Successful Treatment of Pembrolizumab-Induced Severe Capillary Leak Syndrome and Lymphatic Capillary Dysfunction

Although capillary leak syndrome has a high mortality rate, its trigger, diagnosis, and treatment remain a challenge to clinicians because of the poor understanding of its mechanism and lack of treatment guidelines. With the extended use of immune checkpoint inhibitors in modern oncology, immune checkpoint inhibitor–associated immune-related adverse events have also expanded. We present a case of pembrolizumab-induced capillary leak syndrome and lymphatic capillary dysfunction in which the patient had an excellent clinical response to a tailored treatment strategy.