Platinum-based chemotherapy for metastatic insulinoma harboring germline mutation in DNA damage repair pathway: A case report

Malignant insulinomas are rare neuroendocrine tumors that require management for both symptomatic control and tumor reduction. It is clinically challenging to optimize treatment strategies for refractory malignant insulinoma. We report a case of metastatic grade 3 insulinoma presented with recurrent hypoglycemia in a 23-year-old female with RAD51D p.Q192 germline mutation. During the disease course of 5 years, the tumor has continuously progressed despite locoregional therapy and multiple lines of systemic treatment. However, oxaliplatin-based chemotherapy achieved a partial response, which was maintained for two years. The hypoglycemic symptoms were controlled after the treatment response and did not recur. Platinum-based regimen could be a feasible therapeutic strategy for malignant insulinoma. The relationship between germline mutation in the DNA damage repair pathway and treatment response to platinum-based regimens in neuroendocrine tumors warrants further investigation.