A Rare Case of Paraneoplastic Encephalitis Induced by Ovarian Dermoid

Background: Paraneoplastic encephalomyelitis is a subgroup of paraneoplastic neurological syndromes, a collection of neurological symptoms linked with cancer-related antibodies against neuronal proteins. Because it has been identified lately and has not been reported in many places, it is easily ignored or missed. Young women with teratomas may have psychiatric symptoms and behavioral abnormalities. Case Presentation: We present a case of a 41-years-old female with abnormal movements and psychotic behavior. She was initially diagnosed with an acute psychotic episode. After further investigations, she was admitted to the ICU and treated for CNS infection. She did not show any response to treatment. We suspected paraneoplastic limbic encephalitis after MRI and contrast CT showed an adnexal dermoid cyst. She did not improve with IV steroids as a resolution of symptoms only happened after surgical intervention with cystectomy and salpingooophorectomy. Conclusion: Dermoid cystic teratoma is rarely complicated by the paraneoplastic syndrome. Current medical practice does not indicate screening for anti-NMDAR antibodies in teratoma patients. Despite that, regarding teratomas, we recommend suspecting paraneoplastic syndrome when dealing with deteriorated cognitive and behavioral signs in a young woman. Furthermore, it's vital to exclude an ovarian tumor with clinical examination and radiological imaging in young women with neurological syndromes, particularly those of the reproductive age group.