Associated tumors in patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis

Abstract

In 2007, Dalmau and colleagues described anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis associated with ovarian teratoma. As the numbers of patients with anti-NMDAR encephalitis increased, the frequency of paraneoplastic findings declined. The frequency of anti-NMDAR encephalitis with the tumor declined to 60% of a total of 100 patients in 2008, and 42% of a total of 400 patients in 2011. This 42% was the similar value as the tumor frequency in Acute Juvenile Female Non-Herpetic Encephalitis in Japan. It was also revealed that the discrepancies in tumor frequency of anti-NMDAR encephalitis between investigations existed. The results of stratification analyses of anti-NMDAR encephalitis revealed that patients who were younger than 18 years old and male patients with anti-NMDAR encephalitis were less likely to have associated tumors. Dalmau also reported tumors other than ovarian tumors were associated with 2% (9/400) of patients in 2011. These patients included breast cancer, neuroendocrine tumors, pancreatic carcinoma, sex cord stromal tumors, testicular germ-cell tumors and small-cell lung carcinoma. We encountered a 65-year-old female affected by anti-NMDAR encephalitis with carcinosarcoma with neuroendocrine differentiation of the uterus. The prognosis of anti-NMDAR encephalitis with malignant tumor could be dependent on the prognosis of the associated tumor.