A 65-year-old man presents with fatigue and recurrent bacterial infections. CBC shows normocytic anemia, thrombocytopenia, and a WBC of 3,200/µL. Bone marrow biopsy reveals hypercellularity with dysplastic megakaryocytes showing hypolobated nuclei and ringed sideroblasts comprising 20% of erythroid precursors. Cytogenetics show deletion 5q. Which MDS subtype does this most likely represent?

• A MDS with excess blasts-2 (MDS-EB2)
• B MDS with multilineage dysplasia and ring sideroblasts (MDS-MLD-RS) ✓
• C MDS with ring sideroblasts and single lineage dysplasia (MDS-RS-SLD)
• D MDS with isolated del(5q)

Explanation

The presence of dysplasia in multiple lineages (erythroid with ring sideroblasts AND megakaryocytic with hypolobated nuclei), ring sideroblasts ≥15% of erythroid precursors, and del(5q) in this context points to MDS with multilineage dysplasia and ring sideroblasts. MDS with isolated del(5q) classically shows macrocytic anemia with normal/high platelets and unilineage dysplasia of erythroid cells with hypolobated megakaryocytes — the del(5q) there is the defining abnormality with that specific phenotype. MDS-EB requires 5–19% blasts.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.