A 69-year-old male presented with a diagnosis of idiopathic pericarditis, first treated with prednisone for a few weeks with resolution of the symptoms. A few days after stopping the medication, he presented with malaise, cough and signs of pericardial constriction confirmed by echocardiography. He was diagnosed with pulmonary tuberculosis with pericardial involvement and treated accordingly. Pericardiectomy was performed after a few days of treatment because the symptoms related to constriction progressed. The procedure was successful, and the patient was completely asymptomatic after 10 months. The removed pericardium stained positive for acid-fast bacilli.