• Clinical science

Myelodysplastic syndromes

Summary

Myelodysplastic syndromes (MDS) are a group of hematological cancers in which malfunctioning pluripotent stem cells lead to hypercellularity and dysplasia of the bone marrow. This, in turn, leads to cytopenia of one or more cell lines (thrombocytopenia, erythrocytopenia, leukocytopenia). Most cases of MDS have a primary, idiopathic etiology, while a minority of cases are secondary to an underlying cause. MDS usually affects elderly patients and has a slowly progressive course. Clinical features vary depending on the type of MDS and the affected cell lines, and may include signs of anemia (e.g., fatigue, weakness, pallor), recurrent infections, and/or petechial bleeding. Diagnosis of MDS requires blood tests, bone marrow biopsy, and possibly genetic analysis. While mild cases may be closely monitored, severe disease typically requires blood transfusions supplemented with erythropoietin, vitamins, and, in some cases, granulocyte colony-stimulating factor. Medical therapy (e.g., chemotherapy or immunosuppressants) may also help to manage the disease, but allogenous stem cell transplantation is the only curative treatment. In 30% of cases, the disease progresses to acute myeloid leukemia.

Etiology

Classification

WHO Classification of Primary Myelodysplastic Syndromes [3][4]

  • The WHO classification distinguishes between six types of myelodysplastic syndromes, based on the number of dysplastic cell lines and the percentage of blasts in the bone marrow, among other criteria:
    • MDS with multilineage dysplasia (MDS-MLD; most common)
    • MDS with single lineage dysplasia (MDS-SLD)
    • MDS with ring sideroblasts (MDS-RS), with two subtypes:
      • MDS-RS with single lineage dysplasia (MDS-RS-SLD)
      • MDS-RS with multilineage dysplasia (MDS-RS-MLD)
    • MDS with excess blasts (MDS-EB), with two subtypes:
      • MDS-EB1
      • MDS-EB2
    • MDS with isolated del(5q) (rare)
    • MDS, unclassifiable (MDS-U; very rare)
  • WHO also has a clinical classification
    • Primary MDS: no identifiable cause
    • Secondary MDS: cause is known

Clinical features

Diagnostics

Treatment

The therapeutic approach depends on a patient's presentation, age, and comorbidities. More aggressive therapy (e.g., chemotherapy, stem cell transplantation) is generally reserved for younger, healthier patients. [7]

Complications

We list the most important complications. The selection is not exhaustive.