CT characters of retroperitoneal inflammatory myofibroblastic tumor

Abstract

Objective To explore the CT characters and corresponding pathological bases of retroperitoneal inflammatory myofibroblastic tumor(IMT). Methods The CT and clinical data of 11 cases of retroperitoneal inflammatory myofibroblastic tumor proved by pathological results were analyzed retrospectively. Results Among 11 cases, 4 cases showed irregular mass, 6 lesions showed lobular configuration and 1 lesion was oval. Four lesions were located in the fatty clearance of kidney, 2 in the clearance of pancreas and stomach, 2 near the celiac aorta and 3 near the iliac vessels. The range of maximum diameter was 5.9 to 16.7 cm and the mean was 6.1 cm. On unenhanced CT, 10 tumors showed low density and 1 showed equal density. On arterial phase of the enhanced CT of 9 tumors showed moderate or vivid enhancement and 2 tumors showed mild to moderate enhancement, and on the vein phase of enhanced CT, all 11 tumors showed persistent obvious enhancement. The enhanced pattern was various: 3 cases showed solid mass with inhomogeneous enhancement, 6 cases showed solid-cystic mass with nodular, patch enhancement and some mucious degeneration, 2 tumors showed remarkable mucious degeneration with peripheral foci of enhancement. The local boundary of 9 tumors were dim and with exudation presenting as small slice or halo . Five tumors were accompanied with the thickening of adjacent peritoneum and ascites, 2 tumors infringed spleen, 4 cases infringed psoas major, 3 cases encircled the ureter of the same side and resulted in uronephrosis, 6 cases encircled adjacent blood vessels, while the boundary of the rest 2 tumors were clear relatively. Conclusions Retroperitoneal inflammatory myofibroblastic tumors show certain common characters such as huge mass with irregular shape and dim edge together with exudation of small slice or halo . The dynamic enhanced CT of different pathological types can show certain individual characters, which may be of value in the diagnosis of retroperitoneal inflammatory myofibroblastic tumor. Key words: Retroperitoneal neoplasms; Neoplasma,muscle tissue; Tomography,X-ray computed; Diagnosis