[Clinical and prognostic analysis of opsoclonus-myoclonus-ataxia syndrome in children].

Objective: To summarize the clinical and prognostic features of children with opsoclonus-myoclonus-ataxia syndrome (OMAS). Methods: A total of 46 patients who met the diagnostic criteria of OMAS in the Department of Neurology, Beijing Children's Hospital from June 2015 to June 2023 were retrospectively analyzed. Centralized online consultations or telephone visits were conducted between June and August 2023. The data of the children during hospitalization and follow-up were collected, including clinical manifestations, assistant examination, treatment and prognosis. According to the presence or absence of tumor, the patients were divided into two groups. The chi-square test or Mann-Whitney U test was used to compare the differences between the two groups. Univariate Logistic regression was used to analyze the factors related to OMAS recurrence and prognosis. Results: There were 46 patients, with 25 males and the onset age of 1.5 (1.2, 2.4) years. Twenty-six (57%) patients were diagnosed with neuroblastoma during the course of the disease, and no patients were categorized into the high-risk group. A total of 36 patients (78%) were followed up for≥6 months, and all of them were treated with first-line therapy with glucocorticoids, gammaglobulin and (or) adrenocorticotrophic hormone. Among the 36 patients, 9 patients (25%) were treated with second-line therapy for ≥3 months, including rituximab or cyclophosphamide, and 17 patients (47%) received chemotherapy related to neuroblastoma. At the follow-up time of 4.2 (2.2, 5.5) years, 10 patients (28%) had relapsed of OMAS. The Mitchell and Pike OMS rating scale score at the final follow-up was 0.5 (0, 2.0). Seven patients (19%) were mildly cognitively behind their peers and 6 patients (17%) were severely behind. Only 1 patient had tumor recurrence during follow-up. The history of vaccination or infection before onset was more common in the non-tumor group than in the tumor group (55%(11/20) vs. 23%(6/26), χ²=4.95, P=0.026). Myoclonus occurred more frequently in the non-tumor group (40%(8/20) vs. 4%(1/26), χ²=7.23, P=0.007) as the onset symptom. Univariate Logistic regression analysis showed that the tumor group had less recurrence (OR=0.19 (0.04-0.93), P=0.041). The use of second-line therapy or chemotherapy within 6 months of the disease course had a better prognosis (OR=11.64 (1.27-106.72), P=0.030). Conclusions: OMAS in children mostly starts in early childhood, and about half are combined with neuroblastoma. Neuroblastoma in combination with OMAS usually has a low risk classification and good prognosis. When comparing patients with OMAS with and without tumors, the latter have a more common infection or vaccination triggers, and myoclonus, as the onset symptom, is more common. Early addition of second-line therapy is associated with better prognosis in OMAS.

[Expression of programmed cell death ligand 1 and clinicopathological and immunological characteristics in fumarate hydratase-deficient renal cell carcinoma].

Objective: To investigate the expression of programmed cell death ligand 1 (PD-L1), clinicopathologic features, immunohistochemical expression and molecular characteristics in fumarate hydratase (FH)-deficient renal cell carcinoma and to explore the potential application of immunotherapy in the patients. Methods: There were six patients with FH-deficient renal cell carcinoma treated at the First Affiliated Hospital of Fujian Medical University between January 2020 and October 2022. The clinical data, histological morphology, immunophenotype, PD-L1 expression and next-generation sequencing results were tabulated and analyzed. Results: There were 6 patients, all male, age ranged from 37 to 72 years (mean 45.7 years). Four cases were high-grade (WHO/ISUP grade3-4) with 2 or more histologic patterns, including papillary (most common), glandular, tubular, vesicular, ethmoid, nest-like, cystic and solid structures. Two cases were low-grade which showed nest-like, glandular, or tubular arrangement with eosinophilic flocculent cytoplasm and small intracellular vacuoles. Immunohistochemical analysis revealed strong expression of 2SC in all 6 cases, negative expression of FH in 5 cases, and positive expression of GATA3 in 5 cases. In high-grade cases, the mean values of CD4 and CD8 positive T-lymphocytes in advanced tumor invasion were 180.3/mm2 and 130.5/mm2, respectively. PD-L1 combined positive scores (CPS) were 20, 50, 5 and 30, respectively. The Ki-67 proliferative index were 20%, 20%, 10% and 30%, respectively. In low-grade cases, the mean values of CD4 and CD8 positive T-lymphocytes were 123.0/mm2 and 100.5/mm2, respectively. The PD-L1 CPS score was 1, and the Ki-67 proliferation index was 3%. High-throughput sequencing showed FH gene somatic mutation in 3 cases, FH gene germline mutation in 2 cases, and FH gene mutation was not detected in one case. Conclusion: FH-deficient renal cell carcinoma is more commonly high-grade than low grade. FH and 2SC are immunohistochemical markers used in the diagnosis of FH-deficient renal cell carcinoma, and GATA3 positivity is supportive of the diagnosis. The tumor infiltration of high-grade FH-deficient renal cell carcinoma shows an increase in CD4 and CD8 positive T-lymphocytes, and high expression of PD-L1; thus, anti-PD-L1 immunotherapy can be used as a treatment option.

[Clinical observation on the overlapping syndrome of myelin oligodendrocyte glycoprotein antibody and anti-N-methyl-D aspartate receptor in children].

Objective: To investigate the clinical features, imaging findings and prognosis of children with overlapping syndrome of myelin oligodendrocyte glycoprotein (MOG) antibody disease and anti-N-methyl-D aspartate receptor (NMDAR) encephalitis (MNOS). Methods: The clinical manifestations, immunological antibodies in blood and cerebrospinal fluid, cranial image, treatment and follow-up of 11 patients diagnosed as MNOS in the Department of Neurology, Beijing Children's Hospital from January 2011 to April 2019 were analyzed retrospectively. Results: A total of 11 patients, including 4 males and 7 females were analyzed, the age of onset was (10.4±2.3) years. A total of 29 episodes occurred in 11 children. At the last follow-up, 8 cases showed relapsed remission course, the interval of recurrence was 3 to 60 months. The onset symptoms of 11 patients included convulsions (10 cases), lethargy (6 cases), psychosis (6 cases). Among 29 episodes, the common symptoms were convulsions (16 episodes), psychosis (13 episodes),and lethargy (10 episodes). According to the diagnostic criteria of anti-NMDAR encephalitis and MOG-antibody disease, 29 episodes were divided into three phenotypes, including anti-NMDAR encephalitis(4 episodes), MOG-antibody diseases (10 episodes) and overlapping types (15 episodes).Twenty-seven times of acute stage cranial magnetic resonance imaging (MRI) were available, common lesions included cortical focus (22 times), subcortical white matter (7 times), brainstem (9 times). All patients were sensitive to first-line immunotherapy. Eight patients had recurrence during glucocorticoid reduction, 6 of them were treated with additional second-line immunosuppressive therapy, including cyclophosphamide (1 case) and mycophenolate mofetil (5 cases). The follow-up time of patients were 5-99 months. At the last follow-up, all patients were in remission, the pediatric cerebral performance category (PCPC) score was 1 (10 cases) and 2 (1 cases). Conclusions: MNOS mainly affects older children. In the period of acute episodes, convulsions and psychosis are common. The cranial MRI showed extensive brain involvement and mainly in the cortex. The recurrence rates of MNOS are relatively high, patients are sensitive to first-line immunotherapy. No significant neurological dysfunction was left in the remission stage.

[Primary skull base chondrosarcoma: a clinicopathological analysis].

Objective: To investigate the clinicopathological features, immunophenotype, molecular characteristics and differential diagnosis of primary skull base chondrosarcoma. Methods: Nine cases of primary skull base chondrosarcoma were collected at the First Affiliated Hospital of Fujian Medical University, from January 2006 to June 2019, reviewed for the clinical and radiologic data and morphologic features, immunophenotype and molecular characteristics. Results: Among all the 9 cases, six were male, three were frmale, with average age 47 years, and median age 47 years; five cases were WHO gradeⅠ, and four were WHO grade Ⅱ. Microscopically, the tumor showed lobulated growth pattern with low-medium cellularity within a chondroid or mucoid background. The tumor cells showed mild-moderate atypia, with binucleated forms, and mitosis was rare or occasional. Immunohistochemistry (IHC) showed tumor cells were positive for S-100 protein, vimentin, SOX-9 and D2-40, and negative for Brachyury, CK, EMA and CK8/18; the Ki-67 index was low (1% to 5%). Molecular analysis showed IDH1 R132C mutation in four cases. Conclusions: Skull base chondrosarcoma is a rare cartilaginous malignant tumor with a good prognosis. Its characteristic morphologies, combined with IHC and molecular detection are helpful for the differential diagnosis.

[Progressive cavitating leukoencephalopathy: four cases and literatures review].

Objective: To analyze the clinical and genetic features of progressive cavitating leukoencephalopathy (PCL). Method: The data of clinical and genetic features of 4 PCL patients diagnosed by Beijing Children's Hospital between January 2015 and January 2016 were analyzed. The cases with complete clinical data retrieved on literature search at China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and PubMed (up to August 2016) by using search terms of"NDUFV1" ,"NDUFS1" , or"leukoencephalopathy" , were summarized. Result: There were three females and one male, two of which were compatriots. The age of onset ranged from 6 months to 15 months. All four children's first symptoms were motor development regression, and the developmental milestones were almost normal before the onset. Of the 4 patients, 3 had cognitive impairment, 1 had seizures, 4 had dystonia and pyramidal impairment, 2 had emaciation, and 1 had nystagmus. The lactate concentrations of 4 patients were normal in blood. One patient had lactaciduria in the urinary organic acid analysis. Cranial magnetic resonance imaging (MRI) of all patients showed leukoencephalopathy, involved in the corpus callosum, and three patients accompanied by cystic lesions. Follow up for 2-13 years showed that the physical and language development were improved. Genetic analysis revealed that mutations in NDUFS1 were found in three patients and NDUFV1 mutation was found in one patient. All six mutations (p.Arg377Cys and p. Arg377His in NDUFV1; p. Arg482Glyfs(*)5, p.Thr368Pro, p.Tyr454X and p. Asp565Gly in NDUFS1) are novel. Five English case reports including 10 PCL patients were collected. Together with this group of 4 cases, a total of 14 cases were involved. All 14 children patients had motor development regression, 11 cases had cognitive impairment and dystonia, 6 cases had pyramidal impairment, 5 cases had irritability, 4 cases had epilepsy and nystagmus, 3 cases had strabismus and swallowing difficulty. Cranial MRI showed patchy leukoencephalopathy with cavities, involved in the corpus callosum. Follow up for 19 months-15 years that the neurology development were improved slowly in all patients. Conclusion: NDUFS1 and NDUFV1 gene mutation screening should be performed firstly in patients with PCL clinical and imaging feature.