Mycobacterium kansasii pneumonia with mediastinal lymphadenitis in a patient with acute myeloid leukemia: Successful treatment to stem cell transplantation

Non-tuberculous mycobacterial (NTM) disease is a relatively rare cause of neutropenic fever in patients with hematologic malignancies. During the neutropenic period, performing invasive procedures for microbiological or pathological confirmation is difficult. In addition, the optimal treatment duration for NTM disease in patients with leukemia, especially prior to stem cell transplantation (SCT), has not been documented. Therefore, we report a case of pneumonia with necrotizing lymphadenitis caused by Mycobacterium kansasii diagnosed during chemotherapy being performed for acute myeloid leukemia. The radiologic findings were similar to those of invasive fungal pneumonia; however, a bronchoalveolar washing fluid culture confirmed that the pathogen was M. kansasii. After 70 days from starting NTM treatment, allogeneic SCT was performed without any complications. The patient fully recovered after 12 months of NTM treatment, and neither reactivation of M. kansasii infection nor related complications were reported.