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Myelodysplastic Syndrome (MDS)

Myelodysplastic Syndrome (MDS) is a group of clonal bone marrow disorders characterized by ineffective hematopoiesis, leading to one or more cytopenias and an increased risk of progression to Acute Myeloid Leukemia (AML)

Also called

Preleukemia (historical term)

ICD-10

D46

Specialty

Hematology

Onset

Chronic

Reviewed

August 2026

On This Page

Overview

Myelodysplastic Syndrome (MDS) is a clonal stem cell disorder in which the bone marrow produces dysplastic and ineffective blood cells, resulting in anemia, neutropenia, thrombocytopenia, or pancytopenia. Although the bone marrow is usually hypercellular, many abnormal cells undergo apoptosis before entering the circulation. Some patients remain stable for years, while others progress to AML.

Etiology & Risk Factors

Myelodysplastic Syndrome (MDS) develops from acquired genetic mutations in hematopoietic stem cells causing ineffective blood cell production.

-Risk Factors

  • Increasing age (>60 years)
  • Previous chemotherapy (therapy-related MDS)
  • Previous radiotherapy
  • Benzene exposure
  • Smoking
  • Congenital bone marrow failure syndromes
  • Family history (rare)

Pathophysiology

Acquired mutations in hematopoietic stem cells → abnormal clonal proliferation → ineffective hematopoiesis with dysplastic maturation → increased apoptosis of developing blood cells → peripheral cytopenias despite a hypercellular bone marrow → accumulation of additional mutations may lead to transformation into Acute Myeloid Leukemia (AML).

Clinical Presentation

Symptoms

  • Fatigue

  • Weakness

  • Dyspnea on exertion

  • Recurrent infections

  • Fever

  • Easy bruising

  • Bleeding

  • Weight loss (advanced disease)

Signs

  • Pallor

  • Petechiae

  • Purpura

  • Ecchymoses

  • Fever

  • Signs of infection

Splenomegaly and lymphadenopathy are uncommon.

History Taking

-Ask about:

  • Fatigue
  • Bleeding
  • Recurrent infections
  • Previous chemotherapy
  • Previous radiotherapy
  • Chemical exposure
  • Smoking
  • Weight loss
  • Family history
  • Previous hematological disorders

Physical Examination

General Examination

Look for:

  • Pallor

  • Fever

  • Petechiae

  • Ecchymoses

  • Signs of infection

Systemic Examination

Assess for:

  • Hepatosplenomegaly (rare)

  • Lymphadenopathy (uncommon)

  • Bleeding manifestations

Investigations

-Complete Blood Count (CBC)

Typical findings:

  • Anemia (most common)

  • Neutropenia

  • Thrombocytopenia

  • Pancytopenia (some patients)

-Peripheral Blood Film

May show:

  • Macrocytosis

  • Dysplastic neutrophils (hypogranular or hyposegmented/Pseudo-Pelger-Huët cells)

  • Giant or hypogranular platelets

  • Circulating blasts (advanced disease)

-Bone Marrow Aspiration and Biopsy (Gold Standard)

Typical findings:

  • Usually hypercellular marrow

  • Dysplasia in one or more cell lines

  • Increased blasts (less than 20%)

  • Ring sideroblasts (selected subtypes)

-Cytogenetic & Molecular Studies

Common abnormalities:

  • del(5q)

  • Monosomy 7

  • Trisomy 8

  • Complex karyotype

  • TP53 mutation

  • SF3B1 mutation

-Additional Investigations

To exclude other causes of cytopenias:

  • Vitamin B12

  • Folate

  • Iron studies

  • Reticulocyte count

  • Liver function tests

  • Renal function tests

  • Hemolysis screen

Prognostic Assessment

  • Revised International Prognostic Scoring System (IPSS-R)

  • IPSS-M (molecular scoring system)

Diagnosis

Diagnosis is based on:

  • Persistent unexplained cytopenias
  • Bone marrow dysplasia
  • Blast percentage (<20%)
  • Cytogenetic and molecular abnormalities
  • Exclusion of other causes of cytopenias
  •  
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Management

-Lower-Risk MDS

  • Observation (selected asymptomatic patients)

  • Blood transfusions as needed

  • Erythropoiesis-stimulating agents (ESAs)

  • Iron chelation therapy (transfusion-dependent patients)

  • Lenalidomide for isolated del(5q)

  • Luspatercept for selected patients with ring sideroblasts

-Higher-Risk MDS

  • Hypomethylating agents

    • Azacitidine

    • Decitabine

  • Intensive chemotherapy (selected patients)

  • Allogeneic hematopoietic stem cell transplantation

-Curative Treatment

  • Allogeneic hematopoietic stem cell transplantation (only curative therapy)

-Supportive Care

  • Blood transfusions

  • Platelet transfusions

  • Infection prevention

  • Growth factors (selected patients)

  • Prompt treatment of infections

Complications

  • Severe anemia
  • Recurrent infections
  • Major bleeding
  • Iron overload from repeated transfusions
  • Progression to Acute Myeloid Leukemia (AML)
  • Treatment-related complications

Prognosis

The prognosis depends on the degree of cytopenias, blast percentage, cytogenetic abnormalities, and molecular mutations. Lower-risk MDS may remain stable for years, whereas higher-risk disease has a significant risk of progression to AML. Prognosis is commonly assessed using the IPSS-R or IPSS-M scoring systems.

Key Points / Clinical Pearls

  • Myelodysplastic Syndrome (MDS) is a clonal bone marrow disorder causing ineffective hematopoiesis.
  • Patients present with persistent cytopenias, especially anemia.
    Bone marrow is usually hypercellular with dysplasia.
  • Blast count is <20% (≥20% suggests AML).
    Bone marrow biopsy with cytogenetics confirms the diagnosis.
    del(5q) predicts response to lenalidomide.
  • Azacitidine is the standard treatment for many higher-risk patients.
  • Allogeneic stem cell transplantation is the only curative therapy.
  • MDS has a variable prognosis based on IPSS-R/IPSS-M.
    The major long-term complication is progression to Acute Myeloid Leukemia (AML).
  • Dotson JL, Lebowicz Y. National Center for Biotechnology Information (NIH). Myelodysplastic Syndrome, StatPearls.
  • Arber DA, Orazi A, Hasserjian RP, et al. International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: Integrating Morphologic, Clinical, and Genomic Data. Blood. 2022;140:1200-1228.
  • Fenaux P, Haase D, Santini V, Sanz GF, Platzbecker U, Mey U. Myelodysplastic Syndromes: ESMO Clinical Practice Guidelines for Diagnosis, Treatment and Follow-Up. Ann Oncol. 2021;32:142-156.
  • Bernard E, Tuechler H, Greenberg PL, et al. Molecular International Prognostic Scoring System for Myelodysplastic Syndromes. NEJM Evid. 2022;1:EVIDoa2200008.
  • MedlinePlus, National Library of Medicine (NIH). Myelodysplastic Syndromes: Health Topic.