Staging of Squamous Cell Carcinoma of the Foot with Inguinofemoral Lymphadenopathy
This 4 cm squamous cell carcinoma of the foot with inguinofemoral lymphadenopathy requires pathologic confirmation of nodal involvement, but if confirmed positive, represents at minimum Stage III disease (regional lymph node metastasis).
Critical Staging Requirement
The presence of inguinofemoral lymphadenopathy does not automatically confirm metastatic disease, as enlarged lymph nodes can be reactive from chronic inflammation or infection 1. Ultrasound-guided fine needle aspiration (FNA) of the enlarged inguinal lymph nodes must be performed immediately to determine if the lymphadenopathy represents metastatic SCC 1. If FNA is inconclusive despite repeated attempts, surgical biopsy is required 1.
Staging Based on Nodal Status
If Lymph Nodes Are Positive for Metastatic SCC:
- The tumor is classified as Stage III (T2N1M0 or higher) based on the 4 cm primary tumor size and confirmed regional lymph node involvement 2
- The 4 cm tumor size alone places this in the T2 category (≥2 cm but <5 cm) 2
- Regional lymph node involvement automatically elevates staging to at least Stage III regardless of primary tumor characteristics 1
If Lymph Nodes Are Negative for Metastatic SCC:
- The tumor would be classified as Stage II (T2N0M0) based solely on the 4 cm primary tumor size without nodal involvement 2
- However, this 4 cm tumor still requires complete staging workup given its size 1
Additional Staging Workup Required
Given the 4 cm tumor size, comprehensive staging must include 1, 2:
- FDG-PET with CT scanning to evaluate for systemic and lymph node metastases (preferred modality) 1
- If PET unavailable, CT or MRI of chest, abdomen, and pelvis to identify systemic or additional lymph node metastases 1
- MRI of the foot to assess tumor extent and involvement of underlying structures (tendons, nerves, vessels, bone) given the anatomically complex location 1, 2
Important Staging Pitfalls
Do not assume clinically palpable lymph nodes are metastatic without pathologic confirmation - reactive lymphadenopathy is common and can mimic metastatic disease 1. Conversely, up to 25% of clinically negative lymph nodes may harbor micrometastases, emphasizing the critical importance of appropriate nodal evaluation 3.
The foot location is generally considered lower risk for metastasis compared to other anatomic sites, but the 4 cm size (≥2 cm) and presence of lymphadenopathy elevate this patient's risk profile substantially 2, 4, 5. Inadequate initial evaluation and treatment of foot SCC is common and leads to more aggressive definitive treatment requirements 4, 5.