NIMG-19NEURORADIOLOGIC CHARACTERISTICS OF ASTROBLASTOMA: A META-ANALYSIS BASED ON 127 PATIENTS IN 59 PUBLICATIONS

BACKGROUND AND AIMS: Astroblastoma is a rare tumor of uncertain origin most commonly presenting in the cerebral hemispheres of children and young adults. The literature has a few case reports and series regarding its radiologic features. This meta-analysis is the largest review of imaging findings to date and serves to differentiate astroblastoma from other neoplasms. METHODS: A PubMed search identified reports of astroblastoma with neuroimaging findings. Data collected included patient age, sex, tumor location, morphology, calcifications, calvarial changes and findings on computed tomography (CT) and magnetic resonance imaging (MRI), including diffusion weighted imaging (DWI). RESULTS: Patient age range at diagnosis was 0-70 years (mean 18 years; median 14 years) with a female:male ratio of 8:1. Of 127 cases, 65 reported CT, 78 reported MRI and 47 reported both CT and MRI findings. Tumor location was supratentorial in 96% (122/127), superficial in 71% (47/66), well-demarcated in 96% (79/82), cystic-solid in 93% (79/85), and enhancing in 99% (77/78). On CT, 84% (26/31) of astroblastomas were hyperattenuated. Calcifications were present in 77% (27/35), with five cases also reporting adjacent calvarial erosion. Astroblastomas were hypointense on T1 in 58% (25/43) and hypointense on T2 in 50% (23/46). Peritumoral edema was present in 79% (38/48) of cases, but typically described as slight. Few cases reported DWI sequences, with 100% (4/4) showing hyperintensity and decreased ADC values indicating restricted diffusion. CONCLUSION: Most astroblastomas occur in young females. 96%, 71%, 96%, 93%, 99% are supratentorial, superficial, well-defined, cystic-solid, and enhancing, respectively. On CT, most are hyperattenuated, have calcifications, and if superficial, may erode adjacent bone. On MRI, astroblastomas are characteristically dark on both T1 and T2 with 100% of cases showing restricted diffusion on DWI.