Anogenital lichen sclerosus et atrophicus lesions in a case series of cancer patients on immunotherapy.

Lichenoid reactions are one of the most frequently observed toxicities with anticancer agents and, recently, a rapid emergence of immunotherapies in oncology has hastened the need to better characterize their unique toxicity profiles, particularly for less common skin toxicities, including anogenital lichen sclerosus et atrophicus (LSA). This case series describes four patients with advanced cancer (one melanoma, two lung cancers, and one kidney tumor) developing LSA lesions while receiving an immunotherapy. Medical records from 2017 to 2020 were retrospectively reviewed. Two patients received pembrolizumab, anti-programmed cell death-1 (PD-1), one nivolumab, anti-programmed cell death-1 (PD-1), and one ipilimumab, an immune checkpoint inhibitor. LSA emerged after a median of 3 months (range, 2-4 months) from starting immunotherapy. All LSA cases were grade 2. Three cases occurred on the penis and one case on the anus. All patients improved after a specific treatment for LSA, and no LSA-related antineoplastic treatment interruption/life-threatening condition were reported. To date, this is the first case series of LSA lesions associated with immunotherapy. Early LSA recognition and management is helpful in cancer patients on immunotherapy allowing a long survival and treatment response.