Diagnosis and treatment of cystic nephroma and the mixed epithelial and stromal tumor: 13 cases report

Abstract

Objective To discuss the characteristics and treatment of the cystic nephroma (CN) and the mixed epithelial and stromal tumor (MESTK).Methods A retrospective collection of the clinical data of 7 CN patients and 6 MESTK patients from Jan.2000 to Apr.2012.In CN cases,there were 3 males and 4 females.Mean age was 50 years (36 to 69 years).Five cases had no symptom and were found by ultrasonic examination.Two patients had lower back discomfort.There were 3 on left side,4 right.The maximum diameter was 1.0 to 8.5 cm.Seven cases were graded as Bosniak Ⅱ by CT scan.Preoperatively 4 were diagnosed as multilocular renal cysts,2 cystic renal cell carcinoma.One case diagnosed as muhilocular renal cyst initially was diagnosed as CN when recurrence.On 6 MESTK patients,there were 1 male and 5 females.Mean age was 38 years (16 to 50 years).Four cases had no symptom and were discovered by ultrasonic examination.Two patients had lower back discomfort.There were 2 cases on left side,4 right.The maximum diameter was 3.4 to 11.0 cm.Five cases were graded as Bosniak Ⅲ and 1 was graded as Bosniak Ⅳ by CT scan.Six patients were all diagnosed as cystic renal cell carcinoma preoperatively.Results In the 7 cases of CN patients,3 accepted retroperitoneal laparoscopic cyst unroofing,2 accepted retroperitoneal laparoscopic partial nephrectomy,1 patient with a preoperative diagnosis of cystic renal cell carcinoma got retroperitoneal laparoscopic radical nephrectomy.One patient recurred 7 years after retroperitoneal laparoscopic cyst unroofing,and underwent open partial nephrectomy.All the 6 MESTK patients underwent retroperitoneal laparoscopic radical nephrectomy.Nine cases were followed up for 15 months to 9 years without recurrence.Conclusions CN and MESTK are rare benign tumors of the kidney.Few MESTK have malignant tendency.Preoperative misdiagnosis is frequent.Multi-cystic lesions with no mural nodules should take CN/MESTK into consideration.Especially when the lesions located convex to the pelvis,it should be highly suspected of CN,and the possibility of partial nephrectomy should be assessed.Cyst unroofing for CN may have risk of recurrence. Key words: Mixed epithelial and stromal tumor of kidney; Cystic nephroma; Diagnosis; Therapy