Intrarenal Epidermal Cyst

Ha, Seong Yup; Kwon, Joon Bum; Lee, Kwang Suk; Yoo, Eun Sang; Park, Yoon Kyu

Abstract

Epidermal cysts are benign cysts, which rarely localize in solid organs, but have an unclear pathogenesis. Herein, a case of an intrarenal epidermal cyst, in a 60-year-old woman with right flank pain, is reported. Multiple renal stones in the right kidney were identified by an intravenous pyelogram. A percutaneous nephrolithotomy (PCNL) was performed under the assumption of renal stones. Amorphorous cysts, containing calcification, were identified during the PCNL, which were histologically identical in appearance to an epidermal cyst within the skin. We suspected the pathogenetic mechanism of this lesion was a metaplasia of traumatic origin, due to the patient's history of renal stones, which had been previously treated with an open nephrolithotomy. According to the literature, an intrarenal epidermal cyst was usually treated by nephrectomy, under the assumption of a renal mass. Although the intrarenal epidermal cyst was incidentally found during the PCNL, an additional nephrectomy was not performed as it had almost been removed.