Leptomeningeal carcinomatosis (LC) is a devastating complication of metastatic cancer that disproportionately affects patients with advanced breast cancer. Moreover, those with BRCA1/2-mutated disease more often experience leptomeningeal metastasis. Treatment options for LC are limited and often include significant toxicities. PARP inhibitors offer an important potential treatment for patients with BRCA1/2-mutated breast and ovarian cancers, but clinical studies excluded patients with central nervous system (CNS) metastases, including LC. Efficacy data in this area are therefore limited, although a phase I study of olaparib in glioblastoma did show CNS penetration. Here we report a case of a patient with BRCA2-mutated breast cancer and solitary recurrence in the leptomeninges with ongoing complete response to treatment with the PARP inhibitor olaparib. PARP inhibitors may be an important treatment option for patients with BRCA-mutated disease and LC, and warrant further study.