Very large renal calculi are unusual because the growth of stones is dependent on continued secretion of urine. Since most stones cause arrest of renal function before they reach giant proportions, stones weighing more than 100 gm. are not often encountered.
The largest stone described in the recent literature is that reported by Duncan1 to be a "mammoth" kidney stone weighing 315 gm. The largest stone from Joly's2 series weighed 567 gm. The next largest stone weighed 147 gm. Legueu3 lists seven "colossal" renal stones that weighed over 500 gm., but most of these were found at autopsy. Except for Joly's and Legueu's reports, there is no record of a solitary renal calculus larger than the one to be described. This case is reported not only because of the massive stone obtained at surgery but also because of the extreme degree of renal damage that still was