“…Cutaneous lichenoid reactions are one of the most common dermatologic toxicities associated with immunotherapy, affecting between 0.5% and 17% of patients treated, though the incidence is sporadically reported and is likely to be underestimated (Geisler et al, 2020;Hwang et al, 2016;Sibaud et al, 2017;Wongvibulsin et al, 2021). These events often spare the oral mucosa, or may be underdiagnosed, but there have been numerous reports of oral lichen planus (OLP)-like reactions with or without cutaneous or other mucosal involvement in patients on nivolumab, pembrolizumab, and atezolizumab (Bhattacharyya et al, 2020;Coleman et al, 2019;Enomoto et al, 2019;Hashimoto et al, 2021;Lacouture & Sibaud, 2018;Nguyen et al, 2019;Obara et al, 2018;Owosho et al, 2016;Schaberg et al, 2016;Shazib et al, 2020;Shi et al, 2016;Sibaud et al, 2017;Vigarios et al, 2017). Clinical features of OLP-like reactions include white reticulations (Wickham striae) with associated erythema and/or ulcers affecting the tongue, buccal mucosa, hard and soft palatal mucosa, lip mucosa, and gingiva, though the buccal mucosa and ventral tongue appear to be most commonly affected (Figure 1) (Bhattacharyya et al, 2020;Enomoto et al, 2019;Lacouture & Sibaud, 2018;Nguyen et al, 2019;Obara et al, 2018;Owosho et al, 2016;Schaberg et al, 2016;Shazib et al, 2020;Shi et al, 2016;Sibaud et al, 2017;Vigarios et al, 2017).…”