MRI and CT of Low-Grade Fibromyxoid Sarcoma in @entity1 : A Report From XXXX 's Oncology Group Study ARST0332.

@entity1 @entity6152 @entity5 @entity242
OBJECTIVE: The purpose of this article is to determine the MRI and CT features of low-grade @entity242 in @entity1 . MATERIALS AND METHODS: We retrospectively analyzed images of 11 pediatric @entity1 with low-grade @entity242 from a phase 3 clinical trial of nonrhabdomyosarcoma soft-tissue @entity242 ( @entity1 's Oncology Group Protocol ARST0332). MRI and CT were performed in 10 and four @entity1 , respectively. Location, size, margin, and composition on imaging were correlated with pathologic findings. RESULTS: @entity5 were located in the extremities in nine @entity1 , and one @entity5 each was located in the tongue and lung. @entity5 were deep in seven @entity1 and superficial in four @entity1 . All @entity5 were well defined, solitary, and nonmetastatic at presentation. @entity5 were complex solid-cystic in eight @entity1 and completely solid in three @entity1 . On T1-weighted images, all @entity5 had at least some areas hypointense to muscles, and six had a split-fat sign. On STIR or T2-weighted images, eight @entity5 had areas hypointense to adjacent muscle, and eight @entity5 had fluid signal intensity. On contrast-enhanced MRI studies, eight @entity5 had thick enhancing internal septations, and three had peripheral nodular gyriform enhancement. When we correlated imaging to pathologic findings, areas with hypointense signal intensity on both T1- and T2-weighted images were likely related to fibrous component; areas with fluid signal intensity on T2-weighted images were likely related to myxoid component. On CT, all four @entity5 were @entity6152 to muscle, and one @entity5 showed punctate calcific foci. CONCLUSION: Low-grade @entity242 is @entity6152 to muscle on CT. MRI may identify both fibrous and myxoid components of this rare pediatric soft-tissue @entity242 .
