CN-12 * PINEAL PARENCHYMAL TUMOUR OF INTERMEDIATE DIFFERENTIATION: CASE SERIES FROM A SINGLE INSTITUTE

Abstract

INTRODUCTION: Pineal parenchymal tumours of intermediate differentiation (PPTID) are a group of rare tumours with intermediate malignant potential between pineocytoma and pineoblastoma, for which there is currently no standard treatment paradigm. METHODS: Between 2001 and 2014, five patients with PPTID were treated at our institute. We retrospectively evaluated clinical outcomes. Patient demographics, presentation, staging, surgery, radiotherapy (RT) technique, late toxicities and any chemotherapy administered were noted from the hospital electronic data base. RESULTS: Patient age range 20-74 years. Common presenting symptom was headache and visual disturbance and neurological sign was diplopia. All had ventriculostomy plus or minus ventriculo-peritoneal shunt to relieve hydrocephalus. Two patients had biopsy only and three patients had excision of pineal tumour. Three patients underwent whole brain RT with boost to pineal region [35.07Gy in 21 fractions - whole brain, average boost dose- 17.81Gy (16.7- 20.04 Gy) at 1.67Gy/fraction]. Two patients had limited field RT to the pineal region (54Gy and 39.6 Gy delivered in 1.8 Gy/fraction). Four patients had complete radiological response on MRI post-RT. One patient had partial radiological response. Two patients recurred after an average disease free survival period of 54.5 months from diagnosis: one recurred locally and was retreated with radiosurgery; the other developed disseminated leptomeningeal disease and received platinum based palliative chemotherapy. Four patients are alive to date. Average overall survival including relapsed patients is 102.5 months. Median DFS and OS are 41 and 100 months respectively. All patients developed mild cognitive impairment. The patient who received platinum chemotherapy developed severe neuropathy. CONCLUSION: Patients with PPTID in this case series survived medium term and four remain on follow up. A prospective multi institutional study is recommended due to the potential for late adverse effects. However, because this entity is rare, the difficulties in achieving this are recognised therefore cases should be collated at centres for review.