Pineal Parenchymal Tumors of Intermediate Differentiation: A long-Term Follow-Up Study in Helsinki Neurosurgery.

Background: Pineal parenchymal tumors of intermediate differentiation (PPTIDs) are rare lesions with particular features compared with other pineal parenchymal tumors.

Methods: We present a retrospective review of patients with histologically confirmed PPTIDs who were operated on in our department between 1997 and 2015. A demographic analysis and an evaluation of preoperative status, surgical treatment, as well as immediate and long-term clinical and radiologic outcomes were conducted.

Results: Fifteen patients with PPTIDs were operated on between 1997 and 2015. Gross total removal was achieved in 11 cases; 2 patients underwent near-total resection, 1 partial resection, and 1 received brachytherapy after an endoscopic biopsy. Nine patients required external radiation therapy (4 due to a pleomorphic histology of their lesion including pineoblastoma features in 3 of them; 3 after a subtotal resection; and 2 for tumor recurrence). No patient received chemotherapy. The survival rate of our patients was 57.1% at a mean follow-up of 137.2 ± 77.6 months (39-248 months).

Conclusions: A proper multidisciplinary management of PPTIDs based on a gross total removal of the lesion, and an adjuvant radiotherapy in selected cases, may improve the overall survival of these aggressive tumors.