Unusual Presentation of Chronic Myelogenous Leukemia Concomitant with Mycobacterium Avium Complex Infection.

Only rare cases of patients with chronic myelogenous leukemia (CML) with disseminated Mycobacterium avium complex (MAC) infection are reported in the literature. In the majority of those cases, MAC infection was diagnosed after at least 12 months and following busulfan or high dose steroids therapy. In many of those cases, disseminated MAC infection was preceded by clinically evident pulmonary disease, including interstitial pneumonia and/or pulmonary alveolar proteinosis. We report a highly unusual case of CML presenting with concomitant disseminated MAC infection in a HIV-negative host with no known preexisting active pulmonary disease.

A 41-year-old Caucasian male without significant past medical history presented to the emergency department with a ten-day history of progressively worsening abdominal pain. He reported generalized weakness, fever, chills, night sweats, decreased appetite and weight loss. His laboratory data were significant for thrombocytosis of 992,000/uL, mild anemia, and a normal white blood cell count of 10,000/uL. He had marked splenomegaly, hepatomegaly, and lymphadenopathy. Bone marrow aspiration was markedly hypercellular with normal myeloid to erythroid ratio, no increase in blasts, mild eosinophilia, moderate fibrosis, and focal necrosis. Routine cytogenetic study revealed t(9;22)(q34;q11). Acid fast bacillus (AFB) culture was positive for MAC, confirmed by DNA probe. Flow cytometry revealed normal CD4:CD8 ratio of T-lymphocytes. There was no evidence of HIV infection by serologic and molecular studies. Therapy with ethambutol and azythromycin was initiated. The patient’s course was complicated by severe pancytopenia, bleeding episodes, and dyspnea. A repeat bone marrow examination revealed severe myelofibrosis with decrease of cellularity and foamy macrophages positive for AFB. Bronchioalveolar lavage demonstrated AFB positive for MAC DNA probe. He required multiple blood product transfusions. Rifampin, Amikacin, Levaquin, imatinib and GM-CSF were added to his therapy. Five months after his initial presentation the patient developed a new lung infiltrate on chest radiography and subsequently underwent video-assisted thoracoscopy with lung biopsy, reveling Aspergillus fumigatus infection. Voriconazole therapy was added. The patient continued to decline and expired six months after his initial presentation.

In summary, this was an atypical presentation of CML without leukocytosis or granulocytic hyperplasia in the bone marrow. While the bone marrow findings were consistent with a chronic myeloproliferative disease, they were more typical of chronic idiopathic myelofibrosis rather than CML. Yet, the cytogenetic study documented the presence of Philadelphia chromosome, diagnostic for CML. It is possible that the underlying MAC infection was responsible for the atypical features. This case illustrates the fact that patients with CML can be at risk for MAC or other atypical mycobacterial infections even prior to chemotherapy. The mechanism of immunosuppression in CML has not been satisfactory explained.