Multiple oral erosions and ulcers in a patient with malignant melanoma

A man in his 70s presented with a 3 week history of multiple painful, bleeding oral erosions and ulcers. He was receiving immunotherapy (with a phase I trial programmed cell death ligand 1 [PD-L1] inhibitor) for metastatic malignant melanoma. He had received systemic intravenous methylprednisolone to manage a skin eruption for one week before the onset of oral lesions, which were thought to be immunotherapy related. Examination showed numerous, well defined erosions and ulcers with raised, irregular pseudomembranous borders and outer erythematous rings on the lower lip, oral commissures, dorsal tongue, and buccal mucosa (fig 1).