Durable response to pembrolizumab in microsatellite instability‐high advanced adrenocortical carcinoma

INTRODUCTION: Advanced adrenocortical carcinoma has a poor prognosis and is treated with chemotherapy that includes mitotane with etoposide, doxorubicin, and cisplatin as first‐line therapy. However, second‐line therapy has not been determined yet. Pembrolizumab has been approved for high microsatellite instability for which standard treatments have failed. CASE PRESENTATION: Here, we present a patient with advanced adrenocortical carcinoma treated with complete surgical resection. 21 months later, he had local and metastatic recurrences. After four cycles of first‐line therapy, we switched to pembrolizumab because microsatellite instability‐high was detected in his tumor. He has received mitotane and pembrolizumab for 15 months, and this has exerted a radiographical response without severe adverse events. CONCLUSION: We presented a patient with microsatellite instability‐high advanced adrenocortical carcinoma treated with pembrolizumab and mitotane.