Is this a case of myelodysplastic syndrome (MDS)?

Is This Classic MDS?

To determine if this is classic MDS, you must confirm the presence of persistent cytopenias with bone marrow dysplasia (≥10% of cells in one or more myeloid lineages) and exclude other causes of cytopenia. 1

Diagnostic Criteria for MDS

The diagnosis of MDS requires meeting specific morphological and clinical criteria:

Essential Diagnostic Features

• Blood cytopenias must be present (anemia, neutropenia, and/or thrombocytopenia) with persistent duration over at least several months 1
• Bone marrow examination showing dysplasia in ≥10% of cells in one or more myeloid lineages is the gold standard for diagnosis 1, 2
• Blast percentage in bone marrow must be documented (<5% for lower-risk subtypes, 5-19% for RAEB) 1
• Cytogenetic analysis of bone marrow cells is mandatory to identify characteristic abnormalities and aid in risk stratification 1

Classic Presentation Features

The "classic" MDS presentation typically includes:

• Elderly patient (median age ~70 years, though >10% are younger than 50) 1
• Hypercellular bone marrow with ineffective hematopoiesis despite peripheral cytopenias 1
• Morphologic dysplasia showing megaloblastoid erythropoiesis, nucleocytoplasmic asynchrony in early myeloid/erythroid precursors, and dysmorphic megakaryocytes 1
• Gradual onset with relatively stable blood counts over months (not acute) 1

Critical Exclusions Required

Before confirming MDS, you must systematically exclude alternative diagnoses:

Mandatory Exclusion Workup

• Nutritional deficiencies: Check RBC folate and serum B12 levels 1
• Medication effects: Review history for drugs causing cytopenia, alcohol use 1
• Other disorders: Rule out autoimmune disorders, renal failure, chronic infections/inflammations, aplastic anemia, and paroxysmal nocturnal hemoglobinuria 1
• Secondary causes: Assess for prior chemotherapy (especially alkylating agents), radiotherapy, or occupational exposures (benzene) 1

WHO Classification Subtypes

If MDS is confirmed, classify according to WHO criteria to guide prognosis and treatment:

• Lower-risk subtypes include refractory cytopenia with unilineage dysplasia (RCUD), refractory anemia with ring sideroblasts (RARS), and some cases of refractory cytopenia with multilineage dysplasia (RCMD) with <5% blasts 1
• Higher-risk subtypes include refractory anemia with excess blasts-1 (RAEB-1,5-9% blasts) and RAEB-2 (10-19% blasts) 1
• Special subtype: MDS with isolated del(5q) presents with anemia, normal/increased platelets, and <5% blasts 1

Common Diagnostic Pitfalls

• Insufficient dysplasia: If dysplasia is present in <10% of cells but a characteristic cytogenetic abnormality exists (such as -7, del(7q), -5, del(5q)), this still qualifies as MDS-Unclassified (MDS-U) 1
• Peripheral blood blasts: If marrow blasts are <5% but peripheral blood shows 2-4% blasts, classify as RAEB-1 1
• Auer rods: Their presence with <5% blood blasts and <10% marrow blasts mandates classification as RAEB-2 1
• Acute presentation: MDS typically has an insidious onset; acute cytopenia suggests alternative diagnoses 3

Risk Stratification After Diagnosis

Once MDS is confirmed, calculate the Revised International Prognostic Scoring System (IPSS-R) score using:

• Marrow blast percentage (most important prognostic factor) 1
• Number and severity of cytopenias 1
• Cytogenetic abnormalities (very good, good, intermediate, poor, or very poor risk categories) 1

Without seeing the actual patient data (blood counts, bone marrow morphology, cytogenetics), it is impossible to definitively confirm if "this" is classic MDS—the diagnosis requires systematic evaluation of all these criteria with appropriate exclusions. 1, 2