Mixed tumor of the kidney

Mixed epithelial and stromal tumour (MEST) of the kidney, is a recently recognized and rare entity .We herein reported the case of a 56 years old post-menopausal woman who presented with right abdominal pain. Her physical examination was unremarkable. Ultrasonography revealed the presence of a right cystic renal mass in the interpolar region extending into the pelvis. The tumor was considered Bosniak 4 category and a right nephro-ureterectomy was performed. The histological examination of the tumor revealed a mixed tumor with both epithelial and stromal pattern.