Sacrococcygeal Germ Cell Tumors: Differential Features between Benignancy and Malignancy on MR and CT Imaging

Purpose : The purpose of this study was to determine differential points between benign and malignant sacrococcygeal germ cell tumors (SGCT) on MR and CTimaging.Materials and Methods : MR (n=13) and CT images (n=9) of 19 patients with surgically-proven SG CT (12 benign , 7 malignant) were retrospectively reviewed with regard to tumor features and associated findings , as well as to clinical features including age at presentation and ratio of the sexes.Tumor features included location, size, components(ratio of the enhancing solid portion , presence of fatty components , calcification and necrosis }, signal intensity and the presence of an encircling low-s ignal rim on MR .Associated findings included the presence of sacrococcygeal bony defect and effects of the tumor on adjacent structures(anterior displacement of the bladder and rectum , local invasion).Results : Benign SGCT showed early presentation(mean age, 4.7months }, a predominantly(over half total volume) externallocation(58%) and a cystic composition(1 00%) and the presence of encircling low-signal rim on MR(80%).Malignant SGCT showed late presentation beyond infancy(mean age, 21.7months }, a predominantly internal location(86%) and a enhancing solid composition(86 %}, the presence of tumoral necrosis(71 %) and local invasion of adjacent structures(71 %).The significant(p (. 05) differential points were age at presentation , location , ratio of enhancing solid portions, the presence of tumoral necrosis, the presence of an encircling low-signal rim on MR and local invasion.Conclusion : There are certain differential points between benign and malignant SGCT on MR and CT imaging , and an appreciation of these would be helpf 비 forthe planning oftreatment.