What does an enlarged spleen with a volume of 598 mL in a 17-year-old indicate?

Enlarged Spleen in a 17-Year-Old: Diagnostic Approach and Management

An enlarged spleen with a volume of 598 mL in a 17-year-old requires prompt evaluation for underlying hematologic disorders, particularly leukemia, lymphoma, or immunodeficiency, as these conditions significantly impact morbidity and mortality.

Understanding Splenomegaly in Adolescents

Splenomegaly in adolescents is almost always a sign of an underlying systemic condition that requires investigation. The normal spleen volume varies by age, but 598 mL represents significant enlargement in a 17-year-old.

Common Causes of Adolescent Splenomegaly

• Hematologic malignancies
  • Leukemia (particularly chronic myeloid leukemia)
  • Lymphoma
• Infections
  • Infectious mononucleosis
  • Bacterial or fungal infections
• Immunologic disorders
  • Common Variable Immunodeficiency (CVID)
• Liver disease with portal hypertension
• Hemolytic anemias

Diagnostic Approach

Initial Laboratory Workup

1. Complete blood count with differential

   • Look for cytopenias, abnormal cells, or increased white blood cell count 1
   • Assess for "pathological shift to left" in granulocytes (suggestive of CML) 2

2. Liver function tests

   • To evaluate for hepatic causes of splenomegaly 1

3. Additional blood tests

   • Immunoglobulin levels (to assess for CVID) 1
   • Peripheral blood smear
   • Epstein-Barr virus serology (if infectious mononucleosis suspected)

Further Imaging

1. Abdominal CT or MRI

   • For better characterization of splenic architecture
   • To assess for focal lesions and lymphadenopathy 1

2. Consider PET-CT

   • If lymphoma is suspected 1

Potential Need for Tissue Diagnosis

1. Bone marrow aspiration/biopsy

   • If blood tests suggest hematologic malignancy

2. Lymph node biopsy

   • If lymphadenopathy is present

Clinical Correlation

The International Registry of Childhood CML indicates that children and adolescents with chronic myeloid leukemia present with a higher frequency of splenomegaly and larger spleen size compared to adults 2. This is particularly important as CML is a significant cause of splenomegaly in adolescents.

Symptoms that may accompany splenomegaly in conditions like CML include:

• Fatigue (46% of patients)
• Weight loss (25%)
• Fever (23%)
• Abdominal pain 2

Management Considerations

Management depends on the underlying cause:

1. For hematologic malignancies:

   • If CML is diagnosed, tyrosine kinase inhibitors (TKIs) are the mainstay of treatment
   • Recent evidence suggests bosutinib may have a growth-sparing effect in adolescents 2

2. For immunodeficiencies like CVID:

   • Immunoglobulin replacement therapy 1

3. For infectious causes:

   • Targeted antimicrobial therapy

Complications to Monitor

1. Risk of splenic rupture

   • Advise against contact sports 3
   • Monitor for abdominal pain, especially left upper quadrant

2. Cytopenias due to hypersplenism

   • Regular blood count monitoring 1

3. Potential vascular complications

   • Splenic infarction
   • Portal hypertension

Important Caveats

1. Do not dismiss as "normal variant"

   • Splenomegaly in adolescents almost always indicates underlying pathology

2. Consider rare causes in appropriate contexts

   • Travel history (malaria, schistosomiasis)
   • Medication review (drug-induced splenomegaly) 4

3. Serial monitoring is essential

   • Follow spleen size with ultrasound if diagnosis is not immediately apparent 1

The finding of an enlarged spleen requires systematic evaluation to determine the underlying cause, as early diagnosis and treatment of conditions like leukemia or lymphoma can significantly improve outcomes in adolescent patients.