Monocytic nodules are a common feature in biopsies.The phenotypical characteristics of CMML are; CD11b, CD11c, CD14, CD33, CD45 and CD64 seen in 100% of cases; CD13 found in 95% of cases; CD4 found in 76% of cases; HLA-DR found in 71% of cases; CD56 found in 53% of cases; CD2 found in 34% of cases; CD16 found in 29% of cases; CD10 found in 28% of cases; CD23 and CD7 found in 9% of cases; and CD117 found in 5% of cases. Classification
Leukemia subtypes are categorised into single clinical entities so that they can be diagnosed and treated appropriately. Leukaemias are subdivided into lymphoid and myeloid neoplasms, depending on which bone marrow cells are cancerous. The myeloid neoplasms contain acute and chronic leukemias, myelodysplastic syndromes (MDSs) and myeloproliferative neoplasms (MPNs). MPNs are characterised by increased production of myeloid blood cells, with a higher than normal number of mature cells. Unlike MPNs, MDSs have a dysfunctional production of myeloid cells with a reduced number of mature cells. Many of the cells produced in MDS are abnormal looking, known as dysplasia. CMML shows characteristics of both groups and thus is a difficult disease to categorise. FAB classification
The French-American-British (FAB) classification system was published in 1976 to classify the leukaemias. It placed CMML into the category of MDS, along with the refractory anaemia, refractory anaemia with ring sideroblasts, refractory anaemia with excess blasts and refractory anaemia with excess blasts in transformation.
Chronic myelomonocytic leukemia (CMML) is a type of leukemia, which are cancers of the blood-forming cells of the bone marrow. In adults, blood cells are formed in the bone marrow, by a process that is known as haematopoiesis. In CMML, there are increased numbers of monocytes and immature blood cells (blasts) in the peripheral blood and bone marrow, as well as abnormal looking cells (dysplasia) in at least one type of blood cell.CMML shows characteristics of a myelodysplastic syndrome (MDS); a disorder that produces abnormal looking blood cells, and a myeloproliferative neoplasm (MPN); a disorder characterised by the overproduction of blood cells. For this reason, CMML was reclassified as a MDS/MPN overlap disorder in 2002. For a diagnosis of CMML, the World Health Organization (WHO) states that the blood monocyte count must be >1x109/L, no Philadelphia chromosome or mutations in the PDGFRA or PDGFRB gene should be present, the blast count must be <20% and dysplasia of at least one lineage of myeloid blood cell should be present.Azacitidine is a drug used to treat CMML and is approved by the Food and Drug Administration (FDA) and the European Medicines Agency. Stem cell transplant is also used to treat CMML, and involves the transplantation of donor haematopoietic stem cells into the recipient. Blood transfusion and erythropoietin are used to treat disease associated anaemia. Signs and symptoms
One of the most common signs of CMML is splenomegaly, found in approximately half of cases.