Pediatric paraneoplastic neuromyelitis optica spectrum disorder associated with ovarian teratoma

Neuromyelitis optica spectrum disorders associated with AQP4-positive-cancer—A case series

Neuromyelitis optica spectrum disorders (NMOSD) are autoimmune, astrocytopathic diseases affecting the central nervous system(CNS), especially the central optic nerve and spinal cord. Aquaporin 4-immunoglobulin G (AQP4-IgG) is the dominant pathogenic antibody and can be detected in about 80% of patients with NMOSD. Although only a few cases were reported on NMOSD associated with cancer, they demonstrated the potential paraneoplastic link between cancer and NMOSD. In the present study, we report three NMOSD cases associated with cancer, which are teratoma and lung adenocarcinoma, teratoma, and transverse colon adenocarcinoma, respectively. Pathological staining of tumor sections revealed a high AQP4 expression. After tumor removal, all cases were stable and suffered no further relapses, which revealed the potential paraneoplastic mechanism between cancer and NMOSD. One of our patient's serum AQP4-IgG was transiently slightly elevated even though AQP4 was highly expressed in tumor cells, which indicates that AQP4 is not the main pathogenic antibody but might be induced by other underlying pathogenic antibody–antigen reactions.

Investigating paraneoplastic aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorder through a data-driven approach

BACKGROUND

Aquaporin-4 IgG seropositive neuromyelitis optica spectrum disorder (AQP4-IgG NMOSD) might occur in association with cancer. According to diagnostic criteria, a probable paraneoplastic NMOSD can be diagnosed only in patients with isolated myelitis and adenocarcinoma or tumors expressing AQP4. The aim of this study was to explore the features of paraneoplastic NMOSD through a data-driven approach.

METHODS

A systematic literature review was performed. Patients with AQP4-IgG positivity in association with tumor in the absence of history of checkpoint inhibitors administration/central nervous system metastases were included. Demographic, clinical, and oncological data were collected. A hierarchical cluster analysis (HCA) was performed and data were compared between resulting clusters.

RESULTS

A total of 1333 records were screened; 46 studies (72 patients) fulfilled inclusion criteria. Median age was 54 (14-87) years; adenocarcinoma occurred in 41.7% of patients, and 44% of cases had multifocal index events. Cancer and NMOSD usually co-occurred. HCA classified patients in three clusters that differed in terms of isolated/multifocal attacks, optic neuritis, pediatric onset, and type of underlying tumor. Age, time from neoplasm to NMOSD onset, and tumor AQP4 staining did not differ between clusters.

CONCLUSIONS

Our data-driven approach reveals that paraneoplastic NMOSD does not present a homogeneous phenotype nor peculiar features. Accordingly, cancer screening may be useful in AQP4-IgG NMOSD regardless of age and clinical presentation.

Ovarian Teratoma-Related Paraneoplastic Neurological Syndromes

Paraneoplastic neurological syndromes (PNSs) are a group of neurological disorders triggered by an underlying remote tumor. Ovarian teratoma (OT) is the most common histologic type of germ cell tumor in females. The most common PNSs associated with OT is anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. However, with the increasing number of new antibodies reported over the last decade, the clinical spectrum of OT-related PNSs is also expanding. Our knowledge of OT-related PNSs is still far from complete. Here, we provide a comprehensive review of the most recent findings in the field of OT-related PNSs, with a particular focus on their clinical and pathological characteristics. Overall, the description of neuronal antibodies in PNSs associated with OT strongly suggests that antibodies may be responsible for the clinical symptoms in some cases. OT-related PNSs are associated with various clinical manifestations, including anti-NMDAR encephalitis, limbic encephalitis, encephalomyelitis, progressive cerebellar syndrome and opsoclonus-myoclonus syndrome. The pathological characteristics of the OT suggest that the mechanism of PNSs is probably due to heteromorphic neurons in the tumor tissue, the ectopic expression of the antigens in neural tissue within the teratomas and patients' unusual immune response. Despite the severity of the neurological syndromes, most patients with OT-related PNSs showed good neurologic response to early tumor resection combined with immunotherapy. To further advance the management of OT-related PNSs, additional studies are needed to explore this complex topic.