[Traps of tuberculosis among the aged: an astonishing cyst of left foot].

We report the case of a 75 years old man who insidiously developed a unusual presentation of tuberculosis. The story began with a tuberculous arthritis of the foot, later associated with pulmonary, endobronchial, mediastinal and cervical lymphadenitis tuberculosis. Because the microscopic examination was negative for acid-fast bacilli (AFB) in all involved sites, the diagnosis of sarcoidosis was suggested.