Stevens–Johnson syndrome associated with TS‐1 in a patient with gastric cancer: A case report.

TS‐1, an effective anticancer drug that consists of tegafur, gimeracil and oteracil, has been increasingly used for the treatment of many types of cancer. However, few studies investigate its cutaneous adverse reactions. Here, we report a female patient with gastric cancer treated with TS‐1 after a gastrectomy, who then developed Stevens–Johnson syndrome, a cutaneous and potentially life‐threatening adverse reaction. This is the first case report about a Grade IV toxic reaction associated with TS‐1. The patient presented with systemic symptoms of erythematous macules, vesicle formation, erosions, binocular ptosis and oedema of the lower eyelid conjunctiva. After 3 weeks of hospitalization with drug treatment and discontinuation of TS‐1, her symptoms were fully relieved and did not recur because the chemotherapy regimen was adjusted to modified FOLFOX6. According to the comprehensive analysis and the score of both the Naranjo assessment scale and algorithm of drug causality for epidermal necrolysis, we have drawn the preliminary conclusion that this is TS‐1‐induced Stevens–Johnson syndrome. [ABSTRACT FROM AUTHOR]