[Retroperitoneoscopy to extract an amorphous matrix calculus of the right kidney].

The female patient underwent multiple extracorporal shockwave treatments and an ureterorenoscopy during which an amorphous renal mass was found. A retroperitoneoscopy was performed with extraction of a large amorphous matrix calculus. Today, the prevalence of matrix calculi is very low. They are associated with and caused by urinal-infections. Delayed diagnosis in radiological-imaging procedures is typical for these stones. The minimal-invasive approach via retroperitoneoscopy seems to be an intriguing alternative to the established procedures like percutaneous nephrolitholapaxy.