Unsuspected Ovarian Cystic Teratoma-associated Anti-NMDAR Autoimmune Encephalitis Complicated by Septic Shock, Hemophagocytic Lymphohistiocytosis, and Gastric Ischemia: Case Report

hallucinations, agitation, and insomnia.Her condition rapidly deteriorated, progressing to coma and acute respiratory failure, necessitating intensive care unit (ICU) transfer.Initial examination revealed hypoxemic-hypercapnic respiratory failure (PaO 2 62 mm Hg, PaCO 2 70 mm Hg), prompting intubation and mechanical ventilation. IntroductIonAutoimmune encephalitis (AE) is a rare, immune-mediated inflammatory condition targeting the brain parenchyma, most commonly associated with anti-N-methyl-D-aspartate receptor (anti-NMDAR) antibodies.It frequently affects young women, often in conjunction with ovarian teratomas.[1][2][3] Because ovarian teratomas may be small or initially occult, negative first-line imaging should not exclude continued tumor surveillance when clinical suspicion remains high.Patients typically present with neuropsychiatric symptoms, motor disturbances, and autonomic dysfunction.Severe cases can progress to central hypoventilation, coma, and multiorgan complications.1,4 H e m o p h a g o c y t i c l y m p h o h i s t i o c y t o s i s ( H L H ), a hyperinflammatory syndrome, is characterized by macrophage and T-cell dysregulation.Secondary HLH, seen in adults, often arises due to infections, malignancies, or autoimmune conditions.5 We present a complex case of anti-NMDAR AE in which a small ovarian cystic teratoma was identified only after repeated gynecological assessment, during a clinical course complicated by HLH, septic shock, and gastric ischemia.