Reversible cerebellar ataxia due to ovarian teratoma.

Cerebellar dysfunction is a classic paraneoplastic syndrome associated with various types of cancer, including gynecological and breast tumors, small-cell lung cancer, thymoma, and Hodgkin's lymphoma. We present a 22-year-old woman with acute cerebellar ataxia that subsided upon removal of an ovarian teratoma. This patient may represent a new category of immune-mediated cerebellar ataxia that is reversible with removal of an underlying tumor.