[Calculi of papillary origin. An undisputed reality].

In 1936, Randall formulated a hypothesis concerning stone formation related to the renal papillae. Randall's hypothesis, discussed for many years, was confirmed by Cifuentes in 1983. The authors studied 830 cases of papillary stones, eliminated spontaneously, 16 of which had a typical Randall plaque with mineralized collecting tubules (1.9%). This study was conducted by scanning electronic microscopy (SEM) using an EDX system. The papillary origin of several renal stones can be confirmed in this way. The origin of these stones would remain unknown without the use of these modern techniques.