Complete response to dual immune checkpoint blockade in a patient with Birt-Hogg-Dubé syndrome and epithelioid angiomyolipoma.

Epithelioid angiomyolipoma (E-AML) is a rare renal tumor, which can exhibit malignant potential. Because angiomyolipomas frequently harbor TSC1/TSC2 alterations, mTOR inhibitors are commonly used. However, durable disease control remains inconsistent. The potential for long-lasting response with immune checkpoint inhibitors supports exploring their role in E-AML. We report a patient with highly symptomatic, locally advanced renal E-AML treated with first-line ipilimumab plus nivolumab. The patient experienced rapid symptomatic and radiographic improvement after treatment initiation. She subsequently developed immune-related sarcoidosis, which resolved after discontinuation of immunotherapy and with corticosteroids. Given sustained disease control, she underwent delayed nephrectomy demonstrating complete pathologic response in the primary tumor. Genomic analysis revealed a germline mutation in FLCN consistent with Birt-Hogg-Dubé syndrome. T-cell receptor sequencing identified a shared expanded T-cell clone in peripheral blood and within the tumor. With extended follow-up for over 5 years, she remains in durable remission after dual immune checkpoint blockade. To our knowledge, this is the first report of dual immune checkpoint blockade in renal E-AML. This case demonstrates that first-line ipilimumab plus nivolumab can induce deep, durable response-including complete pathologic response-in a rare malignancy with limited standard treatment options, supporting further evaluation of immunotherapy in this disease.