 Causes of hematuria can arise from anywhere along the urinary tract and are generally divided into nephrogenic and urogenic causes. Renal parenchymal disease is the most common benign nephrogenic cause of hematuria [1]. Common benign urogenic causes of hematuria include urolithiasis, infection, and benign prostatic hypertrophy [1]. Malignant causes can occur anywhere in the urinary tract and are the main entity that must be excluded during the imaging evaluation of hematuria. The most common factors associated with development of a urinary malignancy include gross hematuria, male gender, age >35 years, smoking, occupational exposure to chemicals, analgesic abuse, history of urologic disease, irritative voiding symptoms, history of pelvic irradiation, chronic urinary tract infection, exposure to known carcinogenic agents or chemotherapy, and chronic indwelling foreign body [1,2]. Gross hematuria has a high association with malignancy of up to 30% to 40%, and therefore all patients with gross hematuria should have a full urologic workup [1]. Conversely, patients with microhematuria have a low risk of malignancy ranging from 2.6% to 4%, and, in most patients with asymptomatic microhematuria, a cause is never found [1,2]. Patients without risk factors and with an identified benign cause of microhematuria including vigorous exercise, infection, trauma, menstruation, or recent urologic procedure are unlikely to gain any benefit from a complete imaging workup of microhematuria [1,2,5,6]. Patients with suspected urinary tract infection as a cause of microhematuria should have urine cultures performed, preferably before antibiotic therapy, to confirm an infection [1,2]. Patients with a suspected cause of microhematuria, including interstitial cystitis or benign prostatic hyperplasia, should have the appropriate clinical workup before undertaking imaging, including a pelvic examination in women, a rectal examination in men, and cystoscopy [1,2,6]. Interstitial cystitis, in particular, should
Hematuria.  Causes of hematuria can arise from anywhere along the urinary tract and are generally divided into nephrogenic and urogenic causes. Renal parenchymal disease is the most common benign nephrogenic cause of hematuria [1]. Common benign urogenic causes of hematuria include urolithiasis, infection, and benign prostatic hypertrophy [1]. Malignant causes can occur anywhere in the urinary tract and are the main entity that must be excluded during the imaging evaluation of hematuria. The most common factors associated with development of a urinary malignancy include gross hematuria, male gender, age >35 years, smoking, occupational exposure to chemicals, analgesic abuse, history of urologic disease, irritative voiding symptoms, history of pelvic irradiation, chronic urinary tract infection, exposure to known carcinogenic agents or chemotherapy, and chronic indwelling foreign body [1,2]. Gross hematuria has a high association with malignancy of up to 30% to 40%, and therefore all patients with gross hematuria should have a full urologic workup [1]. Conversely, patients with microhematuria have a low risk of malignancy ranging from 2.6% to 4%, and, in most patients with asymptomatic microhematuria, a cause is never found [1,2]. Patients without risk factors and with an identified benign cause of microhematuria including vigorous exercise, infection, trauma, menstruation, or recent urologic procedure are unlikely to gain any benefit from a complete imaging workup of microhematuria [1,2,5,6]. Patients with suspected urinary tract infection as a cause of microhematuria should have urine cultures performed, preferably before antibiotic therapy, to confirm an infection [1,2]. Patients with a suspected cause of microhematuria, including interstitial cystitis or benign prostatic hyperplasia, should have the appropriate clinical workup before undertaking imaging, including a pelvic examination in women, a rectal examination in men, and cystoscopy [1,2,6]. Interstitial cystitis, in particular, should