Leptomeningeal involvement by prostate carcinoma an ominous head of a well-known Hydra.

A 67-year-old male patient presents to the hospital complaining of severe nausea and vomiting failing oral antiemetics. He carries the history of initial diagnosis of stage III prostate cancer. He underwent radical prostatectomy followed by external beam radiation. After 5 years of initial excellent control with androgen deprivation therapy (ADT), imaging study showed retroperitoneal adenopathy denoting ADT failure. His prostate-specific antigen continued to rise while on enzalutamide and then abiraterone reflecting disease progression. He maintained excellent functional capacity through 23 cycles of docetaxel however he started developing hip pain after the last cycle with imaging studies suggesting new hip metastatic disease. Following the first cycle of radium-223, the patient presented with intractable nausea and vomiting. MRI showed a high suspicion of leptomeningeal spread which was confirmed through a meningeal biopsy after lumbar puncture showed negative results. The patient had excellent symptomatic response to high-dose dexamethasone. After receiving whole-brain radiation, the patient opted to be on best supportive care and succumbed to his illness 3 months later.