Patterns of spread and anatomical prognostic factors of pre-auricular cutaneous squamous cell carcinoma extending to the temporal bone.

Abstract

Improvements can be made in the management and staging of advanced pre-auricular cutaneous squamous cell carcinoma (cSCC). We aimed to analyze radiological patterns of spread and clinico-anatomical prognostic factors. Retrospective review of 54 patients with pre-auricular cSCC (cutaneous/nodal) who underwent temporal bone resection with curative intent. Involvement of the cartilaginous external auditory canal (EAC) (79.6%) and retromandibular space (63.0%) was common. Styloid process/anterior carotid sheath (ACS) (11.1%) and bony EAC (7.4%) involvement were rare. ACS involvement resulted in high rates of involved surgical margins (100%) and poor outcomes on univariable analysis. Negative prognostic factors on multivariable analysis included salvage surgery and invasion of the bony EAC, mandible, pterygoid muscle(s), and dura. The bony EAC and ACS can form temporary barriers to tumor spread, with the latter representing a potential limit of resectability. Prognostic factors revealed can lead to the development of a more appropriate staging tool.