Can a Myeloproliferative Neoplasm (MPN) present with anemia, leukocytosis, hypoalbuminemia, normal spleen size, hyperbilirubinemia, and a suspicious lung mass?

Myeloproliferative Neoplasm Presentation with Atypical Features

A myeloproliferative neoplasm (MPN) can indeed present with anemia, leukocytosis, hypoalbuminemia, normal spleen size, elevated bilirubin, and a suspicious lung mass, though this constellation of findings is atypical and suggests either an advanced disease state or concurrent pathology.

Clinical Presentation of MPNs

MPNs typically present with variable laboratory and clinical findings:

• Blood Count Abnormalities:

  • Anemia is common in primary myelofibrosis (PMF) but less typical in early polycythemia vera (PV) or essential thrombocythemia (ET) 1
  • Leukocytosis is frequently seen across MPN subtypes 1

• Spleen Size:

  • Splenomegaly is a hallmark feature of MPNs, particularly in PMF 1
  • Normal spleen size is unusual but possible in early disease

• Liver Function Tests:

  • Hypoalbuminemia suggests advanced disease or concurrent pathology
  • Elevated bilirubin may reflect extramedullary hematopoiesis or hepatic involvement 1

Diagnostic Approach for This Presentation

The combination of findings requires a systematic workup:

1. Complete Blood Count with Differential:

   • Assess degree of anemia and leukocytosis
   • Evaluate for presence of immature myeloid cells in peripheral blood 1

2. Molecular Testing:

   • JAK2, CALR, and MPL mutation analysis
   • BCR-ABL1 testing to exclude CML 1

3. Bone Marrow Examination:

   • Aspirate and biopsy with trichrome and reticulin stain
   • Cytogenetics and FISH analysis 1

4. Evaluation of Lung Mass:

   • CT-guided biopsy to determine if this represents:
     • Extramedullary hematopoiesis (EMH) - can occur in lungs 1
     • Secondary malignancy
     • Unrelated pathology

Interpretation of Findings

The combination of findings suggests several possibilities:

1. Primary Myelofibrosis with Extramedullary Hematopoiesis:

   • Anemia and leukocytosis are consistent with PMF 1
   • The lung mass could represent EMH, which can occur in thoracic sites 1
   • Normal spleen size is unusual but possible in early disease

2. MPN with Concurrent Malignancy:

   • The lung mass may represent a separate primary lung cancer
   • Hypoalbuminemia and hyperbilirubinemia could reflect paraneoplastic effects

3. MPN with Transformation:

   • Progression to blast phase with extramedullary disease
   • Elevated bilirubin and hypoalbuminemia may reflect advanced disease 1

Management Considerations

The management approach should focus on:

1. Confirming MPN Diagnosis:

   • Molecular and morphologic criteria per WHO classification 1

2. Investigating the Lung Mass:

   • Biopsy to differentiate between EMH and malignancy
   • If EMH is confirmed, low-dose radiation therapy (0.1-1 Gy) is effective 1

3. Addressing Anemia:

   • Treatment indicated for hemoglobin <10 g/dL 1
   • Options include corticosteroids, androgens, erythropoiesis-stimulating agents, or immunomodulators 1

4. Managing Leukocytosis:

   • Cytoreductive therapy with hydroxyurea if symptomatic 1

Important Caveats

• Normal Spleen Size: While unusual in advanced MPN, normal spleen size does not exclude the diagnosis
• Lung Mass: Requires tissue diagnosis as this could represent EMH, a second malignancy, or transformation
• Hypoalbuminemia: Not a typical feature of uncomplicated MPN and suggests advanced disease or concurrent pathology
• Elevated Bilirubin: May reflect hepatic involvement by the MPN or concurrent liver pathology

The presence of these atypical features warrants a comprehensive evaluation to determine if they represent manifestations of the MPN itself or concurrent conditions that require separate management.