Introduction: Although it is not rare for magnetic resonance imaging findings in Creutzfeldt-Jakob disease to be asymmetric, unilateral clinical syndromes are uncommonly reported and may confound diagnosis. In addition, neurological paraneoplastic syndromes are not common in renal cell carcinoma, though there are cases reported, often without an offending antibody isolated. Case Report: A 66-year-old man was admitted with 1 month of left-sided numbness and "loss of control" of the left arm. Examination revealed action-induced irregular jerking movements of the left arm. Mental status testing was normal. Magnetic resonance imaging brain revealed patchy areas of restricted diffusion along the cerebral cortices. Screening computed tomographic scans revealed innumerable lung nodules compatible with metastases, as well as a renal mass consistent with renal cell carcinoma. Lumbar puncture was performed and cerebrospinal fluid was sent for paraneoplastic autoantibody evaluation and protein 14-3-3. Over the next week the patient developed dystonic posturing of the left arm, left leg jerking movements, a right arm action tremor, and cognitive impairment. Paraneoplastic autoantibodies were negative. Protein 14-3-3 was elevated and brain biopsy revealed spongiform encephalopathy with positive immunoblotting. The patient died about 2 months from symptom onset. Conclusions: Creutzfeldt-Jakob disease can present with entirely unilateral myoclonus and numbness, without specific complaints of cognitive impairment. Not every difficult or unclear neurological syndrome in a patient with metastatic cancer is a paraneoplastic syndrome.
- paraneoplastic syndrome
- prion disease