Lymphoma Diagnosis in Children

Diagnostic Approach

The National Comprehensive Cancer Network (NCCN) recommends excisional or incisional lymph node biopsy as the definitive diagnostic approach for pediatric aggressive B-cell lymphomas, with fresh tissue sent in saline to ensure viability 1
Lymph node biopsy provides the tissue architecture and comprehensive immunophenotyping required for accurate lymphoma classification, which neither CBC nor bone marrow biopsy can reliably deliver 1
Morphologic examination, immunohistochemistry, immunophenotyping, and cytogenetics are all essential to establish a definitive diagnosis of Burkitt lymphoma or diffuse large B-cell lymphoma 1

CBC with differential and platelets is listed as "essential" in the workup algorithm, but only for staging and baseline assessment—not diagnosis 5, 3
Bone marrow biopsy is performed after lymphoma diagnosis is established by lymph node biopsy, and is used to determine if there is stage IV disease (>5% lymphoma cells in marrow) 1, 4
Bone marrow involvement affects risk stratification and treatment intensity, but the primary diagnosis must come from lymph node tissue 4

Step 1: Obtain excisional or incisional biopsy of the most accessible enlarged lymph node 1, 2
Step 2: Send fresh tissue in saline for touch preparation, morphologic review, immunohistochemistry, flow cytometry, and cytogenetics 1, 3, 4
Step 3: Once diagnosis is confirmed, proceed with staging workup including CBC, bone marrow biopsy, lumbar puncture, and imaging 1, 4

Never rely on CBC alone to diagnose lymphoma in a child with lymphadenopathy—this will miss the diagnosis in most cases 1, 2
Do not perform bone marrow biopsy first—the primary tissue diagnosis must come from the lymph node itself 1, 4
Avoid fine needle aspiration as the sole diagnostic procedure in suspected new lymphoma, as it lacks tissue architecture needed for classification 3, 2