A 78-year-old man was referred to our hospital for suspected small intestinal cancer with pleural effusion on computed tomography. We performed colonoscopy and found some ulcers in the terminal ileum, but pathological examination showed no malignant findings. We suspected tuberculous pleural effusion and small bowel tuberculosis because of a positive T-SPOT result. We performed repeat colonoscopy and examination of the pleural effusion with an added culture test. The patient was started on anti-tuberculosis drugs, though polymerase chain reaction was negative for acid-fast bacillus. However, Mycobacterium tuberculosis were cultured after 8 weeks. We diagnosed tuberculous pleural effusion and small bowel tuberculosis, and colonoscopy 6 months later showed that the ulcers had improved. Small bowel tuberculosis has become rare, but it is important as a differential diagnosis.
