Researchers in Chang Gung University, Kaohsiung, and National Cheng Kung University, Tainan, Taiwan, assessed the prevalence and spectrum of paraneoplastic neurological disorders (PND) in children with benign ovarian tumor and the long-term outcome. The charts of 133 female patients below 18 years of age diagnosed with a pathologically proven benign ovarian tumor, Jan 1993 – Dec 2010, were reviewed, mostly mature teratoma. Six patients (4.5%) had neuropsychiatric manifestations, the majority (5) with onset after age 10 years. Depression or low mood, headache, mutism, hypoventilation, seizures, hallucination, vomiting and hypersalivation were the most common symptoms. NMDAR encephalitis in 2 patients and acute disseminated encephalomyelitis in 1 partially resolved after tumor removal and immunotherapy. One patient not receiving immunotherapy had neurological sequelae and long ICU stay. 
COMMENTARY. Paraneoplastic disorders (PND) present with multiple manifestations resembling subacute encephalitis, peripheral neuropathy, cerebellar ataxia, opsoclonus myoclonus with neuroblastoma, and other symptoms. Patients with anti- NMDAR encephalitis may present with psychosis, memory deficits, seizures, speech problems, involuntary movements, and breathing disorders. Approximately 50% cases have ovarian tumors, mostly teratoma. In the present study, 5 of 6 (83%) patients with PND and ovarian teratoma had complete remission of symptoms after tumor removal. The authors recommend immunotherapy in all patients following tumor removal, despite apparent recovery after surgery .