Urinary bladder masses: techniques, imaging spectrum, and staging.

Bladder carcinoma is the fourth most common cancer in men and women. Knowledge of imaging options and appearance is necessary for both radiologists and urologists. Transitional cell carcinoma is the most common bladder neoplasm with squamous cell and adenocarcinoma found in less than 10% of cases. Benign lesions are uncommon, but some can be suggested by their imaging appearance. Similarly, malignant lesions often have suggestive appearance and/or location. Cystoscopy allows tissue diagnosis and treatment of superficial lesions. Although magnetic resonance imaging (MRI) and computed tomography (CT) both have limitations in detailing depth of muscle invasion, both have a prominent role helping to define the lesion and in staging. This article illustrates the role of MRI and CT in evaluating bladder masses with a discussion of the newer techniques of MR diffusion-weighted imaging and virtual cystoscopy by CT or MRI. This article reviews the multiple benign and malignant lesions of the bladder so that the reader can appreciate the role of cystoscopy, CT, MRI, diffusion-weighted imaging, and virtual cystoscopy in dealing with these relatively common tumors.