RESUMO
Tuberculosis is an indolent infection that can invade any organ. Although the most frequent form of presentation is pulmonary, it can have an extra-pulmonary presentation, including rare cases of oral tuberculosis. We present a clinical case of a 44 year-old man, active smoker, with an ulcerated lesion on the posterior third of the tongue, initially interpreted as a probable neoplasm. The pathological study of the biopsy performed on the lesion, showed alterations compatible with a chronic granulomatous process and the presence of acid-fast bacilli. The concomitant diagnosis of pulmonary tuberculosis was made in a subsequent study. The patient started therapy with isoniazid, rifampin, pyrazinamide and ethambutol with complete resolution of the oral lesion and pulmonary tuberculosis. This case exemplifies the importance of including tuberculosis in the differential diagnosis of ulcerated and neoformative lesions and the value of performing a microbiological study alongside the pathological one.