A 91-year-old woman was admitted to this hospital by fracture of the right femoral neck. She had undertaken hemodialysis since her age of 89. As Figures show, abdominal CT revealed the enlarged right kidney with multiple cysts, similar to polycystic kidney disease (PCKD). The contralateral left kidney showed atrophy with cysts similar to acquired cystic disease of the kidney (ACDK) that was generally recognized as an end-stage of kidney diseases. Unilateral renal cystic disease (URCD) was first proposed by Levine [1], and similar cases have been also reported in Japan [2]. Although the mechanism of such unilateral morphological changes has never been clarified, the disease features non-familial and non-progressive disorder contrary to PCKD [2]. The present case had no family history of kidney disease and no concurrent problems appeared in PCKD except for mild valvular heart diseases. Unknown additional factors may be involved in her progressive renal damage.

Right kidney is enlarged with multiple cysts typical to polycystic kidney disease (PCKD). Meanwhile, left kidney is rather retracted with cysts as acquired cystic disease of the kidney (ACDK) appeared in final stages of various kinds of kidney diseases.