The reported case is a 61-year-old woman, admitted for gradual onset of gait disturbances and dysphonia. The serum immunological panel revealed anti-Yo autoantibodies, suggestive of a paraneoplastic syndrome (PNS). A PET-CT revealed a suspicious left ovarian mass with retroperitoneal nodal involvement, and the histological assessment of surgical samples confirmed a FIGO IIIC high-grade serous ovarian cancer (HGSOC). Deemed inoperable at first, the patient was treated by carboplatin and paclitaxel chemotherapy, after which she refused surgical debulking. At the end of her systemic treatment, the patient only experienced a transient improvement of the cerebellar ataxia. Despite the suboptimal oncological treatment, the patient still presents stable disease and is free of progression 7 years from her diagnosis. This case study illustrates the favorable effect of PNS occurrence on oncological outcome in a patient with advanced HGSOC. The absence of recurrence despite the presence of residual disease after the systemic treatment is unusual and could be related to the PNS.