A Case of Late and Lethal Trousseau's Syndrome Induced by Pembrolizumab in Lung Adenocarcinoma.

Trousseau's syndrome is a relatively rare reported event in immunotherapy-related clinical trials, mostly occurring in the early period of immune checkpoint inhibitor (ICI) therapy. Here, we report an unusual case of late and lethal Trousseau's syndrome during pembrolizumab maintenance therapy in a lung adenocarcinoma harboring tumor protein p53 (TP53) mutation. The patient has experienced severe coagulation abnormalities manifesting as cerebral infarction, partial infarction of both kidneys and spleen after 23 cycles of pembrolizumab use and was resistant to anticoagulants. The late occurrence of coagulation abnormalities in this case reveals a possible correlation between TP53 mutations and Trousseau's syndrome when patients are treated with ICIs.