The trouble with plasma cells

Imagine: 15 years ago, a young woman is brought to your emergency room because of a series of seizures. She has a few days' history of amnesia, delusions, and hallucinations. Diagnostic workup reveals no focal neurologic deficits, MRI is normal, and CSF shows mild pleocytosis. An extensive search for infectious agents and systemic cancer proves negative. Over the next 2 weeks, the patient remains agitated and evolves to a coma with autonomic instability, continuous orofacial dyskinesias, and limb choreoathetosis. No cause is identified. Perhaps the more fortunate patient receives a short course of high-dose steroids from a diagnostically destitute clinician, or more likely no immunotherapies are commenced. Of course, nowadays, neurologists immediately consider requesting NMDA receptor (NMDAR) antibodies. This syndrome was first described in 2007 as a paraneoplastic ovarian teratoma–associated syndrome.1 It was then reported in children, men, and even elderly people,2,3 surpassing the incidence of infectious agents in young people.4