Background A 52-year-old white female presented with sudden onset of light-headedness followed by diplopia, horizontal vertigo and severe nystagmus with oscillopsia. She had previously been in good health. MRI of the brain was normal. Lumbar puncture revealed monocytic pleocytosis. During her initial admission, the patient improved to some degree and was discharged with a possible diagnosis of viral meningitis. After a few weeks, the patient's condition worsened and further evaluation was initiated. Examination revealed an unsteady widespread gait, severe nystagmus and mild dysarthria. A general and gynecological examination was otherwise unremarkable. Investigations General physical and gynecological examinations, MRI of the brain, lumbar punctures, electroencephalogram, transvaginal ultrasound, mammogram, tumor markers, anti-neuronal antibodies, colonoscopy, whole-body positron emission tomography scan, laparoscopy and biopsies. Diagnosis Stage HIC endometrioid adenocarcinoma of the ovary with paraneoplastic cerebellar degeneration. Management Tumor cytoreduction, plasmapheresis, total abdominal hysterectomy, bilateral salpingo-oophorectomy, bilateral pelvic and para-aortic lymph-node dissection, total omentectomy, carboplatin and paclitaxel chemotherapy, rehabilitation, and speech therapy.