What is the appropriate management for an adult patient with an inguinal lymph node measuring 2.3 x 1.6 x 2.7cm?

Management of a 2.3 x 1.6 x 2.7cm Inguinal Lymph Node

Fine-needle aspiration (FNA) is the mandatory first step for this lymph node, followed by inguinal lymph node dissection if positive for malignancy, or excisional biopsy if negative or inconclusive. 1

Initial Diagnostic Workup

The size of this lymph node (2.7cm in largest dimension, approximately 2.3cm in short axis) places it in the intermediate category requiring immediate tissue diagnosis. 2

Perform FNA as the initial diagnostic procedure: 1, 3

• This node measures between 2-4cm, making FNA the standard first approach 2
• If FNA is positive for malignancy, proceed directly to therapeutic management rather than further diagnostic procedures 1
• If FNA is negative or inconclusive, confirm with excisional biopsy 1, 3

Simultaneously evaluate for primary malignancy sources: 1

• Examine for penile cancer (70% of palpable inguinal nodes in penile cancer represent metastatic disease) 1
• Examine for vulvar cancer, which commonly presents with inguinal lymphadenopathy 1
• Examine lower extremities, perineum, and genital region for infectious sources, as 30-50% of palpable inguinal lymphadenopathy is inflammatory rather than malignant 1, 3

Management Based on FNA Results

If FNA is Positive for Malignancy

Proceed with oncologic management based on the primary tumor identified: 1

For penile cancer with positive FNA: 2

• This node size (2-4cm) qualifies for neoadjuvant cisplatin-based chemotherapy (paclitaxel, ifosfamide, and cisplatin - TIP regimen) prior to inguinal lymph node dissection (ILND) 2
• Neoadjuvant chemotherapy should be considered the standard, with a 50% objective response rate and improved progression-free survival 2
• After chemotherapy response, perform bilateral ILND 2
• Consider pelvic lymph node dissection if ≥2 positive inguinal nodes or extranodal extension are found 1

For vulvar cancer with positive FNA: 2

• Perform bilateral inguinofemoral lymphadenectomy 2
• Consider neoadjuvant chemoradiation for locally advanced disease 2

If FNA is Negative or Inconclusive

Perform excisional biopsy for definitive diagnosis: 1, 3

• Excisional biopsy is the gold standard when definitive diagnosis is needed, providing the most tissue for pathologic evaluation 3
• Do not rely on surveillance alone given the node size exceeds normal parameters 3

Obtain cross-sectional imaging before biopsy: 3

• CT abdomen and pelvis with IV contrast is preferred to assess extent, location, and relationship to surrounding structures 3
• Evaluate for pelvic lymph node involvement 1

Critical Context: Normal vs. Pathologic Size

This lymph node is definitively enlarged and requires tissue diagnosis:

• Normal inguinal lymph nodes have a mean short axis of 5.4mm, with 8.8mm at two standard deviations above the mean 4
• Your node measures 23mm in short axis, nearly 3 times the upper limit of normal 4
• Size alone mandates diagnostic evaluation regardless of other features 3

Common Pitfalls to Avoid

Do not delay FNA based on imaging characteristics alone: 1, 3

• Even if the node appears to have benign features on imaging, the size mandates tissue diagnosis 3
• CT and MRI have limited sensitivity (58-60%) for detecting metastases in borderline enlarged nodes 3

Do not treat with antibiotics and observe: 5

• Antibiotic treatment for 3-6 weeks before ILND in patients with palpable inguinal nodes is not recommended 5
• This approach delays definitive diagnosis and treatment 5

Do not perform sentinel node biopsy at this size: 2

• Sentinel node biopsy has insufficient sensitivity (71%) and is only appropriate for non-palpable nodes in high-risk patients 2
• This node is clearly palpable and requires complete evaluation 2

Follow-Up After Negative Biopsy

If excisional biopsy confirms reactive/benign lymphadenopathy: 3

• Clinical examination of the inguinal region every 3 months 3
• Re-biopsy if the node enlarges further or new systemic symptoms develop 3