineal region tumors treated in our center, 27 patients with PPTID were identified (Figure 1). Diagnoses were confirmed according to WHO classification and graded as suggested by Jouvet et al[1]. Relationship between WHO grade, histopathological characters, management and outcome were analyzed.

Results: WHO grade didn’t demonstrate significant correlation with outcome. Mitotic count and Ki-67 labeling index (LI) were detected as prognostic factors. Stratification of patients by mitotic count and Ki-67 LI correlate significantly with overall survival and progression free survival. All the patients underwent resection. GTR was achieved in 16/27 (59.3%) patients, STR in 6/27 (22.2%) patients, and PR in 5/27 (18.5%) patients (Figure 2e and f). Log rank test confirmed GTR correlated significantly with better survival. Adjuvant therapy has a tendency to correlate significantly with progression free survival. Among the high risk patients, 6/9 patients with residual tumor received radiotherapy and 50% (3/6) were free of local tumor recurrence. In the other 3 high-risk patients with residual tumor who didn’t receive adjuvant therapy, recurrence occurred at an early time.

Conclusions: Risk evaluation combining mitotic count and Ki-67 labeling index predict prognosis (Figure 2a-2d). Surgery is the most efficient management. GTR is related with better prognosis. If GTR is not achieved, adjuvant therapy might delay tumor progression or recurrence, especially in high risk patients.

Patient Care: Optimal grading and treatment of pineal parenchymal tumor of intermediate differentiation (PPTID) have not been established due to its rarity. Our study found out that risk evaluation combining mitotic count and Ki-67 labeling index predict prognosis (Figure 2a-2d). Surgery is the most efficient management. GTR is related with better prognosis. If GTR is not achieved, adjuvant therapy might delay tumor progression or recurrence, especially in high risk patients.

Learning Objectives: Risk evaluation based on histopathological parameters of Pinea prenchymal tumor of intermediate differentiation. Management of pinea prenchymal tumor of intermediate differentiation based on risk evaluation.

References: 1. Jouvet, A., et al., Pineal parenchymal tumors: a correlation of histological features with prognosis in 66 cases. Brain Pathol, 2000. 10(1): p. 49-60.