Atypical renal cysts

Atypical renal cysts are suspicious for malignancy. It is hard in some cases to give a sharp radiological diagnosis and propose an appropriate management.To give the histological results of the operated atypical renal cysts and to establish a correlation between the radiological findings and histological features.Between January 2001 and December 2012, 22 patients have been operated in our department for atypical renal cysts. There were 10 type III and 12 type IV Bosniak lesions. We have reported clinical, epidemiological and radiological findings. We have analyzed the histological results taking into consideration the radiological findings.According to histological findings, 7 among the 10 type III lesions were benign (70%). However, only one case of benign tumor was noted in type IV lesions (8.3%). There was no evident correlation between tumors size and histology. With a median follow up of 48 months, three patients died because of locally advanced tumors.Management of atypical renal cysts remains difficult. A careful computed tomography staging is essential before treatment. Type III and type IV Bosniak cysts were malign in 30% and 91% of cases, respectively. There was no correlation between tumor size and malignancy. A nephron sparing surgery should be proposed whenever possible.