Paraneoplastic Myoclonus with Papillary Thyroid Carcinoma

lasting 3–5 s and occurring every minute for up to 40 min. A videotape of one such spell showed frequent myoclonic jerks affecting her lower extremities more than her upper extremities. She had them occasionally while standing up, but they never caused her to fall. She did not report loss of consciousness and had no history of seizures. There was no oral trauma or urinary incontinence with these episodes. She did have a 10-year history of restless leg syndrome and was being treated with clonazepam and trazodone. When these myoclonic jerks developed, she was also started on ropinirole with modest, if any, improvement in her symptoms. The patient denied head trauma, stating that 20 years ago she had had a mild whip lash injury. She denied any family history of similar problems. An EEG with added surface EMG electrodes applied to the tibialis anterior muscle revealed multiple jerks with no associated epileptiform abnormalities. An SSEP revealed normal latencies and no giant potentials. A previously performed CT scan of the brain was normal, and MRI of the cervical and thoracic spine was ordered. It did not show any neurological abnormalities, but did find an incidental solid enhancing lesion within the right lobe of the thyroid measuring approximately 2 cm in diameter. This appeared to be a solitary nodule and further evaluation with ultrasound and biopsy revealed papillary carcinoma. She underwent complete thyroidecDear Sir, Myoclonus consists of sudden, involuntary muscular contractions [1] . The feature that distinguishes spinal, or segmental myoclonus from other forms of more generalized myoclonia is its restriction to one somatic region secondary to spinal cord pathology at the involved level [2] . Propriospinal myoclonus is characterized by generalized and symmetric jerks that arise from axial muscles and spread to other myotomes by means of propriospinal pathways [3] . Neurologic paraneoplastic disorders are syndromes that are neither due to direct metastases nor to toxicity of cancer therapy, coagulopathy, infection, or toxic/ metabolic causes. They are far less common than metastases and other nonmetastatic neurologic complications of cancer, but they are important because of the severe and permanent neurologic morbidity. Also, because often they are the presenting feature of an otherwise undiagnosed tumor, early diagnosis maximizes the likelihood of successful tumor treatment and favorable neurologic outcome [4] .