Spontaneous perirenal hemorrhage: what radiologists need to know.

Spontaneous perirenal hemorrhage (SPH), also known as Wünderlich's syndrome, is a rare urological emergency. This article reviews the most common causes of SPH and the role of imaging in establishing the correct diagnosis and in guiding the appropriate therapy. A thorough understanding of underlying etiologies, imaging appearances, optimal imaging techniques, and follow-up protocols are crucial to recognize patients with SPH due to benign disease and avoid unnecessary nephrectomies.