Presentation of one case of Wünderlich's syndrome secondary to spontaneous mesorenal fracture due to renal angiomyolipoma. In our case, the therapeutical approach is based in the need to preserve the functional renal unit. Wünderlich's syndrome or spontaneous perirenal haematoma can occur for a variety of causes, the most frequent ones being renal adenocarcinoma and renal angiomyolipoma. The latter is a hamartoma made up of three different tissue lines: smooth muscle cells, blood vessels and adipose tissue. Based on our case, we discuss the clinical, prognostic and therapeutical aspects related to renal angiomyolipomes.