symposium on case study ppt课件.ppt

Symposium on Case Study Department of Radiology, the second affiliated hospital of Sun yat-sen university Duan Xiao-hui Biopsy Pathology: seminoma with syneytiotrophoblast（精原细胞合并合体滋养细胞） seminoma Primary extragonadal（性腺外的） seminoma of the retroperitoneum are rarely and without specific radiologic findings. 1. Determining tumor location characterizing the retroperitoneal space identifying the organ of origin 2. Recognizing specific features of various retroperitoneal tumors evaluating patterns of spread tumor components vascularity specific signs First step--whether the tumor is located within the retroperitoneal space? The displacement of normal anatomic structures Anterior displacement of retroperitoneal organs (eg, kidneys, adrenal glands, ureters, ascending and descending colon,pancreas, portions of the duodenum) . Displacement of major vessels and some of their branches. Second step--whether the tumor originates from a retroperitoneal organ？ Identification of the organ of origin beak sign鸟嘴征 phantom (invisible) organ sign器官无形征 embedded organ sign器官包埋征 prominent feeding artery sign重要供血动脉征 1. beak sign鸟嘴征 when a mass deforms the edge of an adjacent organ into a “beak” shape, it is likely that the mass arises from that organ (beak sign) 2.phantom (invisible) organ sign 器官无形征 Large mass arises from a small organ, the organ sometimes becomes undetectable. （ phantom organ sign）. Howeer, false-positive -- huge retroperitoneal sarcomas that involve other small organs such as the adrenal gland. 3.embedded organ sign器官包埋征 part of an organ appears to be embedded in the tumor .  4.prominent feeding artery sign重要供血动脉征 Hyperascular masses are often supplied by feeding arteries. A finding that provides an important key to understanding the origin of the mass .  Third Step ：Imaging features that may narrow the differential diagnosis Recognizing specific features of various retroperitoneal tumors patterns of spread tumor components vascularity spe