Abstract
Multilocular cystic nephroma is a rare benign kidney tumor, which is typically characterized by a unilateral, multicystic renal mass without solid elements. Cystic nephroma has a bimodal distribution and two-thirds of tumors involve children aged between 3 months and 2 years, with male predominance; a second peak affects the age group >30 years old, in which females are predominantly affected. The incidence rate for this rare tumor in patients aged 5-30 years is only 5%. The present study reports a case of a 31-year-old woman affected by a multilocular cystic nephroma in the upper pole of the right kidney, with direct tumor extension into the renal pelvis through a calyx. After a partial nephrectomy on the patient, the pathological examination confirmed a multilocular cystic nephroma in the right renal specimens.