Gross cerebellar paraneoplastic neurological disorder in a patient with an occult breast cancer.

Paraneoplastic neurological disorders are relatively rare conditions posing both diagnostic as well as therapeutic challenges. A previously fit 66-year-old woman presented with subtle cerebellar symptoms which progressed rapidly over the course of days. Chest x-ray and routine blood tests were unremarkable. CT of the head with contrast showed no abnormality. Lumbar puncture showed no evidence of infection or oligoclonal bands. She was transferred to a neurological centre from a remote and rural setting. Subsequent MRI was reported to be normal as well. Tumour markers were negative but the paraneoplastic anti-Yo antibody was positive. A whole body CT scan revealed a spiculated left breast lesion which turned out to be malignant on fine needle aspiration. She underwent left mastectomy, had plasmapharesis and received high-dose intravenous Ig for her paraneoplastic neurological symptoms. She remained neurologically stable and underwent rehabilitation in her local hospital before getting discharged home.