Spontaneous disappearance of a renal arteriovenous malformation.

We describe herein a case of complete spontaneous disappearance of a congenital arteriovenous malformation (AVM). A 28-year-old male was hospitalized for right flank pain and gross hematuria, followed by bladder tamponade. To improve the patient's symptoms, bladder irrigation was performed. Cystoscopy demonstrated bloody urine from the right ureteral orifice. Right selective renal arteriography demonstrated tortuous, coiled vascular channels with early filling of the renal vein. Thus, right renal AVM was diagnosed. However, the patient refused further treatment and was discharged. One year later, massive hematuria recurred with bladder tamponade and the patient was rehospitalized. Renal arteriography did not show any evidence of AVM and there has been no hematuria since.