Paraneoplastic cerebellar degeneration is a disorder caused by an immune-mediated attack of cerebellar cells by cross-reacting antibodies to target tumor cells. It is most commonly seen in ovarian cancer, uterine cancer, breast cancer, Hodgkin lymphoma, and small cell lung carcinoma. Anti-Yo, anti-Tr, and anti-Hu are some of the known antibodies that cause the disorder.

Early symptoms include nausea and dizziness. Symptoms progress over days to months to include vertigo, nystagmus, ataxia, and dysarthria. Some syndromes may also present with concomitant encephalopathy. Prognosis depends on early diagnosis and treatment of the underlying malignancy.