Perineural Spread and Base of Skull Involvement in Cutaneous Squamous Cell Carcinoma—A Critical Review from an Endemic Region

Perineural spread (PNS) from cutaneous squamous cell carcinoma (cSCC) to the skull base is increasingly recognised as a route of cancer spread. Management historically involved definitive radiotherapy to treat PNS at the skull base. In the endemic region with modern magnetic resonance neurogram (MRN) and skull base surgical expertise, the outcome has improved over the years. With the advent of immunotherapy, the outcome may be maintained while preserving critical organs in the head and neck region. We conducted a critical review of the literature to establish the treatment outcomes and pattern of failure as practice evolved. Furthermore, we described our skull base surgical and radiotherapy management guideline and outlined the emerging paradigm shift in the immunotherapy era.