脊椎硬膜外膿瘍在大腸直腸癌中並不常見，若未及時找出感染源，延誤癌症治療，可能導致不可挽回的失誤。本案例為一位68歲男性，因左下背痛就診，最初診斷為腰椎退化性關節炎，並接受復健治療。然而，疼痛逐漸加劇，核磁共振顯示第5腰椎和第1薦椎左側有脊椎硬膜外囊腫；但個案拒絕住院。兩週後，疼痛轉為劇烈的雙下背鈍疼痛，且無法行走。評估疼痛未在有夜間加劇和伴隨體重減輕，且休息無法緩解；特徵與椎間盤突出和腫瘤骨轉移的表現較不符。經血清學發現感染指數上升和缺鐵性貧血，進而追蹤糞便潛血試驗為正常，故高度懷疑血流性感染引發脊椎硬膜外膿瘍。由於個案已出現神經功能缺失症狀，隨即接受脊椎手術。術中細菌培養報告為牛鏈球菌，經會診感染科給予Ceftriaxone。進一步尋找感染導因，確立個案罹患大腸直腸癌；隨後接受腫瘤根除手術，並於出院後進行化學治療。經案例經驗，當病人出現持續性下背痛，無明顯加重和緩解因子，尤其伴隨缺鐵性貧血，即使沒有發燒，仍應高度懷疑大腸直腸癌引發的血流性脊椎感染。及早診斷並接受手術治療，可有效避免神經功能缺失及惡性腫瘤轉移，從而降低併發症。

Spinal epidural abscess (SEA) is a rare but serious complication in patients with colorectal cancer(CRC). Delayed identification of the infectious source may postpone oncologic treatment and lead to irreversible complications. This report presents a 68-year-old male who initially presented with left-sided lower back pain and was diagnosed with lumbar spondylosis. He received rehabilitation therapy, but his symptoms progressively worsened. Magnetic resonance imaging revealed an epidur-al cyst involving the left L5 and S1 vertebral levels. The patient initially declined hospitalization. Two weeks later, he developed severe bilateral lower back pain and became unable to walk. The pain lacked typical aggravating or relieving factors and was not associated with nocturnal worsening or weight loss, making herniated disc or spinal metastasis less likely. Laboratory evaluation revealed elevated inflammatory markers and iron deficiency anemia (IDA), though fecal occult blood testing was negative. Given the progressive neurological deficits and clinical suspicion of SEA secondary to hematogenous spread, the patient underwent urgent spinal decompression surgery. Intraoperative wound cultures isolated Streptococcus bovis, and the patient was started on intravenous ceftriaxone after infectious disease consultation. Subsequent investigations confirmed a diagnosis of colorectal cancer. The patient underwent curative tumor resection followed by adjuvant chemotherapy. This case highlights the importance of considering colorectal malignancy as a potential source of hematogenous spinal infection in patients with persistent, non-specific lower back pain and iron deficiency anemia, even in the absence of fever. Early recognition and timely surgical intervention are critical in prevent-ing neurological sequelae and ensuring optimal oncologic outcomes.