Abstract: Objective: To investigate the clinical characteristics and differential diagnosis of chronic myelomonocytic leukemia (CMML) accompanied with non-Hodgkin 's lymphoma (NHL). Methods: The clinical data, imaging findings, pathomorphological features and immunohistochemical markers of two patients with CMML accompanied with NHL were retrospectively analyzed, and related literatures were reviewed. Results: The 2 cases were elderly women presented with fatigue or symptoms of tumor invasion at corresponding sites. Case 1 was diagnosed with CMML and thereafter having NHL diagnosed, and case 2 was diagnosed with CMML and NHL simultaneously. Laboratory examination showed that peripheral white blood cells were increased,especially mononuclear cells, and lactate dehydrogenase was also increased. Bone marrow smears showed active proliferation with morbid hematopoiesis. On immunophenotyping, the bone marrow cells often expressed CD14⁺CD64⁺. Analysis of chromosome fluorescence in situ hybridization showed that BCR-ABL fusion gene were negative. PET/CT examination displayed that high metabolic lesions in bone marrow were not found in the 2 cases, but showed hypermetabolic small intestinal lesions in case 1 and lung lesions in case 2. SUVmax value were 12.60 and 6.72, respectively. Pathological examination suggested that these 2 patients were B-cell-derived NHL. Immunohistochemical study showed that LCA, CD20, CD79a, Bcl-6 and Ki-67 were positive, CD5, CD10, CD3, CylinD1, CD56, CD23 and CD21 were negative. Conclusions: CMML accompanied with NHL is rare and lacks specific clinical manifestation. With the laboratory findings combined with imaging, histopathology and immunohistochemical examination, the diagnostic accuracy could be improved.

Key words: Chronic myelomonocytic leukemia, Non-Hodgkin 's lymphoma, Diagnosis