What is the next step in management for a patient with suspected lymphoma, presenting with enlarged lymph nodes, and complaining of middle back pain on the left side after palpation?

Management of Suspected Lymphoma with Enlarged Lymph Nodes and Back Pain

Obtain an excisional lymph node biopsy immediately to establish a definitive diagnosis, as this is the gold standard and mandatory first step before any treatment decisions can be made. 1, 2, 3

Immediate Diagnostic Priority

The presence of enlarged lymph nodes with suspicion of lymphoma requires tissue diagnosis before proceeding with any staging or treatment. The back pain you're noting may represent:

• Bone involvement from lymphoma
• Retroperitoneal lymphadenopathy causing referred pain
• Unrelated musculoskeletal pain

However, diagnosis must precede staging investigations. 1, 2

Biopsy Approach

• Surgical excisional biopsy of the enlarged lymph node is mandatory and provides adequate tissue for both formalin-fixed and fresh frozen samples needed for complete histopathological examination, immunohistochemistry (including CD20), and molecular characterization 1, 2, 3

• Core needle biopsy should only be used if surgical approach is impractical or would entail excessive risk 1, 3

• Fine needle aspiration is inadequate and should not be used as the sole basis for lymphoma diagnosis 1, 2, 3

• The specimen must be processed by an experienced haematopathology laboratory with expertise in morphological interpretation and facilities for the full range of phenotypic and molecular investigations 1

Concurrent Initial Workup (While Arranging Biopsy)

While scheduling the biopsy, obtain baseline studies that will be needed regardless:

• Complete blood count with differential 1, 4
• Comprehensive metabolic panel including LDH and uric acid (LDH is a prognostic marker and component of IPI scoring) 1, 4
• Screening for HIV, hepatitis B, and hepatitis C (mandatory before any rituximab-containing therapy) 1, 4
• Protein electrophoresis 1

Staging After Diagnosis is Confirmed

Only after histological diagnosis is established, proceed with complete staging:

• FDG-PET/CT scan is the gold standard for staging and should be performed in all patients with confirmed DLBCL 1

• Bone marrow aspirate and biopsy may be avoided when PET/CT demonstrates bone or marrow involvement indicating advanced-stage disease, but is appropriate when PET is negative and results would change prognosis or treatment 1, 4

• Cardiac function assessment (LVEF) before treatment with anthracycline-based regimens 1, 4

• Ann Arbor staging classification and International Prognostic Index (IPI) calculation for prognostic stratification 1, 3

Addressing the Back Pain

If the back pain is severe, progressive, or associated with neurological symptoms:

• Consider MRI of the spine to evaluate for epidural extension or vertebral involvement, as this would constitute an oncologic emergency requiring urgent intervention 1

• Diagnostic lumbar puncture should be considered in high-risk patients (those with testicular, paranasal sinus, or bone marrow involvement, or elevated LDH with multiple extranodal sites) 1

Critical Pitfalls to Avoid

• Do not delay biopsy to obtain imaging first - tissue diagnosis is the priority 1, 2, 3

• Do not rely on imaging characteristics alone to diagnose lymphoma, as many benign conditions mimic lymphoma radiographically 5

• Do not accept inadequate tissue sampling - if initial core biopsy is non-diagnostic, proceed to excisional biopsy 1, 2

• In cases with high tumor burden, be prepared to prevent tumor lysis syndrome with hydration and consideration of prednisone prephase treatment once diagnosis is confirmed 1