Epidermal Cyst in the Renal Pelvis: A Case Report with Review of the Literature

ABSTRACT

We report here on a case of an epidermal cyst arising in the kidney. This cyst occurred in a 61-year-old woman with a past history of several attacks of ureteral stones and she received treatments of extracoporeal shock wave lithotripsy and open nephrolithostomy. On the intravenous pyelogram, a relatively well demarcated, 5x5 cm-sized lesion with calcification was detected in the renal pelvis and calices. The lesion was removed by percutaneous nephrolithotomy. Histologically, the lesion had the same morphologic feature as a typical epidermal cyst arising in the skin. It has been postulated that the intrarenal epidermal cyst arises either from epidermal remnants or it results from traumatic implantation of transformed epithelium. Considering the past history of the patient, it might well be suspected that the present case occurred as a result of traumatic implantation of metaplastic squamous epithelial cells. We report here on a very interesting case of an epidermal cyst in the renal pelvis with a review of the relevant literatures.