Periampullary Carcinoma Presenting as Chronic Subdural Hematoma: A Rare Case Report.

Skull metastases usually arise from breast and lung primaries and are often silent. Spread from periampullary carcinoma is exceedingly rare. We present a 46-year-old female with a history of periampullary carcinoma, previously treated with surgery and chemotherapy, who presented with headache, vomiting, and declining consciousness. At admission, she was in a stuporous state. Computed tomography (CT) revealed a large right frontoparietal subdural hematoma (SDH) with midline shift. Emergency burr hole evacuation exposed fragile bone and hemorrhagic tissue; biopsy confirmed metastatic adenocarcinoma. Retrospective review of bone windows revealed lytic lesions consistent with skull metastasis. This appears to be the first documented case of periampullary carcinoma metastasizing to the skull and presenting as spontaneous SDH, without trauma, coagulopathy, or anticoagulant use. Early recognition with magnetic resonance imaging and positron emission tomography-CT is vital. This case highlights the importance of considering skull metastasis as an etiology of intracranial hemorrhage in oncologic patients.