腦膿瘍是單核球增多性李斯特菌所導致之中樞神經感染少見的臨床表現，過去在臺灣不曾有單核球增多性李斯特菌腦膿瘍的病例報告。我們報告一位六十五歲男性糖尿病病患，一個月來有間歇性發燒合併右側搏動性頭痛，在此之前曾經因貧血接受類固醇治療兩個月。入院時並無明顯局部神經症狀，腦部電腦斷層檢查顯示右側大腦放射冠有一處腦膿瘍，經食道心臟超音波檢查顯示有主動脈瓣膜贅生物，血液細菌培養呈現單核球增多性李斯特菌。經過使用靜脈抗生素治療後臨床完全消除，後續腦部電腦斷層檢查顯示腦膿瘍已縮小。

Brain abscess is an uncommon manifestation of central nervous system infection caused by Listeria (L.) monocytogenes. We presented a 65-year-old diabetic male patient, who had suffered from intermittent fever with right parieto-occipital throbbing headache for one month. He had been on steroid therapy for anemia for more than two months. No obvious clinical focal neurological deficit was noted on admission. Brain computed tomography (CT) disclosed a brain abscess in the right corona radiata. A transesophageal echocardiogram revealed vegetations on the aortic valves. Blood cultures yielded L. monocytogenes. His clinical symptoms resolved after intravenous ampicillin and gentamicin therapy. Serial follow-up brain CT showed decreased size of the brain abscess. L. monocytogenes is a rare pathogen of brain abscess. No cases of listerial brain abscess have previously been reported in Taiwan.