Chronic myeloid leukemia and monoclonal gammopathy of unknown significance: a case report and literature review

Objective To explore the characteristics of chronic myelogenous leukemia (CML) combined with monoclonal immunoglobulinemia of unknown significance (MGUS). Methods A CML patient with MGUS was reported, who was admitted to the Affiliated Hospital of Xuzhou Medical University. His clinical data were collected and relevant literature was reviewed. Results The patient was first admitted to the hospital on July 2019. According to serum fixed electrophoresis and protein electrophoresis, his monoclonal immunoglobulin (M protein) was positive and immunoglobulin (IgA) was weakly positive. Bone marrow morphology examination showed abnormal morphology in 3.5% of plasma cells. Abnormal monoclonal plasma cell population was detected by flow cytometry. Rearrangement of immunoglobulin heavy chain (IgH) (62/300) was found by fluorescence in situ hybridization (FISH). Chromosome karyotype analysis showed 46, XY, t (9 ; 22) (q34; q11)10 46, XY1. The patient was diagnosed with MGUS, while CML was not determined. After anti-infection, folic acid supplementation, antidiarrheal and other symptomatic treatments, his symptoms were relieved. He refused fusion gene examination and was discharged. On March 2020, the patient was admitted to the hospital again and the fusion gene analysis found 40.98% positive BCR/ABL1 (P230). FISH assay showed BCR/ABL1 (270/300), while abdominal color Doppler ultrasound revealed normal spleen size. The patient was diagnosed with BCR/ABL1 (P230) positive CML without large spleen complicated with MGUS. This patient received symptomatic and supportive treatment such as anti-infection, iron supplementation, and stomach protection, and treated CML with imatinib mesylate. The patient is currently in a stable condition. Conclusions CML combined with MGUS is rarely reported and easily misdiagnosed. Further studies are required for determining the treatment strategies and mechanisms of CML and MGUS.