Journal of Neuropathology and Experimental Neurology
Anti-NMDA-receptor encephalitis is a subacute, autoimmune disorder thought to be caused by autoantibodies directed against the N-methyl-D-aspartate (NMDA) receptor. Although NMDAR encephalitis is a familiar entity to psychiatrists and neurologists, it is less commonly reported in the pathology literature. Clinical symptoms of anti-NMDAR encephalitis may mimic schizophrenia and psychotic spectrum disorders or substance-induced psychosis. Although initially described in association with ovarian teratomas in women, anti-NMDAR encephalitis has been reported in individuals without paraneoplastic association, as well as in males. Previous literature has suggested NMDA receptor expressing teratoma neurons are densely aggregated and are smaller in size. Ki-67 index can be higher in these neurons and they usually show B-cell lymphocytic infiltration around them. Herein, we report a case of a 29-year-old woman with suicidal ideation and other neuropsychiatric manifestations who was found to have a right ovarian cystic mass by imaging study. Microscopically, the resected ovarian mass is composed of mature skin, fat, cartilage and neural tissues. Nerve, ganglions and multiple brain tissues are present. Interestingly, cerebellum including external granular cell layer (normally only seen in infants), cerebrum-like, choroid plexus and other neural elements are present. There is peripheral lymphoplasmacytic infiltrates around and within the neuroglial matrix. Cerebral spinal fluid tested positive for Anti-NMDAR. The combined clinical, histological, and laboratory findings confirmed the above diagnosis. Its resultant relationship to cystic teratoma warrants awareness of this condition by pathologists. Although slow to respond to treatment, this patient now continues to show improvement with plasmaphoresis. Portions of this abstract have been previously presented at the ASCP meeting in 2021.
Fatemi S, Fullmer J. Anti-NMDA-receptor encephalitis in a patient with ovarian teratoma, harboring brain histology of varying developmental stages. J Neuropathol Exp Neurol. 2022 June;81(6):466.