Failure to improve after ovarian resection could be a marker of recurrent ovarian Teratoma in anti-NMDAR encephalitis: A case report

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a type of autoimmune encephalitis that can be paraneoplastic and usually responds to tumor resection and immu­notherapy. More than 75% of patients with anti-NMDAR encephalitis fully recover or have only mild sequelae, whereas the remainder experience severe disability. It remains unknown why certain cases have refractory clinical disease courses. We report a case of anti-NMDAR encephalitis with bilateral ovarian teratomas who was refractory to tumor resection and early initiation of immunotherapy. During intensive care, immunohistochemical analyses of her cere­brospinal fluid showed persistently high reactivity of NMDAR antibody over time. Six months after the operation, pelvic computed tomography detected a recurrent ovarian teratoma. After total enucleation of the bilateral ovaries, with significant pathological findings of bilateral mature cystic teratomas, her clinical condition improved rapidly, paralleled by a decrease in anti-NMDAR reactivity. This case illustrates the need to keep considering why extensive treatment fails to influence the disease when we encounter patients with refractory anti-NMDAR encephalitis. Failure to improve after ovarian resection could be a marker of recurrent ovarian teratoma in anti-NMDAR encephalitis.