OBJECTIVES - Meningiomas are rare in children and, unlike in adults, they have male predominance, unusual locations, cystic components and poorer clinical outcomes. The aims of our study were to: a) evaluate the MRI features of pediatric meningiomas; b) correlate ADC values of meningiomas with clinical and histopathological types; and c) correlate peritumoral edema with size and histopathological type of tumor.
PATIENTS AND METHODS - Radiological data from 24 patients (mean age: 14.3 years) with an imaging or histopathological diagnosis of meningioma, and presurgical MRI between 1995 and 2009 from two medical institutions, were reviewed. Meningiomas were clinically classified as spontaneously arising meningiomas (SAM), NF2-associated meningiomas (NF2-M) and radiation-induced meningiomas (RIM) and, histopathologically, according to the WHO classification system. The main MRI signal characteristics and enhancement were evaluated. ADC values were compared with histopathological type and clinical group. Tumor size and peritumoral edema were also assessed.
RESULTS - Thirty-four meningiomas (eight SAM, 13 NF2-M, 13 RIM) in 24 patients (12 male, 12 female) were evaluated. Unusual locations were frequently seen in SAM, including cases of intraventricular and intraparenchymal meningiomas. SAM were also always larger than either RIM or NF2-M. Cystic components were only found in SAM, and were not associated with high-grade tumors (WHO II and III). Mean ADC values were significantly different between SAM and NF2-M, but were not associated with histopathological type. Peritumoral edema correlated with tumor size, but did not differ significantly according to clinical group.
CONCLUSION - Pediatric SAM have unusual locations, larger size and cystic components, and are diagnosed at a younger age than NF2-M and RIM. NF2-M can have unusual locations such as, in particular, the craniocervical junction. Tumor ADC values did not help to predict tumor grade or clinical type. Peritumoral edema correlated with tumor size, but not with clinical group or histopathological grade.
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