Perineural infiltration of cutaneous squamous cell carcinoma and basal cell carcinoma without clinical features.

Purpose: To review the factors that influence outcome and patterns of relapse in patients with cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) with perineural infiltration (PNI) without clinical or radiologic features, treated with surgery and radiotherapy.

Methods And Materials: Between 1991 and 2004, 222 patients with SCC or BCC with PNI on pathologic examination but without clinical or radiologic PNI features were identified. Charts were reviewed retrospectively and relevant data collected. All patients were treated with curative intent; all had radiotherapy, and most had surgery. The primary endpoint was 5-year relapse-free survival from the time of diagnosis.

Results: Patients with SCC did significantly worse than those with BCC (5-year relapse-free survival, 78% vs. 91%; p < 0.01). Squamous cell carcinoma with PNI at recurrence did significantly worse than de novo in terms of 5-year local failure (40% vs. 19%; p < 0.01) and regional relapse (29% vs. 5%; p < 0.01). Depth of invasion was also a significant factor. Of the PNI-specific factors for SCC, focal PNI did significantly better than more-extensive PNI, but involved nerve diameter or presence of PNI at the periphery of the tumor were not significant factors.

Conclusions: Radiotherapy in conjunction with surgery offers an acceptable outcome for cutaneous SCC and BCC with PNI. This study suggests that focal PNI is not an adverse feature.