RESUMEN
A 63-year-old man was diagnosed with advanced sigmoid cancer of pT3, pN0, sM1c, sP3, fStage â £ post-operation. After CAPOX plus Bmab as the first-line chemotherapy, he underwent IRIS plus Bmab as the second-line chemotherapy. After 1 course of IRIS plus Bmab, he was admitted to the hospital for fever, dyspnea, and general fatigue. The white blood cell count was 6.2×10 3/mL, and the C-reactive protein was elevated to 12.9 mg/dL. The PaO2 of the artery blood gas analysis in room air was 46.3 mmHg, suggesting respiratory failure. He was diagnosed with PCP based on the bilateral diffused ground-glass opacities on chest CT along with an elevated serum b-D-glucan. The treatment of trimethoprim-sulfamethoxazole and steroid was then initiated. After the patient's clinical condition improved, he was discharged on day 27 post-admission.