10050-RC-1 Site-Specific Treatment Response and Multidisciplinary Management of Cervical Spinal Metastasis from Pineal Parenchymal Tumor of Intermediate Differentiation: A Case Report

Abstract Background Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare central nervous system tumor, and spinal metastases are extremely uncommon. Because of its rarity and response variability based on location, there is currently no established standard treatment. Case A 45-year-old woman presented with impaired consciousness and was diagnosed with a pineal mass. Maximal tumor resection was performed via craniotomy, and histopathological analysis confirmed PPTID (WHO Grade3). Postoperative MRI revealed an asymptomatic mass at the C6 spinal level. Craniospinal irradiation (36 Gy in 20 fractions) and three cycles of carboplatin and etoposide (CARE therapy) resulted in complete remission of both intracranial and spinal lesions. Intervention and Outcome Two years later, recurrence was observed at the same cervical site. Despite partial resection, re-administration of CARE therapy, and CyberKnife stereotactic radiotherapy, the spinal lesion progressed. The patient developed paraplegia and respiratory failure and died approximately four years after initial diagnosis. Notably, the intracranial lesion remained well-controlled throughout. Discussion This case revealed a significant difference in how treatments work between intracranial and spinal lesions. Factors that might contribute include differences in drug penetration, cerebrospinal fluid flow, and tumor biology specific to each site, such as ATRX or H3K27M mutations. Spinal spread of PPTID seems linked to treatment resistance and poor prognosis, indicating a possible need for more aggressive local or intrathecal therapies. Conclusion This case highlights the importance of recognizing site-specific treatment behavior in PPTID metastasis. Multidisciplinary management is essential, and further case accumulation and international collaboration are needed to determine optimal treatment strategies for this rare tumor.