How to proceed with a 2-year-old presenting with thrombocytosis, anemia, and tear drop cells on peripheral smear?

Evaluation and Management of a 2-Year-Old with Thrombocytosis, Anemia, and Tear Drop Cells

A bone marrow examination is urgently needed for this child with thrombocytosis, anemia, and tear drop cells on peripheral smear, as these findings strongly suggest an underlying myeloid neoplasm requiring prompt diagnosis. 1

Clinical Assessment of Current Presentation

The child presents with:

• Thrombocytosis (platelet count 878,000/μL)
• Anemia (Hb 8.8 g/dL)
• Leukocytosis (TLC 14,800/μL)
• Tear drop cells on peripheral smear
• Normal temperature
• Normal chest X-ray
• Non-reactive CRP

Significance of These Findings

• Tear drop cells are a critical finding that suggests bone marrow pathology, specifically potential myelodysplastic syndrome (MDS), myeloproliferative neoplasm (MPN), or bone marrow fibrosis 1
• Thrombocytosis of this magnitude (>850,000/μL) is rarely reactive in nature when combined with anemia and tear drop cells
• Anemia with tear drop cells suggests potential bone marrow infiltration or fibrosis

Diagnostic Algorithm

Step 1: Immediate Investigations

• Bone marrow aspiration and biopsy with:
  • Iron stain (to assess for ring sideroblasts)
  • Cytogenetics
  • Molecular studies (particularly for JAK2, CALR, MPL mutations)
  • Reticulin stain (to assess for fibrosis)

Step 2: Additional Testing

• Peripheral blood smear review for additional dysplastic features
• Serum erythropoietin level
• Vitamin B12, folate, and ferritin levels
• Liver function tests
• Renal function tests

Differential Diagnosis

1. Myeloproliferative Neoplasm (MPN):

   • Essential thrombocythemia (ET)
   • Primary myelofibrosis (PMF), early phase
   • Polycythemia vera (PV)

2. Myelodysplastic Syndrome (MDS):

   • Particularly MDS with ring sideroblasts and thrombocytosis (RARS-T) 2

3. Mixed MDS/MPN:

   • Refractory anemia with ring sideroblasts and marked thrombocytosis (RARS-T)
   • Atypical chronic myeloid leukemia

4. Secondary (Reactive) Thrombocytosis:

   • Less likely given the presence of tear drop cells and anemia

Management Approach

Immediate Management

• Complete diagnostic workup as outlined above
• Avoid aspirin or other antiplatelet agents until diagnosis is confirmed
• Monitor for bleeding or thrombotic complications

Post-Diagnostic Management

Based on bone marrow findings:

1. If MPN is confirmed:

   • Cytoreductive therapy may be needed if platelet count remains extremely high
   • Hydroxyurea may be considered in severe cases with thrombotic risk
   • Regular monitoring of blood counts

2. If MDS is confirmed:

   • Management based on risk stratification
   • Supportive care with transfusions as needed
   • Consider erythropoiesis-stimulating agents for anemia

3. If Mixed MDS/MPN is confirmed:

   • Treatment approach depends on dominant features
   • May require both supportive care and cytoreductive therapy

Important Considerations

• Pediatric MDS/MPN is rare but must be considered in a child with these findings
• Bone marrow examination is essential and should not be delayed 1
• Cytogenetic abnormalities may provide crucial diagnostic and prognostic information
• Tear drop cells in combination with thrombocytosis and anemia strongly suggest a primary bone marrow disorder rather than a reactive process 1

Follow-up Plan

• Weekly CBC monitoring initially
• Bone marrow reassessment based on initial findings (3-6 months)
• Long-term monitoring for disease progression
• Referral to pediatric hematology-oncology center with expertise in rare pediatric myeloid disorders

The presence of tear drop cells on peripheral smear is particularly concerning as it is listed as a sign of dysplasia in MDS according to WHO classification 1, and when combined with thrombocytosis and anemia, warrants thorough bone marrow evaluation to establish a definitive diagnosis and guide appropriate management.