Fractionated Gamma Knife Radiation for Papillary Tumor of the Pineal Region: A Case Report and Literature Review.

Papillary tumor of the pineal region (PTPR) is a rare central nervous system neoplasm with an unpredictable clinical course. Gross total resection, the preferred treatment, is often unachievable due to the tumor's deep-seated location, necessitating alternative therapies. We report the case of a 24-year-old male with recurrent grade 3 PTPR. Initial subtotal resection followed by adjuvant volumetric modulated arc therapy (50.4 Gy in 28 fractions) failed to control tumor progression. After a second subtotal resection for recurrence, the patient underwent fractionated stereotactic radiotherapy (fSRT) using Gamma Knife Icon, delivering a total dose of 28 Gy in eight fractions. One year post-fSRT, significant tumor shrinkage was observed, and the patient maintained clinical stability. This case highlights fSRT's potential as an effective salvage treatment for recurrent PTPR, particularly in anatomically challenging regions where gross total resection is not feasible. To our knowledge, this is the first report detailing the successful use of fractionated Gamma Knife radiosurgery for a large, recurrent primary PTPR refractory to previous multimodal treatment, suggesting a valuable therapeutic option for this challenging condition.