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

## TL;DR

A woman with lip cancer initially showed signs of tumor growth after immunotherapy, but later achieved full remission, highlighting the potential of this treatment and the concept of pseudoprogression.

## Contribution

This case report presents a rare instance of pseudoprogression in cutaneous squamous cell carcinoma treated with a PD-1 inhibitor.

## Key findings

- The patient showed initial tumor growth and new lymphadenopathy after starting Cemiplimab.
- Complete remission was achieved after five infusions with no adverse events.
- The case illustrates the phenomenon of pseudoprogression in immunotherapy for cSCC.

## 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.