Progressive encephalomyelitis with rigidity: a paraneoplastic presentation of oat cell carcinoma of the lung. Case report

Progressive encephalomyelitis with rigidity and myoclonus (PEWR) is a rare neurological disorder, characterised by muscular rigidity, painful spasms, myoclonus, and evidence of brain stem and spinal cord involvement. A 73-year-old white man was admitted with a 10-day history of painful muscle spasms and continuous muscle rigidity on his left lower limb. He had involuntary spasms on his legs and developed encephalopathy with cranial nerves signs and long tract spinal cord symptomatology. Brain CT scan and spinal MRI were normal. The CSF showed lymphocytic pleocytosis and no other abnormalities. EMG showed involuntary muscle activity with 2-6 seconds of duration, interval of 30-50 ms and a frequency of 2/second in the left lower limb. Anti-GAD antibodies were detected in the blood. We detected radiological signs of lung cancer during the follow-up, which proved to be an oat cell carcinoma. The patient died two weeks after the diagnosis of the cancer.