Polymyoclonus, laryngospasm, and cerebellar ataxia associated with adenocarcinoma and multiple neural cation channel autoantibodies

Objective: To describe and provide audiovisual documentation of a syndrome of polymyoclonus, laryngospasm, and cerebellar ataxia associated with adenocarcinoma and multiple neural cation channel autoantibodies. Design: Case report with video. Setting: University hospitals. Patient: A 69-year-old woman presented with subacute onset of whole-body tremulousness and laryngospasm attributed to gastroesophageal reflux. Results: Further evaluation revealed polymyoclonus, cerebellar ataxia, and laryngospasm suspicious of an underlying malignant neoplasm. Surface electromyography of multiple limb muscles confirmed the presence of polymyoclonus. The patient was seropositive for P/Q-type voltage-gated calcium channel antibody; subsequently, whole-body fluorine 18 fluorodeoxyglucose positron emission tomography and cervical lymph node biopsy revealed widespread metastatic adenocarcinoma. Follow-up serologic evaluation revealed calcium channel antibodies (P/Q type and N type) and potassium channel antibody. Conclusions: We highlight the importance of recognizing polymyoclonus. To our knowledge, this is also the first description of a syndrome of polymyoclonus, laryngospasm, and ataxia associated with adenocarcinoma and these cation channel antibodies.