Is a metastasis to the right inguinal lymph node from a melanoma on the right toe considered a regional nodal disease?

Regional Nodal Disease Classification for Right Inguinal Node Metastasis from Right Toe Melanoma

Yes, metastasis to the right inguinal lymph node from a right toe melanoma is definitively considered regional nodal disease, classified as Stage III melanoma. 1

Anatomic Drainage and Regional Node Definition

The inguinal lymph nodes represent the regional nodal basin for lower extremity melanomas, including those arising from the toes. 1 This anatomic relationship is fundamental to melanoma staging:

• Lower extremity melanomas drain predictably to the ipsilateral inguinal nodes as their first-echelon lymphatic basin 1
• This makes inguinal node involvement regional disease (Stage III), not distant metastatic disease (Stage IV) 1
• The presence of regional nodal metastases automatically upgrades the patient to at least Stage IIIA disease, depending on primary tumor characteristics and extent of nodal involvement 2

Clinical Management Implications

Surgical Approach

Radical inguinal lymph node dissection is recommended after pathological confirmation (cytology or histology) and adequate staging to exclude distant disease. 1

Key surgical considerations include:

• Complete inguinal dissection is preferred over "node picking" because the number of involved lymph nodes is typically greater than anticipated, and the location of additional involved nodes cannot be accurately predicted 1
• Imaging should determine the extent of dissection: If imaging shows no iliac/pelvic involvement, inguinal dissection alone is sufficient; if iliac disease is present, combined ilio-inguinal dissection should be performed 1
• The MSLT-I trial data showed that inclusion of pelvic dissection does not increase long-term lymphedema risk 1

Adjuvant Systemic Therapy

Following complete surgical resection of Stage III disease, adjuvant therapy significantly reduces recurrence risk: 2

• Anti-PD-1 immunotherapy (nivolumab or pembrolizumab) is first-line adjuvant treatment, with hazard ratios for recurrence of 0.72 (nivolumab) and 0.61 (pembrolizumab) 3, 2
• For BRAF V600 mutation-positive melanomas, dabrafenib plus trametinib is an alternative option (HR 0.52 for recurrence) 3, 2
• BRAF mutation testing is mandatory before finalizing the adjuvant treatment plan 3

Important Staging Distinctions

Critical pitfall to avoid: Do not confuse regional nodal disease with distant metastatic disease. 1

• Inguinal nodes = Stage III (regional disease, potentially curable with surgery plus adjuvant therapy)
• Distant sites (lung, liver, brain, non-regional nodes) = Stage IV (systemic disease requiring different treatment approach) 4
• The 10-year melanoma-specific survival for Stage III disease ranges from 88% (IIIA) to 60% (IIIB-C), compared to only 24% for Stage IIID and 43% for Stage IV with modern dual checkpoint blockade 2

Staging Workup Required

Before proceeding with lymphadenectomy, complete staging must exclude distant disease: 1

• PET-CT is preferred for comprehensive staging 1
• Document serum LDH level, as elevation indicates worse prognosis 4
• Pathological confirmation of nodal disease before surgery is mandatory 1, 3

This distinction between regional (Stage III) and distant (Stage IV) disease fundamentally changes both surgical approach and systemic therapy selection, making accurate classification essential for optimal outcomes.