Hematology Oncology · Year 2 · from Hematology Oncology
Case 3: Myelodysplastic Syndrome Transforming to AML
Patient Presentation
Demographics: 68-year-old male
Chief Complaint: Worsening fatigue and new bruising
History of Present Illness: The patient was diagnosed with MDS 2 years ago (MDS with ring sideroblasts) and has been monitored without treatment. He now presents with worsening fatigue, new petechiae, and gum bleeding. He reports fevers over the past week.
Past Medical History:
- MDS-RS diagnosed 2 years ago
- Baseline hemoglobin 9.5 g/dL, platelets 120,000/mcL
Physical Examination:
- Temperature: 38.4C
- Blood pressure: 110/68 mmHg
- General: Ill-appearing, pale
- Skin: Petechiae on lower extremities, ecchymoses on arms
- Oral mucosa: Gum bleeding
- No lymphadenopathy
- No hepatosplenomegaly
Workup and Results
Laboratory Studies (Current vs Baseline):
- Hemoglobin: 6.8 g/dL (was 9.5)
- WBC: 1,200/mcL with ANC 300 (was 4,500)
- Platelets: 18,000/mcL (was 120,000)
Peripheral Blood Smear:
- Circulating blasts 8%
- Pseudo-Pelger-Huet cells
- Hypogranular neutrophils
Bone Marrow Biopsy:
- 25% blasts (was 3% two years ago)
- Dysplasia in all lineages
- Ring sideroblasts still present (15%)
- Cytogenetics: Complex karyotype with del(7), del(5q)
Clinical Image
Bone marrow aspirate demonstrating increased myeloblasts (>20%) indicating transformation from MDS to AML. Note the background dysplastic cells including hypolobated megakaryocytes.
Diagnosis
AML with Myelodysplasia-Related Changes (Previously MDS-RS)
Transformation criteria met:
- Blast count ≥20% (defines AML)
- Prior MDS history
- MDS-related cytogenetic abnormalities
- Multilineage dysplasia
Discussion
This case illustrates MDS transformation:
- Blast Threshold: The lecture identifies 20% blasts as the threshold distinguishing MDS from AML. This patient's blasts increased from 3% to 25%, indicating transformation.
- MDS Progression Risk: The lecture notes that approximately 30% of MDS patients transform to AML. Higher-risk IPSS-R scores predict faster transformation.
- TP53 and Complex Karyotype: The lecture identifies complex karyotype and TP53 mutations as very poor prognostic factors associated with rapid transformation and treatment resistance.
- Ineffective Hematopoiesis: The lecture describes how MDS is characterized by ineffective hematopoiesis - the marrow is cellular but cells die prematurely (apoptosis), causing cytopenias despite adequate production.
Treatment Plan
- Immediate Supportive Care:
- Transfusion support (pRBC, platelets)
- Broad-spectrum antibiotics for febrile neutropenia
- Growth factor support (G-CSF) if needed
- Treatment Decision:
- Intensive chemotherapy if fit and no prohibitive comorbidities
- OR hypomethylating agent (azacitidine, decitabine) if not fit
- OR venetoclax + azacitidine combination
- Transplant Evaluation:
- Allogeneic stem cell transplant consideration
- Best long-term option if eligible
- Prognosis Discussion:
- AML arising from MDS has worse outcomes
- Complex karyotype particularly poor
- Goals of care discussion appropriate
Teaching Points
- 20% blasts = transformation from MDS to AML
- ~30% of MDS patients transform to AML
- Complex karyotype and TP53 mutations confer very poor prognosis
- MDS is characterized by ineffective hematopoiesis (cytopenia despite cellular marrow)
- Allogeneic transplant is potentially curative but limited by age/fitness
Image Reference
For visual reference of MPN and MDS concepts, see:
- Radiopaedia: Myelofibrosis - Imaging
- Wikipedia: Polycythemia vera - Clinical features
- Radiopaedia: Myelodysplastic syndrome - Blood smear
Learning Points
- JAK2 in PV: Present in 95%; EPO is suppressed (distinguishes from secondary)
- PV Hematocrit Target: <45% to reduce thrombosis risk
- Myelofibrosis Features: Dry tap, tear-drop cells, leukoerythroblastosis, extramedullary hematopoiesis
- MDS to AML: 20% blasts defines transformation; occurs in ~30% of MDS patients
- Only Cure: Allogeneic transplant is only curative option for myelofibrosis and high-risk MDS/AML