[Kidney tumor in 12-year-old girl--case study of the rare histopatologic form of neoplasm in children].

The authors present an atypical case of MEST uncovered in 12-year-old girl diagnosed with recurrent pyuria and persistent albuminuria with concomitant hypertension. Urine changes persisted despite the antibiotics therapy and they were accompanied with aseptic urine cultures. While investigating these changes, USG, urography, CT and MRI were performed and these manifested tumor-like change in the right kidney. Right-side nefrectomy was performed. Microscopically MEST was found while infection was found in parenchyma. Mixed epithelial and stromal tumor is a very rare kidney tumor that occurs almost exclusively in perimenopausal women or women after a long-term estrogen replacement. There are only few cases of this tumor in premenarcheal girls described in literature.