ABSTRACT
Medulloblastoma is the most common malignant pediatric brain tumor. Medulloblastoma should not be viewed as a single disease, but as a heterogeneous mixture of various subgroups with distinct characteristics. Based on genomic profiles, four distinct molecular subgroups are identified: Wingless (WNT), Sonic Hedgehog (SHH), Group 3 and Group 4. Each of these subgroups are associated with specific genetic aberrations, typical age of onset as well as survival prognosis. Magnetic resonance imaging (MRI) is performed for all patients with brain tumors, and has a key role in the diagnosis, surgical guidance and follow up of patients with medulloblastoma. Several studies indicate MRI as a promising tool for early detection of medulloblastoma subgroups. The early identification of the subgroup can influence the extent of surgical resection, radiotherapy and chemotherapy targeted treatments. In this article, we review the state of the art in MRI-facilitated medulloblastoma subgrouping, with a summary of the main MRI features in medulloblastoma and a brief discussion on molecular characterization of medulloblastoma subgroups. The main focus of the article is MRI features that correlate with medulloblastoma subtypes, as well as features suggestive of molecular subgroups. Finally, we briefly discuss the latest trends in MRI studies and latest developments in molecular characterization.
ABSTRACT
To investigate associations between infections and acute monoarthritis, we performed a prospective study on 32 children consecutively hospitalized and 32 age-matched controls. Among 26 (81%) children having infections, the most frequent agents were Group A ?-hemolytic Streptococcus (GAS: 53%) and Epstein-Barr virus (EBV: 37.5%). Among controls, only 5 (16%) were infected with GAS and 2 (6%) with EBV (P<0.005). The most frequently involved joints were hip in 15 children and ankle in 10 children. Our study showed that acute monoarthritis in children may be frequently associated with streptococcal or EBV infections.