What is the initial workup for a patient presenting with inguinal lymphadenopathy?

Initial Workup for Inguinal Lymphadenopathy

The initial workup for a patient presenting with inguinal lymphadenopathy should include a thorough clinical examination, fine-needle aspiration (FNA) for palpable nodes, and appropriate laboratory testing, with imaging reserved for specific clinical scenarios. 1

Clinical Examination

• Evaluate for palpability, number of inguinal masses, unilateral or bilateral presentation, dimensions, mobility or fixation of nodes, and relationship to other structures 2, 1
• Assess for edema of the penis, scrotum, and/or legs, which may indicate lymphatic obstruction 2
• Document diameter of nodes, unilateral or bilateral localization, number of nodes identified in each inguinal region, and relationship to other structures 2
• Note that palpable supraclavicular, popliteal, and iliac nodes are always abnormal, as are epitrochlear nodes greater than 5 mm in diameter 3

Initial Diagnostic Testing

• Fine-needle aspiration (FNA) is the standard initial diagnostic approach for palpable inguinal lymph nodes <4 cm 1
• Laboratory assessments should include complete blood count with differential, C-reactive protein, erythrocyte sedimentation rate 4
• Consider targeted testing based on clinical suspicion:
  • Sexually transmitted infection testing if sexual risk factors are present 5
  • Tuberculosis testing if exposure history or risk factors exist 4

Imaging Considerations

• CT or MRI may be used for palpable disease to assess size, extent, location, and proximity to other structures 2, 1
• MRI is preferred when evaluating both the primary lesion and lymph node status, particularly in patients where the inguinal region is difficult to assess (e.g., obesity, previous surgery) 2
• PET/CT has limited utility in patients with non-palpable disease (sensitivity only 57% for cN0) but may be useful for quantifying disease burden in patients with confirmed positive lymph nodes 2

Management Based on FNA Results

• If FNA is negative but clinical suspicion remains high, proceed with excisional biopsy or careful surveillance 1
• If FNA is positive for malignancy, proceed with appropriate oncologic management based on the primary malignancy 1
• For inflammatory lymphadenopathy, a 6-week course of antibiotics may be appropriate, as 30-50% of palpable inguinal lymphadenopathy cases are due to inflammatory lymph node swelling rather than metastatic disease 2

When to Consider Biopsy

• Persistent lymphadenopathy beyond four weeks 4
• Presence of systemic symptoms (fever, night sweats, unintentional weight loss) 4, 3
• Lymph nodes larger than 2 cm, hard, or matted/fixed to surrounding structures 4
• Negative FNA with persistent clinical concern 1
• Biopsy options include:
  • Fine-needle aspiration (least invasive but may miss focal disease)
  • Core needle biopsy (better tissue sampling)
  • Excisional biopsy (gold standard but most invasive) 3

Important Caveats

• Avoid immediate surgical excision without prior FNA as this may lead to unnecessary morbidity 1
• Avoid corticosteroids before diagnosis as they can mask histologic findings of lymphoma or other malignancy 4, 3
• Remember that risk factors for malignancy include age older than 40 years, male sex, white race, supraclavicular location, and presence of systemic symptoms 3
• Consider that specialized testing may be required for unusual causes of lymphadenopathy, as seen in rare conditions like Kimura's Disease 6