We present the case of a 40-year-old immunocompetent man with complaints of perianal abscess, diarrhea, and weight loss for 3 months. He denied respiratory symptoms. Colonoscopy revealed ulcers and histopathology showed non-necrotizing granulomas and excluded acid-fast bacilli. Initially, the clinical and histological findings favored the diagnosis of Crohn's disease, however, further investigation by performing chest radiography in the context of a pre-immunomodulatory checklist, revealed pulmonary cavitations confirmed on computed tomography scan. Further mycobacteriological studies suggested the diagnosis of active pulmonary tuberculosis. Demonstration of the presence of Mycobacterium tuberculosis in the colon was possible by RT-PCR. Complete resolution of intestinal and perianal symptoms was achieved 2 weeks after treatment with anti-bacillary agents.