[Gas in a pyelic calculus (author's transl)]

An original case of a gas-containing pyelic calculus is described. This phenomenon in a radiolucent calculus spontaneously visible by computed tomography is attributed to the fissuration of a crystallin calculus. The hypothesis is emitted that, like gallstones, the apparition of gas is a fissuration that may precede the spontaneous disappearance of the calculus.