Perineural Invasion in Aggressive Skin Carcinomas of the Head and Neck

Abstract

Introduction: Perineural invasion is a well-recognized form of cancer dissemination. However, it has been reported only in few papers concerning cutaneous carcinomas (basal cell, BCC, and squamous cell, SCC). Moreover, the incidence is considered to be very low. Niazi and Lambert [Br J Plast Surg 1993;46:156–157] reported only 0.18% of perineural invasion among 3,355 BCCs. It is associated with high-risk subtypes, as morphea-like, as well as with an increased risk of local recurrence. No paper was found in the literature looking for perineural invasion in very aggressive skin cancers with skull base extension, with immunohistochemical analysis. Methods: This is a retrospective review, including 35 very advanced skin carcinomas with skull base invasion (24 BCCs and 11 SCCs, operated on at a single institution from 1982 to 2000). Representative slides were immunohistochemically evaluated with antiprotein S-100, in order to enhance nerve fibers and to detect perineural invasion. The results were compared to 34 controls with tumors with a good outcome, treated in the same time frame at the same Institution. Results: Twelve (50.0%) of the BCCs with skull base invasion had proven perineural invasion, as opposed to only 1 (4.6%) of the controls, and this difference was statistically significant (p < 0.001). Regarding SCCs, 7 aggressive tumors (63.6%) showed perineural invasion compared to only 1 (10.0%) of the controls, but this difference did not reach significance (p = 0.08), due to the small number of cases. Conclusions: In this series, it was demonstrated that immunohistochemically detected perineural invasion was very prevalent in advanced skin carcinomas. In addition, it was statistically associated with extremely aggressive BCCs with skull base invasion.

Histopathological features of clinical perineural invasion of cutaneous squamous cell carcinoma of the head and neck and the potential implications for treatment

“…However, the existence of perineural lymphatics was discounted. [48][49][50] The haphazard course of nerves makes sectioning and tracing nerves a challenge, and routine 2D sections may not appreciate the complete 3D structure. 47 PNI can be overlooked unless a high degree of suspicion is applied with careful histological technique.…”

Histopathological Variants of Cutaneous Squamous Cell Carcinoma: A Review

“…Perineural involvement (PNI) is thought to occur in approximately 14% of all SCC tumors arising on the head or neck [66], and is indicative of the inherently aggressive nature of the tumor. Accordingly, tumors with PNI will show a much greater likelihood of local recurrence (23%) relative to those without (9%) [67].…”

“…Clinically, perineural involvement can present as conventional SCC with an associated numbness, facial muscle weakness, twitching, or visual change. However, there are often no clinical symptoms of nerve involvement, and PNI is most frequently diagnosed microscopically [66, 67]. …”

“…Usually, tumor cells arranged in solid or sheet-like patterns are less invasive, and will pass around the nerve or vessel. In contrast, individual tumor cells will generally penetrate and track along associated structures [66, 67]. …”

Basal Cell Carcinoma

“…Considering large published series that encompass all 'ordinary' BCCs, it seems rather uncommon, oscillating from 0.19% to 0.49% . Some authors reported an increased frequency of 3.8% in cancers treated by Mohs' micrographic surgery (Cernea et al, 2009). The cancer may extend cylindrically, several cells thick, around the nevre beneath the perineurum (Schwartz, 2008).…”