Inguinofemoral Lymph Nodes are the Primary Site of Metastasis in Vulvar Squamous Cell Carcinoma
The inguinofemoral lymph nodes are the most likely primary site of metastasis for this patient's vulvar squamous cell carcinoma. 1
Lymphatic Drainage Pattern in Vulvar Cancer
Vulvar cancer follows a predictable pattern of lymphatic spread:
- The inguinofemoral lymph nodes are the first echelon nodes that receive lymphatic drainage from the vulva
- Metastatic spread starts in the inguinal lymph nodes before progressing to other nodal regions 1, 2
- For unilateral tumors, metastases are typically found in the lymph nodes on the same side as the primary tumor 2
In this 76-year-old woman with a left-sided vulvar lesion, the left inguinofemoral lymph nodes would be the most likely site of initial metastasis.
Prognostic Significance of Lymph Node Status
Lymph node status is the single most important prognostic factor in vulvar cancer:
- 5-year survival rate is 86% for vulvar-confined disease
- Survival drops to 57% with regional lymph node metastases 1, 3
- The enlarged lymph nodes seen on CT in this patient significantly worsen her prognosis
Risk Factors and Disease Characteristics
This patient has several notable risk factors:
- Advanced age (76 years)
- History of lichen sclerosus (present for 4 years)
- Smoking history (35 pack-years)
- Large tumor size (2.5 cm)
These factors increase both her risk for developing vulvar cancer and for having nodal metastases at presentation.
Sentinel Lymph Node Considerations
While sentinel lymph node biopsy has become standard practice for many vulvar cancers, this patient would not be a candidate due to:
- Tumor size >2 cm
- Ulcerative characteristics
- Clinical evidence of nodal metastasis on imaging 1
Imaging Findings and Management Implications
The CT findings of enlarged lymph nodes are concerning for metastatic disease and would guide management:
- US with Doppler and US-guided FNAB can confirm lymph node metastases with high sensitivity (93%) and specificity (100%) 1
- For patients with confirmed nodal metastases, treatment typically includes wider radiation fields encompassing the primary tumor, pelvis, and groin nodal basins 1
Conclusion
Based on the natural lymphatic drainage pattern of the vulva and the established patterns of metastatic spread in vulvar cancer, the inguinofemoral lymph nodes represent the most likely primary site of metastasis in this patient with vulvar squamous cell carcinoma.