Sudden pain in the right flank
Discussion:
The hyperechogenicty with ultrasound and the low fat density on the CT scan are characteristic for an angiomyolipoma.
Large angiomyolipomas especialy the large exophytic angiomyolipomas can cause a perirenal and retroperitoneal hemorhage. A spontaneous perirenal hemorrhage is called the Wunderlich's syndrome. The most common cause of the Wunderlich syndrome is an angiomyolipoma. That was also the case in this patient. In cases of large hemorrhagic exophytic angiomyolipomas embolisation or surgery are treatment options. This patient remained stable and untill now has been conservatively treated.
References
Albi G, del Campo L, Tagarro D.Wunderlich's syndrome: causes, diagnosis and radiological management.
Clin Radiol. 2002 Sep;57(9):840-5.