Pseudoprogression of cutaneous squamous cell carcinoma invading the super vermillion border following programmed death-1 inhibitor monotherapy.

Abstract

A 55-year-old woman with a moderately differentiated cutaneous squamous cell carcinoma (cSCC) of the upper lip experienced initial tumour growth and new lymphadenopathy after starting immunotherapy with Cemiplimab, but achieved complete remission with no adverse events after five infusions. This case underscores the potential of immunotherapy for cSCC in sensitive head and neck areas and illustrates the phenomenon of pseudoprogression, where apparent tumour growth can occur before clinical improvement.