A case of silicosis with <i>Mycobacterium avium</i> infection relapsed with lymphadenitis 1 year after the completion of initial treatment

A 71-year-old man with silicosis was treated for <i>Mycobacterium avium</i> infection. Antimycobacterial treatment for <i>M. avium</i> was terminated 1 year after a negative test result for the bacteria on sputum examination. One year following the treatment, the patient developed pneumonitis. In the sputum culture, growth of <i>M. avium</i> was not detected. Pneumonitis did not improve despite sufficient antibacterial therapy. Chest computed tomography scan revealed aggravated shadows of pneumonitis and swelling of supraclavicular lymph nodes. A lymph node biopsy was performed, and polymerase chain reaction testing revealed <i>M. avium</i> infection. We diagnosed the patient with pneumonitis and lymphadenitis due to recurrent <i>M. avium</i> infection. Antimycobacterial treatment with rifampicin, ethambutol, clarithromycin, and amikacin was initiated. Pneumonitis and the general status of the patient improved following the treatment. Lymphadenitis is rare in adults in the absence of any immunodeficiency condition. We speculate that silicosis is a risk factor for mycobacterial infection recurrence.