What is the diagnostic workup for a patient with enlarged abdominal lymph nodes?

Diagnostic Workup for Enlarged Abdominal Lymph Nodes

Begin with contrast-enhanced CT scan of the chest, abdomen, and pelvis, followed by tissue diagnosis via excisional lymph node biopsy or core needle biopsy when lymphoma is suspected. 1, 2

Initial Clinical Assessment

Document specific constitutional symptoms and perform targeted physical examination:

• Record presence of B symptoms: fever >38°C, drenching night sweats, unexplained weight loss >10% over 6 months 1, 2
• Document additional symptoms: fatigue, pruritus, alcohol-induced pain 1
• Measure all accessible peripheral lymph node groups to identify alternative biopsy sites 2
• Assess liver and spleen size on physical examination 1, 2
• Evaluate performance status 1

Essential Laboratory Studies

Order the following baseline laboratory panel:

• Complete blood count with differential to assess for cytopenias or leukocytosis 1, 2
• Comprehensive metabolic panel including liver enzymes, alkaline phosphatase, and albumin 1
• Lactate dehydrogenase (LDH) as a marker of tumor burden and prognostic indicator 1, 2
• Uric acid level (especially important if high tumor burden present to assess tumor lysis risk) 1
• Hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (HBcAb) - mandatory before any treatment 1
• Hepatitis C and HIV screening 1, 2
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) 1
• Protein electrophoresis for suspected B-cell processes 1

Imaging Studies

CT imaging is the mandatory initial radiologic study:

• Contrast-enhanced CT scan of neck, chest, abdomen, and pelvis with oral and intravenous contrast (unless contraindicated by renal insufficiency) 1, 2
• Chest X-ray as baseline 1
• PET-CT should be obtained for staging if lymphoma is confirmed, though typically arranged after tissue diagnosis 1, 2

CT characteristics that suggest lymphoma include: 3

• Solitary mass type: single round uniform-density enlarged nodes or multiple nodes fusing into lobular mass
• Multiple-nodular type: multiple round enlarged nodes with uniform density and clear margins
• Diffuse type with "cobblestone signs"
• Vessel-embedded signs (mesenteric vessels, renal vessels, aorta, or IVC)

Tissue Diagnosis - The Critical Step

Excisional or incisional lymph node biopsy is the gold standard and should almost always be performed: 1, 2

• Provides adequate tissue for fresh frozen and formalin-fixed samples 1
• Allows comprehensive pathologic evaluation including morphology, immunohistochemistry, flow cytometry, and molecular studies 2
• Immediate processing by experienced pathology institute is essential 1

Core needle biopsy or fine-needle aspiration may be considered only in specific circumstances: 1, 4, 5

• Patients requiring emergency treatment 1
• Patients not suitable for curative therapy 1
• Nodes in difficult-to-access locations (retroperitoneal, periportal) 2, 4, 5
• When peripheral nodes are not accessible 4

For abdominal nodes specifically: 4, 5

• Laparoscopic biopsy provides safe and effective tissue acquisition when nodes are small, in locations unsuitable for image-guided biopsy, or when adequate tissue cannot be obtained percutaneously 4
• EUS-guided fine-needle aspiration is recommended for periportal lymph nodes, as 18.8% harbor malignancy even without identifiable pancreatobiliary or hepatic cancer 5

Bone Marrow Evaluation

Bone marrow biopsy decisions depend on imaging availability:

• If PET-CT is performed, bone marrow biopsy is no longer indicated due to high sensitivity of PET-CT for marrow involvement 1
• If PET-CT is not available, bone marrow aspirate and biopsy are essential 1
• May be deferred in certain circumstances when treatment is not immediately considered 1

Additional Considerations for High-Risk Features

Perform lumbar puncture with prophylactic intrathecal chemotherapy in high-risk patients: 1

• More than two adverse parameters by International Prognostic Index (IPI)
• Bone marrow involvement
• Testicular involvement
• Spinal involvement
• Base of skull involvement

Critical Pitfalls to Avoid

Do not assume benignity based solely on imaging: While enlarged abdominal lymph nodes can be benign (particularly in cirrhosis where 50% have enlarged nodes from hyperplasia) 6, tissue diagnosis is essential when lymphoma is suspected 5

Do not accept inadequate tissue: Fine-needle aspiration alone may be insufficient for complete immunophenotyping and molecular characterization required for lymphoma subtyping 1, 2

Do not delay hepatitis B screening: Hepatitis B reactivation can occur with chemotherapy and anti-CD20 therapy, making pre-treatment screening mandatory 1

Disposition and Consultation

Immediate hematology/oncology consultation is necessary for all patients with strong suspicion of lymphoma 2

Admission criteria include: 2

• Significant B symptoms affecting functional status
• Bulky disease causing airway compromise or organ dysfunction
• Tumor lysis syndrome
• Superior vena cava syndrome

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