What are the possible causes of splenomegaly in a 12-year-old with a negative Epstein-Barr virus test?

Causes of Splenomegaly in a 12-Year-Old with Negative EBV Test

In a 12-year-old with splenomegaly and negative EBV testing, you must systematically evaluate for hematologic malignancies (leukemia, lymphoma), other infections (CMV, HIV, malaria, toxoplasmosis), chronic liver disease with portal hypertension, autoimmune conditions (particularly SLE), and storage disorders like Gaucher disease. 1, 2, 3

Critical Initial Diagnostic Steps

Immediate Laboratory Workup

• Complete blood count with differential to distinguish isolated splenomegaly from pancytopenia, which strongly suggests bone marrow infiltration, myelodysplastic syndrome, or acute leukemia 1, 2
• Peripheral blood smear review by a hematologist to identify schistocytes, giant platelets, leukocyte abnormalities, or malignant cells 1
• HIV and hepatitis C serology regardless of risk factors, as both commonly cause splenomegaly with thrombocytopenia and may precede other symptoms by years 1

Essential Imaging

• Abdominal ultrasound or CT to measure spleen size objectively (age-dependent reference values are critical in children), assess liver architecture for cirrhosis or portal hypertension, and identify focal splenic lesions 1, 2

Differential Diagnosis by Category

Hematologic Malignancies (High Priority)

• Acute leukemia, lymphoma, or myelodysplastic syndrome must be excluded urgently if pancytopenia is present 1
• Bone marrow aspiration and biopsy with flow cytometry and cytogenetics is mandatory when pancytopenia exists 1
• Peripheral blood flow cytometry can diagnose lymphoproliferative disorders including chronic lymphocytic leukemia or splenic marginal zone lymphoma 1
• EBV-associated lymphoproliferative disorders can occur even with negative standard EBV serology; consider EBV viral load by quantitative PCR and EBER in situ hybridization if tissue is obtained 4, 5

Important caveat: While EBV is typically positive in NK/T-cell lymphomas and most post-transplant lymphoproliferative disorders, a negative EBV test does not completely exclude these diagnoses in rare cases 4. However, NCCN guidelines state that EBV infection is "always present" in extranodal NK/T-cell lymphoma, and a negative EBER-ISH should prompt review for alternative diagnoses 4.

Infectious Causes Beyond EBV

• Cytomegalovirus (CMV) causes mononucleosis-like illness with splenomegaly, particularly in children under 10 years where heterophile antibodies are frequently negative 4
• Malaria requires urgent thick and thin blood films if any travel to endemic regions occurred within the past year; Plasmodium falciparum can cause rapid deterioration and death 1
• Toxoplasma gondii produces mononucleosis-like syndrome with splenomegaly 4
• HIV should be tested universally, as it commonly presents with splenomegaly before other manifestations 1
• Adenovirus can mimic EBV mononucleosis 4

Autoimmune Disorders

• Systemic lupus erythematosus (SLE) commonly manifests with fever, cytopenias, and splenomegaly in young patients 1
• Test for antinuclear antibodies, anti-dsDNA, complement C3/C4, and antiphospholipid antibodies when SLE is suspected 1

Storage Disorders

• Gaucher disease should be considered when splenomegaly is disproportionate or massive, even in previously asymptomatic patients 6
• Bone marrow biopsy may reveal Gaucher cells; confirm with beta-glucosidase enzyme activity assay 6

Hepatic and Vascular Causes

• Chronic liver disease with portal hypertension causes congestive splenomegaly 1, 3
• Assess liver function tests and look for signs of cirrhosis on imaging 1

Algorithmic Approach

If Pancytopenia Present:

1. Immediate bone marrow aspiration and biopsy with flow cytometry and cytogenetics to exclude acute leukemia, myelodysplastic syndrome, or lymphoma infiltration 1
2. Do not delay this evaluation—hematologic malignancies require urgent diagnosis 1

If Isolated Splenomegaly or Thrombocytopenia:

1. Complete infectious workup: CMV serology, HIV, hepatitis C, malaria films (if travel history), toxoplasma serology 4, 1
2. Autoimmune screening: ANA, anti-dsDNA, complement levels if clinical features suggest SLE 1
3. Peripheral blood flow cytometry to screen for lymphoproliferative disorders 1
4. Consider bone marrow examination if no diagnosis established, particularly if age >10 years or concerning features present 1

If Massive Splenomegaly:

1. Strongly consider Gaucher disease and other storage disorders 6
2. Evaluate for EBV-associated lymphoproliferative disorder with EBV viral load by PCR and tissue biopsy if accessible 5

Critical Pitfalls to Avoid

• Do not assume negative EBV serology excludes all EBV-related disease: False-negative heterophile tests occur in approximately 10% of patients and are especially common in children under 10 years 4
• Do not start empiric corticosteroids before excluding infectious etiologies; steroids can precipitate fulminant sepsis in undiagnosed malaria or disseminated infections 1
• Do not overlook travel history: Malaria and schistosomiasis are common causes of splenomegaly in tropical regions, affecting up to 80% of populations in endemic areas 3
• Do not delay malaria testing when travel history is positive; untreated malaria can progress to multi-organ failure within 24-48 hours 1

When to Pursue Tissue Diagnosis

• Lymph node or splenic tissue biopsy with EBER in situ hybridization and immunohistochemistry should be pursued if lymphoproliferative disorder remains suspected despite negative standard EBV testing 4, 5
• This is particularly important in sub-Saharan African contexts where EBV-associated lymphoproliferative disorders may present atypically 5