[Rupture of renal cyst secondary to blunt trauma: case report and review of the literature].

Rupture of a renal cyst can be spontaneous, iatrogenic or consequent to a trauma even of minor entity, especially in predisposing conditions such as cysts, tumors or hydronephrosis. Kidneys are, in fact, involved in about 25% of abdominal traumas. The grading system of the American Association for the Surgery of Trauma (AAST) classifies renal injuries into five categories based on renal involvement and abnormalities detected on contrast-enhanced CT, modality of choice in the evaluation of abdominal trauma with suspicion of intraperitoneal hemorrhage. Hematuria and/or flank pain are the most frequent presenting symptoms, although some patients may be also asymptomatic. Treatment is usually conservative, but sometimes nephrectomy may be necessary. In our manuscript we describe the case of a patient who comes to our observation with left side pain reporting a minor accidental fall occurred the day before. Ultrasound examination and CT with contrast medium revealed hemoretroperitoneum resulting from rupture of a hemorrhagic renal cyst. We will describe the imaging characteristics and therapeutic choices below.