Multiple calculi within noncommunicating pyelogenic renal cyst.

Multiple calculi were found within a cystic renal mass, which had no apparent communication with the renal collecting system. Radiography, sonography, and surgical examination suggested a serous cyst of the kidney. Histopathology proved the cyst to be pyelogenic origin. The origin and differences of serous and pyelogenic cysts of the kidney are discussed.