What is the initial workup and treatment for squamous cell carcinoma (SCC) of the upper extremity?

Workup for Squamous Cell Carcinoma of the Upper Extremity

For cutaneous squamous cell carcinoma (cSCC) of the upper extremity, obtain a diagnostic biopsy (punch, shave, or excisional) with adequate depth to assess tumor characteristics, followed by risk stratification to determine the need for imaging and lymph node evaluation. 1

Initial Diagnostic Biopsy

• Perform punch biopsy, shave biopsy, or excisional biopsy depending on lesion morphology and location, ensuring adequate size and depth to reach mid-subcutaneous tissue for accurate diagnosis and staging 1
• Provide the pathologist with critical clinical information: patient age, anatomic location (upper extremity), lesion size, history of immunosuppression, organ transplantation, radiation exposure, or prior skin cancers 1
• Request specific pathologic assessment including: tumor depth (modified Breslow measurement excluding scale/crust), degree of differentiation, presence of aggressive histologic subtypes (infiltrative strands, single cells, small nests), perineural invasion, lymphovascular invasion, and invasion of deeper structures (fascia, muscle, bone) 1
• Consider repeat biopsy if initial specimen is inadequate for accurate diagnosis or if clinical suspicion remains high despite negative initial pathology 1

Risk Stratification

High-risk features requiring additional workup include: 1, 2

• Tumor depth >2 mm (modified Breslow measurement)
• Poor histologic differentiation
• Perineural or lymphovascular invasion
• Tumor diameter ≥5 cm
• Recurrent tumor
• Immunosuppression (organ transplant recipients)
• Invasion of underlying structures (tendons, nerves, vessels, bone)

Imaging for Primary Tumor Assessment

• For tumors ≥5 cm in diameter or overlying anatomically complex sites (near major vessels, nerves, or joints of the upper extremity), obtain MRI to assess tumor extent and involvement of underlying structures 1, 3, 4
• CT scanning may be substituted if MRI is unavailable, though MRI is preferred for soft tissue detail 1
• Imaging is particularly important in the upper extremity to evaluate proximity to neurovascular bundles, tendons, and bone before surgical planning 1, 3

Regional Lymph Node Evaluation

• Perform clinical examination of regional lymph nodes (axillary and epitrochlear basins for upper extremity lesions) at initial presentation 1
• If lymph nodes are clinically palpable, obtain ultrasound-guided fine needle aspiration (FNA) to assess for metastatic disease 1, 3, 4
• If FNA is inconclusive with persistent clinical suspicion, proceed to surgical biopsy 1
• If lymph node biopsy is positive for metastatic SCC, plan regional lymph node dissection (typically axillary dissection for upper extremity primary tumors), which can be performed at the time of primary tumor excision 1
• Do NOT perform elective lymph node dissection without proven nodal involvement due to significant morbidity including lymphedema 1
• Consider sentinel lymph node biopsy for high-risk tumors when lymph nodes are not clinically palpable 3

Staging for Distant Metastases

For high-risk tumors (≥5 cm diameter, deep invasion, or symptoms suggesting metastatic spread such as bone pain, abnormal liver function, or dyspnea): 1

• First-line: FDG-PET with CT scanning to evaluate for systemic and lymph node metastases 1
• Note that PET scanning may show nonspecific uptake from chronic wounds or reactive lymph nodes; correlation with CT improves specificity 1
• If PET unavailable: CT or MRI of chest, abdomen, and pelvis to identify systemic or lymph node metastases 1
• If CT unavailable: abdominal ultrasonography and/or bone scanning may help identify systemic metastases 1

Multidisciplinary Discussion

• Present all cases at a multidisciplinary tumor board with dermatology, plastic surgery, histopathology, and oncology to review histology and plan staging and treatment 1, 4
• This is particularly important for upper extremity tumors where functional preservation and reconstruction planning are critical 1, 4

Common Pitfalls to Avoid

• Inadequate biopsy depth leading to underestimation of tumor invasion and incorrect risk stratification 1
• Failure to assess regional lymph nodes in high-risk cases, which can lead to missed metastatic disease and poor outcomes 1, 3, 4
• Delaying imaging for large tumors (≥5 cm) or those in anatomically complex locations, resulting in inadequate surgical planning 1, 3
• Overlooking immunosuppression history (organ transplant, chronic immunosuppressive medications), which significantly increases recurrence and metastatic risk 1, 2
• Not providing adequate clinical information to the pathologist, leading to incomplete pathologic assessment 1

Follow-up Planning

• Schedule regular surveillance examinations every 3-6 months for the first 2 years to monitor for local recurrence, regional lymph node involvement, and new primary tumors 3, 4
• Upper extremity SCCs have high local recurrence rates (recurrence-free survival 67% at 5 years), necessitating vigilant follow-up 5
• Web space location, multiple tumors, and bilateral involvement increase recurrence risk in upper extremity lesions 5