Paraneoplastic stiff-person syndrome with lung cancer: a case report and literature review.

Stiff person syndrome is a rare autoimmune disease of the central nervous system that manifests as stiffness and painful spasms of the trunk axis and lower limb muscles. Benzodiazepines are the first choice for the clinical treatment of the disease. We reported a case of SPS. The patient presented with stiffness and convulsions of lower limbs, weakness after convulsions, falling off easily, abdominal muscle stiffness, and painful spasms lasting for several minutes and alleviating spontaneously. This was caused or aggravated by fatigue or mental stimulation. Left stiffness and weakness of the muscle after relief was present. A chest-enhanced computed tomography scan (CT) suggested two large ground glass nodules in the upper lobe of the left lung. Biopsy pathology indicated the nodules as adenocarcinoma in situ. The patient's symptoms were significantly relieved after treatment with clonazepam and diazepam combined with pregabalin. The clinical manifestations of SPS vary among patients. The symptoms of the disease are mild or severe. Early identification and treatment can improve the prognoses of these patients.