Characterization of renal tumors is critical to determine the best therapeutic approach and improve overall patient survival. Because of increased use of high-resolution cross-sectional imaging in clinical practice, renal masses are being discovered with increased frequency. As a result, accurate imaging characterization of these lesions is more important than ever. However, because of the wide array of imaging features encountered as well as overlapping characteristics, identifying reliable imaging criteria for differentiating malignant from benign renal masses remains a challenge. Multiparametric magnetic resonance (MR) imaging based on various anatomic and functional parameters has an important role and adds diagnostic value in detection and characterization of renal masses. MR imaging may allow distinction of benign solid renal masses from several renal cell carcinoma (RCC) subtypes, potentially suggest the histologic grade of a neoplasm, and play an important role in ensuring appropriate patient management to avoid unnecessary surgery or other interventions. It is also a useful noninvasive imaging tool for patients who undergo active surveillance of renal masses and for follow-up after treatment of a renal mass. The purpose of this article is to review the characteristic MR imaging features of RCC and common benign renal masses and propose a diagnostic imaging approach to evaluation of solid renal masses using multiparametric MR imaging. RSNA, 2017.

Urachal anomalies are more common than previously thought, with more cases discovered incidentally, because of the increased use of cross-sectional imaging. Although an abnormal persistence of an embryologic communication between the bladder and the umbilicus is often recognized and managed in childhood, it may persist into adulthood, with a greater risk of morbidity. Congenital urachal anomalies that are detected early can benefit from an optimized management including surgical approach with a complete resection of the urachal remnant in cases when spontaneous resolution or medical management has failed. At imaging, the different types of urachal anomalies have a distinct appearance. A patent urachus is recognized as an elongated patent connection between the bladder and the umbilicus. An umbilical-urachal sinus is depicted as a blind focal dilatation at the umbilical end, whereas a vesicourachal diverticulum is a focal outpouching at the vesical end. Urachal cysts are visualized as midline fluid-filled sacs most frequently located near the bladder dome. Complications of urachal anomalies have nonspecific clinical findings and can mimic other abdominal and pelvic processes. Potential complications, such as infection and tumors, should be recognized early to ensure optimal management. Understanding of the embryonic development of the urachus is necessary for the radiologist to diagnose the wide variety of urachal disease. RSNA, 2016.

• No MRI features appear to be specific for rare primary liver malignancies. • Haemorrhage is a helpful sign in diagnosis of primary hepatic sarcomas. • Angiosarcomas may show progressive nodular enhancement towards the centre mimicking haemangioma. • Vessel encasement is a helpful sign in diagnosis of primary hepatic lymphoma.

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