What is the recommended approach for diagnosing lymphoma?

Recommended Approach for Diagnosing Lymphoma

The gold standard for diagnosing lymphoma is an excisional or incisional lymph node biopsy, as fine-needle aspiration is inadequate for initial diagnosis. 1, 2

Initial Diagnostic Evaluation

• Diagnosis should always be based on a surgical specimen/excisional lymph node biopsy providing adequate tissue for morphology, immunohistochemistry, flow cytometry, and molecular studies 1, 2
• Core needle biopsies should only be performed when excisional biopsy is not possible (e.g., retroperitoneal nodes) or to document relapse 1, 2
• Fine-needle aspirations are inappropriate for reliable diagnosis and should be avoided 1, 2
• When possible, additional tissue should be stored fresh frozen to allow for future molecular analyses 1
• The histological report should follow the World Health Organization classification 1, 2

Clinical Evaluation

• Comprehensive history should document:

  • Age and sex 1
  • Presence of B symptoms (fever >38.3°C, drenching night sweats, unexplained weight loss >10% over 6 months) 1, 3
  • Fatigue, pruritus, and alcohol-induced pain (particularly for Hodgkin lymphoma) 1
  • History of prior malignancy 1

• Physical examination should include:

  • Measurement of all accessible lymph node groups 1, 3
  • Assessment of spleen and liver size in centimeters below costal margins 1

Laboratory Studies

• Complete blood count with differential 1, 2, 3
• Comprehensive chemistry panel including:
  • LDH and uric acid (tumor burden markers) 1, 2, 3
  • Liver and kidney function tests 2, 3
• Mandatory screening for HIV, hepatitis B, and hepatitis C 1, 2, 3
• Protein electrophoresis (recommended for B-cell lymphomas) 1

Imaging Studies

• PET-CT is the standard for FDG-avid lymphomas (Hodgkin lymphoma, aggressive NHL, many indolent NHLs) 1, 2, 4
• CT scan of neck, chest, abdomen, and pelvis with contrast is required if PET-CT is not available 1, 2, 4
• PET-CT improves staging accuracy compared to CT alone, particularly important before radiation therapy 1

Bone Marrow Assessment

• Bone marrow aspirate and biopsy should be performed 1
• PET-CT may be adequate for determining bone marrow involvement in Hodgkin lymphoma, but biopsy confirmation may still be needed for other lymphoma types 1, 2, 4

Additional Evaluations for Specific Presentations

• For suspected CNS involvement:
  • Lumbar puncture for cerebrospinal fluid assessment (cytology, flow cytometry) 1, 2
  • MRI of the brain 1, 2
• For suspected gastrointestinal involvement:
  • Endoscopy with biopsy 2

Staging and Risk Assessment

• Staging should follow the Ann Arbor/Lugano classification system 1, 2
• For prognostic purposes, the International Prognostic Index (IPI) should be established for aggressive lymphomas 1
• For follicular lymphoma, the Follicular Lymphoma International Prognostic Index (FLIPI) should be determined 1, 2

Common Pitfalls to Avoid

• Relying on fine-needle aspiration for initial diagnosis (inadequate tissue) 1, 2
• Performing core biopsies when excisional biopsies are feasible 1
• Failing to store additional tissue for molecular studies 1
• Initiating treatment before complete staging evaluation 1, 2
• Overlooking the need for hepatitis and HIV screening which can impact treatment decisions 1, 3

By following this systematic approach to lymphoma diagnosis, clinicians can ensure accurate classification and staging, which are essential for determining appropriate treatment strategies and improving patient outcomes.