Paraneoplastic opsoclonus-myoclonus syndrome as a presentation of high grade serous ovarian cancer.

Opsoclonus-myoclonus syndrome (OMS) is a rare paraneoplastic disorder that is most often seen in association with pediatric neuroblastoma, breast cancer, small cell lung cancer, and prostate cancer. There are only three previously documented cases relating paraneoplastic OMS to ovarian cancer. We present a unique case of OMS related to a stage IIIC high grade serous ovarian carcinoma in a patient with germline BRCA2 mutation, with ten years of clinical follow up. This case report is presented to document the rare association of OMS with epithelial ovarian cancer. Additionally, in this case, OMS and epithelial cancer were successfully treated with medical therapy alone. This is the first report to our knowledge to document ten years of clinical follow up in this context, and to report that the association may not be evident at the time of ovarian cancer recurrence.