SURG-29. Amphicrine brain metastasis from prostate cancer and the role of surgical intervention: an illustrative case

Abstract Prostate cancer is the second most commonly diagnosed cancer in men worldwide, particularly in men 65 years and older. It has a high proclivity for metastasis to the bones, lymph nodes, and liver. Contrary to breast or lung cancer, prostate cancer (PC) metastasis to brain parenchyma is exceedingly rare, accounting for fewer than 1% of all brain metastases. Histologic classifications of PC metastasis subtypes continue to be refined in the literature, and the role of surgical management of PC metastases to the brain is evolving. There is a relative paucity of data regarding treatment recommendations for aggressive PC subtypes such as amphicrine carcinoma, which has both adenocarcinoma and neuroendocrine differentiation. This case report represents a rare instance of an intraparenchymal amphicrine PC metastasis. A 77-year-old right-handed man presented to the emergency department with transient aphasia, initially concerning for stroke. MRI revealed a 2 cm enhancing mass of the left middle temporal gyrus, with high-grade glioma leading the differential diagnosis based on imaging characteristics. His past medical history was notable for prostate adenocarcinoma metastatic to bone, lymph nodes, and liver. He underwent an awake craniotomy for gross total resection and discharged two days later. Final pathology revealed an amphicrine PC brain metastasis. He was treated with adjuvant gamma knife radiation, then resumed systemic chemotherapy and ADT. At 3 months, his functional status remained stable, and MRI showed no recurrence. Prostate cancer very rarely metastasizes to brain parenchyma. However, in a patient with prostate cancer and known metastases to bones or visceral organs, the differential for a new brain mass should include prostate metastasis. In these cases, surgical intervention must be considered in conjunction with radiotherapy, with particular attention to high grade subtypes of PC.