label: retroperitoneal inflammatory myofibroblastic tumor
label_lc: retroperitoneal inflammatory myofibroblastic tumor
description: "A multinodular intermediate fibroblastic neoplasm arising from the retroperitoneum. It is characterized by the presence of spindle-shaped fibroblasts and myofibroblasts, and a chronic inflammatory infiltrate composed of eosinophils, lymphocytes and plasma cells."