Resection of melanocytic nevi as a potential treatment of anti-NMDAR encephalitis patients without tumor: report of three cases

Paraneoplastic NMDA encephalitis, a case report and an extensive review of available literature

Anti-N-methyl-D-aspartate receptor (NMDAr) encephalitis is a prevalent autoimmune condition marked by diverse neuropsychiatric symptoms, primarily impacting young females. The exact mechanisms underlying the development of NMDAr encephalitis have not been fully elucidated. Nonetheless, studies have demonstrated that auto-antibodies targeting the NR1-NR2 subunits of the NMDAr can trigger receptor dysfunction within the central nervous system, thus giving rise to the associated symptoms. Notably, an association exists between NMDAr encephalitis and an underlying neoplastic condition, with approximately 38% of cases exhibiting this paraneoplastic relationship with ovarian teratomas being the most commonly associated malignancy. While the association between NMDAr encephalitis and renal cell carcinoma (RCC) is exceedingly rare. This case report presents the clinical scenario of a 20-year-old female patient diagnosed with NMDAr encephalitis in conjunction with RCC discovered incidentally on a CT abdomen and pelvis performed to rule out an ovarian teratoma. The presented case underscores the importance of adopting a multidisciplinary approach in the diagnosis and treatment of NMDAr encephalitis, particularly when it is linked to an underlying malignancy. Furthermore, it emphasizes the significance of expanding our understanding of the molecular pathogenesis of NMDAr encephalitis to enhance patient care and optimize clinical outcomes. Additionally, a comprehensive review of the existing literature is included, summarizing all reported malignancies associated with NMDAr encephalitis.

Surgical outcomes in patients with anti-N-methyl D-aspartate receptor encephalitis with ovarian teratoma

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is an autoimmune encephalitis mediated by anti-N-methyl-D-aspartate receptor antibodies. Ovarian teratoma is closely related to anti-N-methyl-D-aspartate receptor encephalitis. However, the optimal treatment remains unknown, and strategies used for the diagnosis and therapy, including surgical intervention of ovarian teratoma, are debatable.

OBJECTIVE

The objective of the study was to study the clinical features of anti-N-methyl-D-aspartate receptor encephalitis with ovarian teratoma to further understand the disease.

STUDY DESIGN

This single-center prospective study included patients with anti-NMDAR encephalitis with ovarian teratoma from 2011 to 2016 who were admitted to Peking Union Medical College Hospital, Beijing, and discussed the clinical characteristics, treatment, and prognosis of the disease. The diagnosis of anti-N-methyl-D-aspartate receptor encephalitis was established preoperatively by identifying anti-N-methyl-D-aspartate receptor antibodies in the cerebrospinal fluid. Ovarian teratomas were suspected preoperatively by pelvic ultrasound and were diagnosed pathologically after laparoscopic detection and ovarian tumor resection. All patients were treated with first-line immunotherapy (steroids, intravenous immunoglobulin, and plasmapheresis), and when the therapy failed, they were treated with second-line immunotherapy (cyclophosphamide and rituximab). All patients were followed up regularly, and N-methyl-D-aspartate receptor antibodies, pelvic ultrasound, and neurological condition were monitored. Neurological symptoms were assessed using the modified Rankin Scale.

RESULTS

A total of 108 female patients with anti-N-methyl-D-aspartate receptor encephalitis were screened, of whom, 29 patients (26.9% of 108; mean age ± SD, 23.14 ± 6.59 years) had pathologically confirmed ovarian teratoma. The incidence of fever, decreased consciousness, arrhythmia, central hypoventilation, ventilator-assisted respiration, and intensive unit care (75.9%, 65.5%, 27.6%, 55.2%, 55.2%, and 58.6%, respectively) were significantly higher in patients with ovarian teratoma than in those without ovarian teratoma. The modified Rankin Scale at the acute onset in those 29 patients was 4.11 ± 1.20, which was also much higher than that in patients without ovarian teratoma (3.58 ± 1.08). Of the 29 patients with ovarian teratoma, 22 (75.9%) underwent laparoscopy during the acute onset of neurological symptoms. The mean diameter of the tumor was 4.61 ± 3.41 cm (SD), and the smallest tumor was only 1 cm in the unilateral ovary. All other cysts, except 4 bilateral cysts (13.8%), were unilateral. Only 1 patient was diagnosed pathologically with immature ovarian teratoma, while others had benign ovarian teratomas. In all, 28 patients (96.5%) had a good outcome (modified Rankin Scale ≤2) and 1 died. In the follow-up visit (mean duration, 37.69 months), the relapse rate of encephalitis in patients with ovarian teratoma undergoing laparoscopic cystectomy was 14.6%, whereas for those without ovarian teratoma, the relapse rate was 33.3%. The removal of ovarian teratoma was associated with reduced risk of relapse.

CONCLUSION

Patients having anti-N-methyl-D-aspartate receptor encephalitis with ovarian teratomas tend to present more severe neurological conditions. The diameter of the tumor in these patients is not very large and could be as small as 1 cm, and thus, careful exploration should be considered during surgery. Most of the ovarian teratomas in patients with anti-N-methyl-D-aspartate receptor encephalitis are mature. Early operative treatment is safe and effective because it is associated with reduced risk of relapse and complete recovery.

Coexistence of Autoimmune Encephalitis and Other Systemic Autoimmune Diseases

Background: In recent years, the phenomenon of coexisting systemic autoimmune diseases (ADs) in patients with autoimmune encephalitis (AE) has been increasingly found, while its clinical significance remains unexplored. This study aimed to investigate the types and potential clinical associations of autoimmune comorbidities in patients with antibody-positive AE.

Methods: A retrospective cohort study of patients with antibody-positive AE was conducted from 2011 to 2018. The demographics, clinical characteristics, and follow-up data were reviewed.

Results: We enrolled 517 patients, among whom 45 were affected by one or more types of ADs, including Hashimoto's thyroiditis (HT) (n = 28), systemic lupus erythematosus (SLE) (n = 3), anaphylactoid purpura (n = 3), vitiligo (n = 3), Sjögren's syndrome (SS) (n = 2), chronic urticaria (n = 2), bullous pemphigoid (n = 1), uveitis (n = 1), myasthenia gravis (MG) (n = 1), and the coexistence of SLE and anaphylactoid purpura (n = 1). The proportion of patients with coexisting ADs was higher in those with anti–leucine-rich glioma-inactivated 1 (LGI1) encephalitis than in those with anti–N-methyl-d-aspartate receptor (NMDAR) encephalitis (13/111 vs. 16/307) (P = 0.021). In anti-NMDAR and anti-LGI1 encephalitis patients, there were no significant differences in the age at onset, sex ratio, proportion of patients with tumors, disease severity, or recurrence between the groups with and without ADs.

Conclusions: One or more types of ADs developed in AE patients, and patients with anti-LGI1 encephalitis had a higher frequency of autoimmune comorbidities than those with anti-NMDAR encephalitis. And we found that autoimmune comorbidities did not affect the clinical course of AE.

Anti-NMDAR encephalitis: A single-center, longitudinal study in China

OBJECTIVE

To describe the detailed clinical characteristics, immunotherapy, and long-term outcomes of patients with anti-NMDA receptor (NMDAR) encephalitis in China.

METHODS

A single-center, prospective study. Patients who met the diagnostic criteria were enrolled from 2011 to 2017 and followed up. The clinical features, treatment, and long-term outcomes were collected prospectively. Factors affecting the long-term prognosis were analyzed.

RESULTS

The study included 220 patients. The most common clinical presentations were psychosis (82.7%) and seizures (80.9%). Of the patients, 19.5% had an underlying neoplasm; of which ovarian teratoma was 100% of tumors in females and only one male had lung cancer. Most patients (99.5%) received first-line therapy (glucocorticoids, IV immunoglobulin, or plasmapheresis alone or combined), and only 7.3% received second-line immunotherapy (rituximab, cyclophosphamide alone, or combined). Long-term immunotherapy (mycophenolate mofetil or azathioprine >1 year) was administered to 53.2% of patients. During the first 12 months, 207 (94.1%) patients experienced improvement, and 5 (2.3%) died, whereas 38 (17.3%) experienced relapses. At 12-month follow-up, 92.7% had favorable clinical outcomes (modified Rankin Scale score ≤2).

CONCLUSIONS

Patients in China present with psychosis and seizure frequently but have a low percentage of underlying neoplasms. Re-enforced first-line immunotherapy is effective in managing anti-NMDAR encephalitis in the acute phase. Although relapse is relatively common, with combined first-line and long-term immunotherapy, most patients reached favorable outcomes.