CHAPTER 17: Myelodysplastic Syndromes

MDSs are a group of heterogeneous myeloid hematopoietic disorders characterized by ineffective hematopoiesis and increased risk of transformation to acute myelogenous leukemia (AML). Most patients with MDS die of causes related to the disease. The median age of patients with MDS is 70–75 years.¹

A 71-year-old man is admitted to a hospital with generalized weakness and dyspnea on exertion. On physical examination, the abdominal reveals no organomegaly. His hemoglobin level is 6 g/dL, and the rest of his blood work is normal. There is no obvious evidence of blood loss. A bone marrow examination shows normocellular marrow with dysplastic changes in the megakaryocytes and erythroid series. Increased promyelocytes with granules (14.6%), eosinophils (5.6%), and basophils (7%) are observed. Karyotype is normal (46,XX). Diagnosis is MDS with eosinophilia and basophilia (refractory cytopenia with multilineage dysplasia).

Review whether a patient diagnosed with MDS meets minimal diagnostic criteria²:

• Stable cytopenia (6 months, or 2 months if there is a specific MDS karyotype or bilineage dysplasia)

• Exclusion of other disorders as cause of cytopenia and/or dysplasia or both

• At least 1 of the 3 MDS-related (decisive) criteria:

  • Dysplasia (>10% in ≥1 of 3 major bone marrow lineages)

  • A blast count of 5%–19%

  • Specific karyotype, such as del(5q), del(20)q, +8, or –7del (7q)

• Co-criteria help to confirm diagnosis:

• Abnormal bone marrow immune histology, immunohistochemistry

• Abnormal flow cytometry

• Abnormal CD34 expression

  • Fibrosis

  • Myeloid clonality

  • Dysplastic megakaryocytes

MDS is usually suspected when there is cytopenia in a routine peripheral blood count. A bone marrow aspiration and biopsy follows, with a manual count of blasts, which is essential for risk assessment. Cytogenetic analysis assists in predicting risk and selecting therapy. Risk is calculated using the International Prognostic Scoring System (IPSS). Patients with low and intermediate-1 (INT-1) scores are treated to improve transfusion needs. Patients with higher scores, intermediate-2 (INT-2) or higher, are treated with interventions patterned after AML therapy. The revised IPSS score (IPSS-R) includes a new cytogenetic risk classification that divides patients into 5 categories. It is used more for prognosis than for deciding therapy, since all the approved treatments for MDS have been approved in clinical trials using the IPSS.

• IPSS criteria are used to decide therapy and IPSS-R criteria to evaluate prognosis

1. Montalban-Bravo G, Garcia-Manero G. Myelodysplastic syndromes: 2018 update on diagnosis, risk-stratification and management. Am J Hematol 2018;93:129-47.

2. Valent P, Horny HP, Bennett JM, et al. Definitions and standards in the diagnosis and treatment of the myelodysplastic syndromes: consensus statements and report from a working conference. Leuk Res 2007;31(6):727-36.

A clear picture of the MDS patient’s clinical status is essential for diagnosis, prognosis, and to establish treatment.^...