Childhood Medulloblastoma Revisited.

Medulloblastoma is the most common malignant solid tumor in childhood and the most common embryonal neuroepithelial tumor of the central nervous system. Several morphological variants are recognized: classic medulloblastoma, large cell/anaplastic medulloblastoma, desmoplastic/nodular medulloblastoma, and medulloblastoma with extensive nodularity. Recent advances in transcriptome and methylome profiling of these tumors led to a molecular classification that includes 4 major genetically defined groups. Accordingly, the 2016 revision of the World Health Organization's Classification of Tumors of the Central Nervous System recognizes the following medulloblastoma entities: Wingless (WNT)-activated, Sonic hedgehog (SHH)-activated, Group 3, and Group 4. This transcriptionally driven classification constitutes the basis of new risk stratification schemes applied to current therapeutic clinical trials. Because additional layers of molecular tumor heterogeneities are being progressively unveiled, several clinically relevant subgroups within the 4 major groups have already been identified. The purpose of this article is to review the recent basic science and clinical advances in the understanding of "medulloblastomas," and their diagnostic imaging correlates and the implications of those on current neuroimaging practice.

Pectus deformities: tomographic analysis and clinical correlation.

OBJECTIVE: To assess, with computed tomography (CT) studies, features of anterior chest wall development that can be related to different types of pectus deformities. MATERIALS AND METHODS: From 71 patients with pectus deformities and chest coronal CT scans, 48 (40 male and 8 female), with a mean age of 15.8 years (ranging from 5 years to 38.4 years) were selected and divided into five groups, according to clinical type of deformity and image quality. A similar CT study was performed in a sixth group of 14 individuals with no underlying pectus deformity (control group), six male and eight female, mean age 19.3 years, (range 10.8 years to 30.5 years), totaling 62 subjects. Tomographic studies were performed on a 64-section CT scanner, with parameters varied according to the subject's body mass index (BMI). Coronal reconstructions were used to assess six features of the sternum and costal cartilages in the groups. Two other factors, a sternal index, created to estimate the sternal body width, and the sternocostal angles, were also studied. RESULTS: Feature I was noted in 13 patients and in no controls (P = 0.002), feature II in 39 patients and in one control (P = 0.000), feature III in 37 patients and in two controls (P = 0.002), and feature IV in two patients and in no controls (P = 0.002). The sternal index was significant to one group of patients. CONCLUSION: The features studied and the index provide measurable and applicable data for the interpretation of anterior chest wall tomography, with possible implications for prognosis and treatment of different types of pectus deformities.