Alpha-1 antitrypsin (A1AT) is a common genetic disease caused by a mutation in the SERPINA1 gene, predisposing patients to severe premature lung and liver disease. Higher expression of SERPINA1 has been associated with a poor prognosis in patients with high-grade glioblastoma. We present a woman in her 70s with a history of A1AT deficiency treated with weekly plasma-purified A1AT infusions, who presented with metabolic encephalopathy. A CT scan of the brain obtained during admission revealed a left frontal lobe mass measuring 1.1 cm. A craniotomy and resection of the lesion were performed, and the pathology studies revealed a glioblastoma multiforme, WHO grade IV. She is currently healing and awaiting treatment with temozolomide with concomitant radiation and tolerating treatment well.