Aneurysmal subarachnoid hemorrhage, a presentation of metastatic carcinoma: A case report and review of the literature

BACKGROUND: Neoplastic cerebral aneurysms related to metastatic processes are exceptionally rare and carry a dismal prognosis. Only four previous reports exist of neoplastic aneurysms secondary to metastatic adenocarcinoma, all of which were found to be lung cancer in origin. We present the fifth reported metastatic adenocarcinomatous cerebral aneurysm, and the first case is secondary to a non-lung cancer primary. CASE DESCRIPTION: The patient presented with complaining of headache and was found to have a large right-sided intraparenchymal hemorrhage and smaller left-sided hemorrhage on head CT, and CTA revealed a vascular pouch in the region of the hemorrhage. The patient showed sudden neurologic decline, and repeat imaging revealed enlargement of the hematoma with significant brain compression. The patient underwent emergent angiography revealing a distal cortical middle cerebral artery aneurysm, suspicious for mycotic etiology, which was treated through microsurgical excision at the time of hematoma evacuation. The aneurysm specimen was sent for cultures and pathology, revealing the diagnosis of metastatic non-small-cell carcinoma. Further inpatient workup did not reveal the primary neoplastic source. CONCLUSION: Although diagnostic workup should search for more common pathologic mimics than metastatic neoplastic cerebral aneurysms, clinicians must be able to recognize and expeditiously treat this devastating lesion. Further investigation and analysis of treatment options are necessary to better understand this rare pathology and improve patient outcomes.