A 47-year-old patient presents with swollen lymph nodes in the axilla and groin and neuropathic pain in the hands and head; what is the appropriate evaluation and management?

Urgent Lymphoma Workup with Neurolymphomatosis Evaluation

This patient requires immediate excisional lymph node biopsy and FDG-PET/CT imaging to evaluate for lymphoma with peripheral nervous system involvement (neurolymphomatosis), as the combination of bilateral lymphadenopathy and neuropathic pain is highly concerning for this diagnosis.

Initial Diagnostic Approach

The presentation of swollen axillary and inguinal lymph nodes with neuropathic pain in the hands and head raises immediate concern for lymphoma, specifically neurolymphomatosis (NL)—a rare but serious condition where lymphoma infiltrates the peripheral nervous system 1, 2.

Key Clinical Red Flags Present:

• Bilateral regional lymphadenopathy (axilla and groin) suggesting systemic disease
• Neuropathic pain in asymmetric distribution (hands and head)
• Age 47 years—within typical NL presentation range

The neuropathic symptoms are particularly concerning because NL commonly presents with rapidly deteriorating, asymmetric painful polyneuropathy 1. The involvement of hands suggests peripheral nerve or plexus infiltration, while head pain may indicate cranial nerve involvement—both common NL patterns 1, 2.

Immediate Diagnostic Workup

1. Tissue Diagnosis (Priority #1)

Excisional lymph node biopsy is the gold standard 3. Target the most accessible enlarged node (likely axillary):

• Core-needle biopsy acceptable only if excisional biopsy not feasible 3
• This establishes lymphoma diagnosis and histologic subtype
• 90% of NL cases are B-cell lymphomas 1

2. Imaging Studies (Priority #2)

FDG-PET/CT is mandatory for several critical reasons:

• Standard staging for FDG-avid lymphomas 3
• Diagnostic yield >90% for neurolymphomatosis 1, 2
• More sensitive than MRI for non-mass-forming neural lesions 4
• Identifies extent of nodal and extranodal disease
• Guides targeted nerve biopsy if needed 1

MR neurography should be added if PET-CT shows neural uptake:

• Provides detailed anatomic assessment of nerve involvement 2
• Evaluates brachial plexus, lumbosacral plexus, and cranial nerves 1

3. Laboratory Evaluation

Essential tests include:

• Complete blood count with differential
• Comprehensive metabolic panel
• LDH (prognostic marker)
• HIV testing
• Hepatitis B and C serologies
• Document B symptoms (fever, night sweats, >10% weight loss)—only relevant for Hodgkin lymphoma staging 3

4. Bone Marrow Biopsy

Not routinely needed if PET-CT performed for Hodgkin lymphoma 3. For diffuse large B-cell lymphoma, only required if PET negative and discordant histology would change management 3.

Staging Considerations

Based on the Lugano classification 3:

• Bilateral lymphadenopathy (axilla + groin) = at minimum Stage III (nodes on both sides of diaphragm)
• If neurolymphomatosis confirmed = Stage IV (noncontiguous extralymphatic involvement)

Prognostic Stratification for Neurolymphomatosis

If NL is confirmed, three factors predict better outcomes 1:

1. Primary NL without systemic disease outside nervous system (HR 0.44)
2. Good performance status (ECOG <2, HR 0.30)
3. Rituximab-based treatment (HR 0.46)

Median overall survival for NL is 18 months, but rituximab-based therapy significantly improves outcomes 1.

Critical Pitfalls to Avoid

Diagnostic Delays

• Primary NL has substantial diagnostic delays (median 3 months from symptom onset) 1
• Don't attribute neuropathy to common causes (diabetes, carpal tunnel) without excluding malignancy
• Severe pain, asymmetry, and rapid progression are NOT typical of benign neuropathies 2

Nerve Biopsy Risks

• Carries high risk of irreversible nerve damage 2
• Only pursue if PET/CT and MR neurography are inconclusive
• FDG-PET has >90% diagnostic yield, making invasive nerve biopsy often unnecessary 1

Misdiagnosis Scenarios

• NL can occur with low-grade follicular lymphoma without transformation 4
• Cranial nerve involvement may mimic trigeminal neuralgia 5
• Consider autoimmune causes (SLE can present with lymphadenopathy and neuropathy) 6, but lymphoma must be excluded first

Treatment Implications

Once lymphoma with NL is confirmed:

• Methotrexate or rituximab-based polychemotherapy is standard 1
• Rituximab inclusion is essential for B-cell lymphomas (improves survival) 1
• Treatment response monitored with repeat PET-CT using 5-point scale 3

The urgency stems from NL's rapid progression and the fact that 96% of patients receive tumor-directed therapy, with better outcomes when initiated promptly 1.