[A Rare Case of an Epidermoid Cyst Originating from the Upper Urinary Tract].

Epidermoid cysts originating from the upper urinary tract are extremely rare, and only five cases have been reported previously. We report a rare case of epidermoid cyst that originated from the right ureter : A 76-year-old man presented with asymptomatic gross hematuria. Computed tomography showed a right ureteral tumor (14×8 mm in size). Retrograde pyelography showed a defect (14 mm diameter) of the contrast medium in the same region. Urinary cytological examination indicated class III. A ureteral tumor was clinically indicated, and retroperitoneoscopic-assisted radical nephroureterectomy was performed. Postoperative histopathological examination of the resected specimen showed ureteral epidermoid cysts without any malignancy.