Adrianna Zahorowska, Edyta Śliwak, Natalia Lerch, Karolina Engel-Eliasz, Adriana Szczęch, Mariola Krzyścin, Piotr Hajdasz, Aleksandra Marciniak, Agnieszka Brodowska, Andrzej Starczewski, Iwona Szydłowska
Background: Paraneoplastic neurological syndromes are rare immune-mediated disorders that may represent the first clinical manifestation of an underlying tumor. Case Report: This report describes a 58-year-old woman with rapidly progressive cerebellar dysfunction and anti-Yo antibodies in serum and cerebrospinal fluid. Definite PNS was diagnosed according to the PNS-Care Score criteria (score: 10/10). Oncological evaluation revealed FIGO IIIC high-grade serous ovarian carcinoma (HGSOC) with extensive peritoneal dissemination. Despite corticosteroids, cytoreductive surgery, and carboplatin-paclitaxel chemotherapy, neurological disability progressed, although tumor control was achieved. Methods: A PRISMA-guided review of PubMed and Scopus identified 33 studies of PNSs associated with ovarian tumors published between 2016 and 2026. Results: Anti-NMDAR encephalitis, mainly associated with ovarian teratomas, generally showed favorable recovery, whereas anti-Yo-associated cerebellar degeneration, predominantly linked to epithelial ovarian malignancies, had poor neurological outcomes. Conclusions: Prompt antibody testing, oncological investigation, and multidisciplinary treatment are essential, although anti-Yo-associated neurological deficits may be irreversible.