What are the typical lab findings for a patient suspected of having Burkitt lymphoma?

Burkitt Lymphoma Laboratory Findings

Burkitt lymphoma presents with characteristic laboratory abnormalities including markedly elevated serum lactate dehydrogenase (LDH), often >500 U/L, elevated uric acid levels indicating high tumor burden, and frequently demonstrates leukemic involvement with circulating malignant cells on peripheral blood flow cytometry. 1, 2

Essential Laboratory Tests

Hematologic Studies

• Complete blood count (CBC) with differential and platelets is essential to evaluate for leukemic phase (present in approximately 40% of cases), cytopenias from bone marrow involvement, and abnormal lymphocyte populations 1, 3
• Peripheral blood flow cytometry should be performed to detect circulating malignant cells, with immunophenotyping showing CD20+, CD10+, surface immunoglobulin positive, TdT negative, and BCL2 negative pattern 1
• Bone marrow biopsy with aspirate is mandatory for staging, as bone marrow involvement is a poor prognostic indicator and excludes patients from low-risk categories 1, 2

Biochemical Markers

• Serum LDH is the single most important prognostic laboratory marker, with levels >500-700 U/L correlating with extensive tumor burden and predicting worse outcomes 1, 2, 3
• Uric acid levels must be measured as part of tumor lysis syndrome assessment, given the extremely high proliferation rate (Ki-67 approaching 100%) and risk of spontaneous tumor lysis 1
• Comprehensive metabolic panel including electrolytes (particularly potassium, calcium, phosphate), renal function, and liver function is essential to monitor for tumor lysis syndrome and organ involvement 1, 4

Infectious Disease Screening

• HIV testing is mandatory, as Burkitt lymphoma is an AIDS-defining malignancy and treatment approach may differ in HIV-positive patients 1
• Hepatitis B surface antigen and core antibody testing is required before rituximab-containing regimens due to reactivation risk 1, 4
• Hepatitis C testing should be performed in high-risk patients 4

Specialized Diagnostic Studies

Immunophenotyping and Molecular Testing

• Cytogenetics or FISH for t(8;14) or variant translocations involving MYC is diagnostic and required to confirm Burkitt lymphoma 1
• MYC, IgH, BCL2, and BCL6 rearrangement testing by FISH helps distinguish Burkitt lymphoma from "double-hit" or "triple-hit" diffuse large B-cell lymphomas 1
• Ki-67 proliferation index approaches 100% in Burkitt lymphoma, distinguishing it from other aggressive lymphomas 1

Central Nervous System Evaluation

• Lumbar puncture with CSF flow cytometry is essential in all patients, as CNS involvement occurs frequently and dramatically worsens prognosis 1
• Baseline CSF analysis plus one dose of intrathecal methotrexate should be performed at diagnosis 1

Prognostic Laboratory Parameters

High-Risk Features

• LDH >500-700 U/L identifies patients with extensive disease who require intensive therapy and have higher relapse rates 2, 3
• Bone marrow involvement on biopsy is associated with poor outcomes, with no long-term survivors in early series 2
• Elevated white blood cell count with leukemic presentation (40.7% of cases) indicates high tumor burden 3
• Beta-2-microglobulin elevation may provide additional prognostic information, though less established than LDH 4

Critical Pitfalls to Avoid

Tumor Lysis Syndrome Monitoring

• Hyperkalemia is the most dangerous acute complication, causing sudden death within 48 hours of chemotherapy initiation in patients with large tumor masses 2
• Serial monitoring of potassium, phosphate, calcium, uric acid, and creatinine must begin immediately upon diagnosis, before treatment initiation 1, 2
• Patients with elevated LDH and large tumor burden require aggressive hydration and tumor lysis prophylaxis before any chemotherapy 2

Diagnostic Accuracy

• Core needle biopsy or FNA alone is insufficient for initial diagnosis; excisional lymph node biopsy with adequate tissue for immunohistochemistry, flow cytometry, and molecular studies is required 1
• Distinguishing Burkitt lymphoma from diffuse large B-cell lymphoma is critical, as treatment regimens differ substantially; CHOP chemotherapy is inadequate for Burkitt lymphoma 1

Additional Considerations

• Protein electrophoresis may be useful to evaluate for paraproteinemia, though less commonly abnormal than in other B-cell lymphomas 1, 4
• Cardiac function assessment with MUGA scan or echocardiogram is required before anthracycline-based intensive regimens 1, 4
• Pregnancy testing in women of childbearing age is mandatory before initiating chemotherapy 1