Pemphigus Herpetiformis-Type Drug Reaction Caused by Programmed Cell Death Protein-1 Inhibitor Treatment.

Reports of immune-related adverse events caused by programmed cell death protein-1 inhibitor are becoming increasingly frequent. Herein, we report the first case of pemphigus herpetiformis-type drug reaction presented after the treatment of tislelizumab (6 cycles) in a primary non-small cell lung carcinoma patient. A 56-year-old Chinese man was referred to our department for pruritic annulare erythema and blister for two weeks. Histological finding revealed blister formation in the epidermis and eosinophilic infiltration in the blister fluid. Direct immunofluorescence showed intercellular deposition of IgG and C3 within the lower part of epidermis. Serum anti-intercellular antibodies were positive at 1:100 dilution. Based on history and clinicopathological correlation, herpetiformis-type drug-induced pemphigus was diagnosed, which was possibly be induced by tislelizumab. To the best to our knowledge, there is no report of pemphigus herpetiformis-type drug-induced reaction associated with programmed cell death protein-1 inhibitor treatment.