Symptomatic Meckel's Cave Metastasis from Castration-resistant Prostate Cancer Treated with Gamma Knife Radiosurgery

Prostate cancer commonly spreads to the axial and appendicular skeleton, but metastases to the brain parenchyma or skull base are uncommon. In the cases that this happens, the symptoms are usually associated with disease involving the orbit. Metastasis to the Meckel's cave causing trigeminal nerve palsy is an exceedingly rare entity. We are presenting a case of this in a man with metastatic castration-resistant prostate cancer. Metastatic prostate cancer to the Meckel's cave is extremely uncommon, and there is no standard of care. Radiation therapy, especially radiosurgery, is increasingly recognized as an excellent alternative to surgery for lesions in the Meckel's cave and intracranial/skull base prostate cancer metastases. Gamma Knife radiosurgery (Elekta, Stockholm, Sweden), in particular, has been reported to achieve local control close to 90% for calvarial and skull base metastases with few side effects and requires only one treatment. Our patient's 1.4 x 1.0 x 1.3 cm metastatic prostate cancer lesion in the Meckel's cave was treated with Gamma Knife to 22 Gy with good treatment response including rapid improvement in his symptoms and no side effects. We review the scarce literature documenting cases of prostate cancer metastatic to the brain or skull base and the only two other documented cases of prostate cancer metastasis the Meckel's cave neither of which was treated with radiotherapy.