A 36-year-old woman with mild-to-moderate splenomegaly and laboratory findings of leukopenia (WBC 3.12 ×10⁹/L), thrombocytopenia (platelets 103–110 ×10⁹/L), and anemia (hemoglobin 10.1 g/dL): what is the likely impression and recommended management?

Impression: Primary Myelofibrosis (PMF)

This clinical presentation—pancytopenia (anemia, leukopenia, thrombocytopenia) with mild-to-moderate splenomegaly in a 36-year-old woman—is most consistent with a myeloproliferative neoplasm, specifically primary myelofibrosis (PMF) or early-stage myelofibrosis. 1, 2, 3

Diagnostic Workup Required

The following tests must be performed immediately to confirm the diagnosis:

Essential Laboratory Studies

• Peripheral blood smear evaluation by a hematopathologist to assess for leukoerythroblastosis, teardrop cells, and immature myeloid cells 3
• Bone marrow aspirate and biopsy with:
  • Morphologic assessment for megakaryocyte abnormalities (small-to-large megakaryocytes with hyperchromatic, irregularly folded nuclei and dense clustering) 3
  • Reticulin/collagen fibrosis grading 3
  • Cytogenetic analysis (karyotype) 3
  • Flow cytometry 4

Molecular Testing

• JAK2 V617F mutation (present in ~60% of PMF cases) 3
• CALR mutation (present in ~25% of PMF cases) 3
• MPL mutation (present in ~8% of PMF cases) 3
• If all three are negative, test for accompanying mutations: ASXL1, EZH2, TET2, SRSF2, SF3B1 3

Additional Studies

• LDH level (typically elevated in PMF) 1, 3
• Comprehensive metabolic panel 1
• Constitutional symptom assessment: >10% weight loss in 6 months, night sweats, unexplained fever >37.5°C 1

Differential Diagnosis to Exclude

Before confirming PMF, systematically exclude:

1. Secondary causes of splenomegaly with cytopenias:

   • HIV and hepatitis C serology 4
   • Autoimmune disorders (ANA, anti-dsDNA for SLE) 4
   • Chronic liver disease (hepatic function panel, imaging) 4

2. Other hematologic malignancies:

   • Chronic myeloid leukemia (BCR-ABL1 testing—though CML typically presents with leukocytosis, not leukopenia) 5, 6
   • Hairy cell leukemia (flow cytometry for CD103, CD11c, CD25, CD123) 7
   • Myelodysplastic syndromes 4
   • Chronic lymphocytic leukemia 4

3. Hypersplenism from other causes:

   • Portal hypertension/cirrhosis 4
   • Gaucher disease or other storage disorders (in younger patients)
   • IgG4-related disease (though rare) 8

Risk Stratification Once PMF Confirmed

Use the DIPSS-Plus scoring system to determine prognosis and treatment urgency 3:

Risk factors (assign points):

• Age >65 years (1 point) — Not applicable here
• Constitutional symptoms (1 point)
• Hemoglobin <10 g/dL (2 points) — Present (Hgb 10.1 g/dL, borderline)
• WBC count >25 × 10⁹/L (1 point) — Not present
• Circulating blasts ≥1% (1 point) — Requires blood smear
• RBC transfusion need (1 point)
• Platelet count <100 × 10⁹/L (1 point) — Present (103-110)
• Unfavorable karyotype (1 point) — Requires cytogenetics

Risk groups:

• Low risk: 0 points
• Intermediate-1: 1 point
• Intermediate-2: 2-3 points
• High risk: 4-6 points

Management Strategy

If PMF is Confirmed:

For Anemia (Hemoglobin 10.1 g/dL):

First-line options 2, 9:

1. Erythropoiesis-stimulating agents (ESAs) if:

   • Endogenous erythropoietin level <125 mU/mL
   • No significant splenomegaly (mild-moderate may still respond)
   • Not transfusion-dependent
   • Response rate: 23-60% 2
   • Trial for 3 months; discontinue if no response 2

2. Danazol 400-600 mg daily 2, 9:

   • Maintain for at least 6 months
   • Response rate: 35% 2
   • Less toxicity than other androgens

3. Low-dose thalidomide (50 mg/day) + prednisone (15-30 mg/day) 2, 9:

   • Response rate: 23-29%
   • Monitor for toxicity

For Splenomegaly (Mild-to-Moderate):

If symptomatic or progressive 1, 2, 9:

1. JAK inhibitor therapy (first-line for symptomatic splenomegaly) 1, 2, 10:

   • Ruxolitinib dosing based on platelet count 1:

     • Platelets 100-200 × 10⁹/L: 15 mg twice daily (appropriate for this patient with platelets 103-110)
     • Monitor CBC every 2-4 weeks until stable 1
     • Warning: May worsen anemia initially 2

   • Pacritinib: Preferred if platelets <50 × 10⁹/L (not applicable here) 10

   • Momelotinib: Preferred if anemia-dominant disease 10

2. Hydroxyurea (if JAK inhibitors unavailable or contraindicated) 2, 9:

   • Response rate: ~40% for splenomegaly 2
   • Often requires alternative therapy after 1 year 2

For Thrombocytopenia (103-110 × 10⁹/L):

• Observation if asymptomatic and no bleeding 1
• Platelet transfusions only for thrombocytopenic bleeding or platelet count <10 × 10⁹/L 1
• Use leukocyte-reduced blood products if transplant candidate 1

Supportive Care Measures 1:

• Cardiovascular risk factor counseling (smoking cessation, diet, exercise)
• Vaccination: Pneumococcal, meningococcal, H. influenzae (especially if splenectomy considered) 4
• Antibiotic prophylaxis for recurrent infections 1
• Consider G-CSF if recurrent infections with neutropenia 1

Allogeneic Stem Cell Transplantation

Referral to transplant center if 2, 9:

• Intermediate-2 or high-risk disease by DIPSS-Plus
• Age and comorbidities permit
• Only curative option for PMF

Critical Pitfalls to Avoid

1. Do not delay bone marrow biopsy: This is essential for diagnosis and cannot be substituted by peripheral blood tests alone 3

2. Do not start JAK inhibitors without baseline CBC and metabolic panel: Ruxolitinib can worsen anemia and thrombocytopenia 1, 2

3. Do not assume isolated hypersplenism: Splenomegaly with pancytopenia in a young adult requires exclusion of myeloproliferative neoplasms, not just observation 4

4. Do not perform splenectomy as initial management: Reserve for drug-refractory symptomatic splenomegaly with experienced surgical team (perioperative mortality 5-10%) 2, 9

5. Do not use splenic irradiation routinely: Benefit is transient with risk of severe cytopenias 2

Immediate Next Steps

1. Refer to hematology urgently for bone marrow biopsy and molecular testing
2. Order peripheral blood smear review by hematopathologist
3. Check JAK2, CALR, MPL mutations and LDH
4. Screen for HIV, HCV, and autoimmune disorders
5. Assess constitutional symptoms systematically
6. Avoid starting empiric therapy before confirming diagnosis

The combination of pancytopenia with splenomegaly in a young adult mandates aggressive diagnostic workup for myeloproliferative neoplasm, with PMF being the leading diagnosis. 1, 2, 3