Recurrent choroid plexus carcinoma treated with CyberKnife radiosurgery: illustrative case.

backgroundChoroid plexus carcinomas (CPCs) are rare malignant brain tumors primarily affecting children younger than 2 years old. These tumors originate from the choroid plexus epithelium and are a subtype of choroid plexus tumors, which account for 1%-4% of pediatric brain tumors. Although CPCs often show a notably high recurrence rate after surgery, the standard treatment approach remains gross-total resection (GTR) of the tumor, given the lack of clinical data supporting the effectiveness of adjunct treatment options such as radiotherapy or chemotherapy. OBSERVATIONS: A 16-year-old female with a history of a recurrent cranial CPC resistant to surgery and radiotherapy was treated with CyberKnife stereotactic radiosurgery (SRS), following resection. The procedures successfully maintained local disease control for 41 months; however, there was a subsequent recurrence, ultimately leading to the death of the patient. LESSONS: CPC treatment remains challenging. SRS can be used as a viable adjunct to surgery, which remains the gold standard, although it can also be considered for nonsurgical candidates or when GTR cannot be achieved. Nevertheless, it is crucial to conduct additional research to explore diverse approaches for radiosurgery, including its role as the primary treatment modality versus its combination with surgery, radiotherapy, or chemotherapy. https://thejns.org/doi/10.3171/CASE23748.