What tests should be ordered for a patient presenting with left anterior lymph node swelling?

Diagnostic Workup for Left Anterior Lymph Node Swelling

For a patient presenting with left anterior lymph node swelling, obtain an excisional lymph node biopsy as the primary diagnostic procedure, accompanied by complete blood count with differential, lactate dehydrogenase, comprehensive metabolic panel, and contrast-enhanced CT imaging of the chest, abdomen, and pelvis. 1

Initial Tissue Diagnosis

Excisional lymph node biopsy is the gold standard and should generally be performed to establish an accurate pathologic diagnosis, as this provides adequate tissue architecture for histologic evaluation and immunophenotyping. 1

• Core needle biopsy may be adequate if diagnostic, but is less preferred than excisional biopsy for initial diagnosis. 1
• Fine-needle aspiration (FNA) alone is insufficient for initial diagnosis except in unusual circumstances when combined with immunohistochemistry and judged diagnostic by an expert hematopathologist. 1
• The diagnostic accuracy of FNA improves significantly when combined with flow cytometry and immunohistochemistry, but tissue architecture is still compromised. 1, 2

Critical Pitfall to Avoid

FNA has a high false-negative rate for low-grade lymphomas that mimic reactive lymphoid populations, and can miss entities like nodular lymphocyte predominant Hodgkin lymphoma due to paucity of lesional cells. 2 Do not rely on FNA alone for initial diagnosis—proceed directly to excisional biopsy. 1

Essential Laboratory Tests

Core Blood Work

• Complete blood count (CBC) with differential and platelets to evaluate for bone marrow involvement, cytopenias, and abnormal lymphocyte populations. 1, 3
• Serum lactate dehydrogenase (LDH) as a critical prognostic marker and component of the International Prognostic Index. 1, 3
• Comprehensive metabolic panel including liver and renal function tests to assess organ involvement. 1, 3
• Erythrocyte sedimentation rate (ESR) for prognostic stratification. 1, 4

Infectious Disease Screening

• Hepatitis B and C testing is required before initiating treatment, particularly anti-CD20 therapy, due to reactivation risk. 1, 3
• HIV testing should be encouraged for patients with risk factors or unusual disease presentations. 1, 4
• Consider tuberculosis testing if lymphadenopathy persists beyond four weeks or systemic symptoms are present. 4

Additional Prognostic Markers

• β2-microglobulin as an important prognostic marker, especially if follicular lymphoma is suspected. 3
• Uric acid as part of tumor lysis syndrome panel before initiating treatment. 3

Imaging Studies

Required Imaging

PET/CT scan from skull base to mid-thigh is essential for initial staging and should be obtained no longer than 1 month before starting therapy. 1

• Contrast-enhanced diagnostic CT of the neck (if involved), chest, abdomen, and pelvis is recommended. 1
• A separate diagnostic CT is not needed if it was part of an integrated PET/CT scan. 1
• Chest radiograph (posterior-anterior and lateral) is encouraged in selected cases, particularly if large mediastinal mass is suspected. 1

Imaging Interpretation

The NCCN Guidelines support the American College of Radiology and Society of Nuclear Medicine recommendations for PET/CT interpretation using standardized criteria. 1

Immunophenotyping and Pathologic Evaluation

Once tissue is obtained, the following immunostaining panel is essential:

For Classical Hodgkin Lymphoma Suspicion

• CD3, CD15, CD20, CD30, CD45, CD79a, and PAX5 are recommended. 1
• Reed-Sternberg cells express CD30 in all patients and CD15 in most; they are usually negative for CD3 and CD45. 1

For Non-Hodgkin Lymphoma Suspicion

• Pan-B cell markers (CD19, CD20, CD22) and pan-T cell markers (CD3, CD5) should be included in the initial panel. 1, 3
• Flow cytometry is essential for determining lymphoma subtype and clonality. 1, 3

Bone Marrow Evaluation

Bone marrow biopsy is NOT routinely required in patients with newly diagnosed Hodgkin lymphoma undergoing pretreatment staging with PET/CT if the PET scan is negative or displays homogeneous bone marrow uptake. 1

• Bone marrow may be assumed involved if PET scan displays multifocal (≥3) skeletal lesions. 1
• Perform bone marrow biopsy if cytopenias are present despite negative PET findings. 1
• For non-Hodgkin lymphoma, bone marrow biopsy is an essential component of staging in most cases. 3

Additional Considerations Based on Clinical Context

If Systemic Symptoms Present

Document B symptoms including unexplained fevers >38°C, drenching night sweats, or weight loss >10% within 6 months. 1

If Cardiac Risk Factors or Anthracycline Therapy Planned

• Ejection fraction evaluation (echocardiogram or MUGA scan) is recommended for patients undergoing doxorubicin-based chemotherapy. 1, 3

If Bleomycin Therapy Planned

• Pulmonary function tests, including diffusing capacity of lungs for carbon monoxide (DLCO), are recommended. 1

If Splenic Radiation Contemplated

• Haemophilus influenzae, pneumococcal, and meningococcal vaccines are recommended. 1

Timeline for Diagnostic Workup

If lymphadenopathy persists beyond four weeks or is accompanied by systemic symptoms (fever, night sweats, weight loss), proceed immediately with imaging and laboratory studies outlined above. 4, 5

• Do not wait beyond one month for persistent lymphadenopathy—invasive diagnostic procedures are indicated to rule out malignancy. 5
• Lymph nodes larger than 2 cm, hard, or matted/fused to surrounding structures indicate higher likelihood of malignancy or granulomatous disease and require expedited workup. 4

Critical Pitfall: Avoid Corticosteroids

Corticosteroids should be avoided before tissue diagnosis because they can mask the histologic diagnosis of lymphoma or other malignancy. 4