[Spontaneous renal hematoma. Report of 4 cases]

Spontaneous renal and perirenal hematomas are heavy clinical events and, even if rare, they need an early diagnosis in order to plan therapy. A spontaneous renal hematoma should be suspected in case of acute lumbar pain because in more than 60% of cases it is due to a neoplastic lesion. In the other cases it is due to vascular and infectious kidney diseases while in 5 to 15% of cases the cause of the hematoma can not be found. In this paper 4 cases of spontaneous renal hematomas quite interesting both for their rarity and the imaging features are reported. All cases have been treated by medical therapy. According to personal experience and to the literature reports, the primary imaging diagnostic methods are ultrasonography and CT, while renal angiography should be employed when a vascular disease is suspected. In fact, US can provide the diagnosis of spontaneous renal hematoma but only CT can accurately assess its extension and moreover detect the cause of the hemorrhage. In personal experience, MR did not add significative diagnostic information if compared with CT.