A Case of Paraneoplastic Stiff-Person Syndrome Associated with Breast Cancer

ABSTRACT

Stiff-person syndrome (SPS) is a rare CNS disease characterized by progressive fluctuating rigidity and superimposed muscle spasms. We report a woman who developed stiff-person syndrome in association with breast cancer. A 55-year-old woman had progressive rigidity and intermittent muscle spasms, which predominantly occurred in her right shoulder muscles. Her symptoms were aggravated by unexpected stimuli or emotional stress, but relieved during sleep. Needle electromyography showed continuous motor unit activities in affected muscles, which were completely abolished by general anesthesia. An Anti-GAD antibody test was negative. She also disclosed a subacute sensory neuronopathy, confirmed by nerve conduction study and sural nerve biopsy. Chest CT scan revealed an enlargement of the right axillary lymph node, which was proved to be a metastatic ductal carcinoma of the right breast. The authors report the first case of paraneoplastic stiff-person syndrome with sensory neuropathy of axonal type, which is associated with breast cancer.