Successful use of immunotherapy to treat advanced cutaneous squamous cell carcinoma in recessive dystrophic epidermolysis bullosa.

Recessive dystrophic epidermolysis bullosa (RDEB) is a multisystem inherited disorder associated with fragile skin, blister formation and poor wound healing. Patients with RDEB are at significantly increased risk of recurrent and aggressive cutaneous squamous cell carcinoma (cSCC) and because of their disease complexity, conventional therapies may not be possible. Recent advances in cancer immunotherapy have led to the successful use of immune checkpoint inhibitors (ICIs) in melanoma and other malignancies. However, the effects of ICIs in patients with cSCC and RDEB are currently unknown. A 30-year-old woman with RDEB and multiple unresectable cSCCs was found to have high tumour mutational burden and PD-L1 (programmed cell death-ligand 1) expression. She was started on an ICI, which yielded disease control and was well tolerated. Furthermore, her RDEB wounds improved. This case demonstrates successful use of immunotherapy for advanced cSCC in RDEB, a disease that is often challenging to treat with local therapies.