Objective: Anti-N-methyl D-aspartate receptor (NMDAR) encephalitis is a paraneoplastic, immunemediated encephalopathy with a known association with ovarian tumors, more frequently with mature
teratoma.
Case Report: We present the case of a 20-year-old patient presenting with fever for 3 weeks and an acute
onset of cognitive disturbances. The initial suspicion was that of an infective encephalopathy; however, the
lumbar puncture results were negative. Electroencephalography reported epileptiform activity in anterior
horns, supporting a diagnosis of encephalopathy. Extensive autoimmune screening was done and found to
be positive for anti-NMDAR antibodies. A whole body-TC found a right adnexal tumor compatible with
ovarian teratoma. At laparoscopy, the right adnexal tumor was excised, preserving most of the ovarian
parenchyma; and histology confirmed a mature teratoma with neural tissue. There were no postoperative
complications. The patient recovered normal speech and her former cognitive status, within 40 days from
the day after surgery.
Conclusion: The association ovarian teratoma-anti-NMDAR encephalitis is a serious and potentially fatal
pathology occurring in young women and under-recognized in many countries and among gynaecologists.
Given the recent discovery, special attention should be given to possible behavioural changes and
psychiatric symptoms that may occur in young women with apparently unknown cause. It is also very
important the diagnostic confirmation through the positivity of the anti-NMDAR antibodies, the diagnosis
of the underlying tumour and the early tumour excision; since, the earlier the treatment is, the greater is the
rate of success and the clinical remission.
Malignant Transformation of a Mature Ovarian Teratoma: A Case Report and Review of the Literature
