PURPOSE: To identify size criteria for complex cystic renal masses that can distinguish renal cell carcinoma from benign cysts supplementing the Bosniak classification. MATERIALS AND METHODS: We reviewed the records of 97 patients who underwent surgery for complex cystic renal masses from January 2001 to April 2010. The pathological results were compared with the lesion sizes measured by preoperative computed tomography and other radiological features (contrast enhancement, irregularities of cyst walls and septa, and calcification) were also obtained for categorization according to the Bosniak renal cyst classification. RESULTS: Malignancy was significantly associated with cyst size (>2 cm), male gender, and younger patient age (<50 years). According to the Bosniak classification, there was no category I cyst, and all 8 category II cysts were benign. However, 3 of 18 (17%) category IIF cysts, 21 of 39 (54%) category III cysts, and 29 of 32 (90%) category IV cysts were malignant. All category IIF cysts were benign in patients older than 50 years of age. CONCLUSION: Many complex cystic renal masses smaller than 2 cm were benign. We suggest that lesion size should be taken into account when formulating treatment plans for complex cystic renal masses.
Adolescent ; Adult ; Age Factors ; Aged ; Carcinoma, Renal Cell/diagnosis/radiography ; Child ; Child, Preschool ; *Diagnosis, Differential ; Female ; Humans ; Infant ; Kidney Diseases, Cystic/*diagnosis/radiography ; Kidney Neoplasms/*diagnosis/radiography ; Male ; Middle Aged ; Sex Factors ; Tomography, X-Ray Computed ; Young Adult

Although recently, there have been introduced many new diagnostic tools such as renal scanning and renogram, intravenous urogram remains to be one of the most useful method of urological diagnosis. Therefore it seems warranted to review 363 cases of intravenous urograms performed in the department of urology, St. Mary's hospital, Catholic Medical College during the period of January, 1962 to June, 1964. Among others, especial attention was paid to 60 cases of nonvisualizing kidneys. Of 60 nonvisualizing kidneys, renal tuberculosis occupied 27 cases(45%); ureteral and renal stones 13(21.6%); hydronephrosis 9(15%) (metastatic carcinoma 6(10%)and surgical manipulation 3(5%); Wilms' tumor 5 (8.3%) chronic atrophic pyelonephritis 3(5%) ; One case each of renal cell carcinoma, cystic kidney and thrombosis of the renal artery. Inasmuch as the present study revealed renal tuberculosis to be the most common cause of nonvisualizing kidneys, it is felt that one should always consider the possibility of tuberculosis in the diagnosis of nonvisualizing kidneys in Korea. This fact should be stressed because nontuberculous pathology such as chronic pyelonephritis has been implicated to be the most frequent cause of nonvisualizing kidneys by American authors.
Carcinoma, Renal Cell ; Diagnosis ; Hydronephrosis ; Kidney Diseases, Cystic ; Kidney* ; Korea ; Pathology ; Pyelonephritis ; Radiography* ; Renal Artery ; Thrombosis ; Tuberculosis ; Tuberculosis, Renal ; Ureter ; Urology ; Wilms Tumor