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Background/Aims: Down syndrome is the most common inherited disorder. Some patients develop atlantoaxial instability. Existing screening guidelines were developed prior to availability of MRI. We present predictors for deficit using dynamic MRI of the craniocervical junction. Methods: A retrospective review of Down syndrome patients from 2001 to 2015 was carried out. Patients were considered symptomatic if they had clinical deficits or signal change on MRI. Measurements were taken at the atlantoaxial junction and structural abnormalities noted. Analysis was performed with SPSS. Results: A total of 36 patients were included. Patients averaged 93 months of age with a follow-up of 57 months. No asymptomatic patients developed myelopathy during follow-up. During dynamic imaging, symptomatic patients had greater changes in space available for the cord (SAC) (5.2 vs. 2.7 mm; p < 0.001) and atlantodental interval (ADI) (2.8 vs. 1.3 mm; p = 0.04). These patients were also more likely to have a bony anomaly (50 vs. 13%; p = 0.03). Conclusion: This study characterizes the range of motion seen on dynamic MRI and provides parameters that can be used to distinguish patients at risk for neurologic injury. Changes greater than 3 mm in ADI or 5 mm in SAC during dynamic MRI or any bony abnormality warrants further investigation. Patients without these features may be able to avoid an unnecessary intervention.

Introduction: Pilocytic astrocytomas (PA) are a common, benign childhood tumor known for their slow growth rates and excellent prognosis. The aim of our study was to characterize patient, tumor, and imaging-related risk factors for recurrence and progression of disease. Methods: We identified 116 patients with PA who underwent surgery at our institution between 2000 and 2015. Data were collected retrospectively from the clinical charts. Results: The mean age at resection was 7 ± 5 years (range 0.5–31) and mean follow-up was 6 ± 3 years. Initial resection was complete in 33 patients (29%), subtotal in 78 patients (67%), and biopsy in 5 patients (4%). A total of 45/116 (40%) patients experienced either recurrence or progression after initial resection with a mean time to recurrence or progression of 2.2 years. Bivariate analysis identified subtotal resection, tumor location, age at diagnosis, and imaging features (i.e., T2 invasion, exophytic component, hemorrhage, and solid tumors) as factors significantly associated with recurrence or progression (p < 0.05). Conversely, PAs that were completely resected, predominately cystic, and located in the cerebellum were significantly associated with no recurrence or progression (p < 0.05). Multivariate regression analysis narrowed down 4 robust risk factors: extent of resection, T2 invasion, predominantly solid lesions, and presence of an exophytic component (p < 0.05). Conclusion: Total surgical removal of PA has been the most important prognostic factor for the clinical course of PA. Our study reveals additional risk factors for the recurrence or progression of disease: tumor invasion, solid composition, and tumors with an exophytic component.

Background/Aims: Intracranial germ-cell tumors (GCTs) are a heterogeneous group of tumors that vary in their response to treatment. Standard treatment consists of chemotherapy and radiation therapy, with the consideration of second-look surgery in resistant disease. The present study aims to inform therapy by characterizing features on pretreatment imaging associated with recurrence. Methods: Children with intracranial GCTs treated at a single institution between January 2000 and October 2016 were retrospectively reviewed under an Institutional Review Board-approved protocol. Imaging variables identified on pretreatment imaging were calcifications, cysts, heterogeneity of enhancement, blood products, hydrocephalus, gradient echo susceptibility, restricted diffusion, invasiveness, and extent of edema. Tumor recurrence was used as the primary outcome variable. Results and Conclusion: Fifty-two patients (39 males, mean age at diagnosis: 13 ± 5 years, 34 germinoma, 18 nongerminomatous GCT [NGGCT]) were reviewed. Thirty-three percent of the patients reviewed had recurrence (7 germinoma, 11 NGGCT). Recurrence was associated with invasiveness as seen on preoperative imaging (p = 0.0385) and cystic tumor (p = 0.048).

The posterior fossa syndrome (PFS) is common after cerebellar tumor resection in pediatric patients. It is characterized by postoperative mutism and ataxia and associated with persistent abnormalities in mood and cognition. Method: A 2-year prospective study of children and adolescents with cerebellar tumors identified by neuroimaging was performed at the Children’s Hospital Los Angeles. Results: There were 8 girls and 14 boys in the study, aged 14 months to 17 years. The tumor sizes ranged from 2 to 6.5 cm in diameter. The patients presented with ataxia, headache, vomiting, depressed or irritable mood and inattention. Symptoms of PFS were present postoperatively in all except for the 2 patients with lateral tumors. The symptoms began before resection, were most prominent immediately after surgery, and improved over time. Neuropsychological assessment of 10 patients documented a persistent cognitive decrement. Conclusion: This small, descriptive study provides information on the natural history of pediatric posterior fossa tumors from before surgery through the postoperative period.

Background/Purpose: Symptomatic ventriculoperitoneal shunt (VPS) malfunction can occur without progressive ventricular dilatation on imaging studies. A review of VPS revisions performed during an 18-month period was conducted to better characterize this cohort. The incidence of VPS malfunction without ventricular dilatation and the clinical features that may predispose to its occurrence have not been previously described. Methods: A retrospective review was conducted of all patients under the age of 18 who underwent VPS revision due to shunt malfunction from June 2001 to December 2002. The incidence of various factors that might correlate with the development of low compliance ventricles was examined. Results: One hundred and seventy-seven patients underwent a total of 287 VPS revisions during the study period; 16 patients (9%) had signs of raised intracranial pressure and showed no radiographic evidence of progressive ventricular dilatation. History of prior shunt-related ventriculitis positively correlated with the development of low compliance ventricles (Fisher’s exact test, p = 0.043). Conclusion: Nine percent of pediatric patients with symptomatic VPS malfunctions lack radiographic evidence of progressive ventricular dilatation on imaging studies. Patients with prior shunt infections are particularly at risk, necessitating increased vigilance when clinical signs and symptoms are apparent.

Thirty-six cases of pilocytic astrocytomas treated at the Childrens Hospital of Los Angeles from 1984 through 1995 were reviewed. The mean age at initial presentation was 8 years (range 15 months to 14 years). These patients were followed for an average of 5.5 years. No patient was given chemotherapy or radiation therapy after the initial surgery for pilocytic astrocytoma. Twenty-three patients (64%) had a gross total resection with no residual tumor on immediate postoperative imaging studies. Three of these children had tumor recurrences 2-5 years after their initial surgery, requiring re-excision of their tumors. All 3 patients are subsequently tumor-free, with follow-up ranging from 4 to 10 years. In 4 patients with residual tumor involving the brainstem, there has been neither imaging evidence of tumor enlargement nor progression of clinical findings at 2.5, 4, 6 and 6 years, respectively. Nine of the 13 patients with residual tumor underwent re-excision, either for progression of symptoms or documented tumor growth on imaging studies. The second operation was undertaken an average of 1 year (range 1 month to 6 years) after the first. In 4 of these children (11% of our whole series), the recurrent tumor was classified as anaplastic astrocytoma. Three of these 4 children received radiation and/or chemotherapy, with only 1 patient showing disease progression in the follow-up period. Repeat blinded histopathological examination of these tumors confirmed both diagnoses. However, it was noted that 3 of the 4 pilocytic astrocytomas which subsequently showed anaplastic change initially displayed increased perivascular cellularity, while only 2 of the remaining 32 tumors exhibited this feature. These results encourage continued vigilance in the follow-up of pilocytic astrocytomas, and describe a histological feature which might indicate a more aggressive disease course.