A 58-year-old man with a 3 cm, indurated, ulcerated nodule on his left cheek is diagnosed with well-differentiated squamous cell carcinoma. Regarding the clinical features, histopathology, and prognostic factors of cutaneous SCC, all of the following statements are true EXCEPT:

Explanation

## Prognostic Factors in Cutaneous Squamous Cell Carcinoma ### Overview Prognostic factors in SCC determine treatment intensity, surveillance, and counseling. NEET PG frequently tests understanding of which factors predict recurrence and metastasis. ### Correct Prognostic Factors **Key Point:** Marjolin ulcers (SCC arising in chronic wounds, scars, or areas of chronic inflammation) have significantly worse prognosis: - Higher recurrence rates (up to 30%) - Increased metastatic potential - Often present at advanced stage - Require wider margins and closer follow-up **High-Yield:** Histologic grade is one of the strongest independent predictors: - **Well-differentiated:** Better prognosis, lower recurrence - **Poorly-differentiated:** Worse prognosis, higher recurrence and metastasis - Grade correlates with depth of invasion and biological behavior **Clinical Pearl:** Perineural invasion (PNI) is a critical adverse prognostic factor: - 5-fold higher risk of local recurrence - Associated with worse overall survival - Indicates aggressive tumor biology - Requires consideration of adjuvant radiation therapy ### Why Option 3 (Clark Level) Is the Answer **Key Point:** In cutaneous SCC, **tumor thickness (Breslow depth)** is far more important than Clark level for predicting metastatic risk. Clark level is the primary depth classification for melanoma, not SCC. In SCC, thickness >4 mm is associated with significantly increased metastatic risk. Confusing Clark level with thickness is a classic NEET PG trap. ### Prognostic Factors Summary Table | Factor | Impact | Notes | | --- | --- | --- | | **Tumor thickness** | **High** | >4 mm = increased metastatic risk | | **Histologic grade** | **High** | Poorly-differentiated = worse prognosis | | **Perineural invasion** | **High** | 5× higher recurrence risk | | **Location** | **Moderate** | Ear, lip, non-facial = worse | | **Marjolin ulcer** | **High** | Worse prognosis, higher recurrence | | **Immunosuppression** | **Moderate** | Higher recurrence and metastasis | | **Size >2 cm** | **Moderate** | Increased recurrence | | **Clark level** | **Low/None** | Not used in SCC (melanoma classification) | **Mnemonic: THUMP** — **T**hickness (Breslow), **H**istologic grade, **U**lceration, **M**arjolin/site, **P**erineural invasion.