[Diagnostic and therapeutic problems posed by renal or para-renal masses of cystic appearances].

The authors report some forty cases of renal masses, cystic in appearance and having raised a certain number of diagnostic or therapeutic problems. These masses included 7 cystic carcinomas, 3 benign tumors of cystic appearance and 28 cysts including 2 infected and 2 hydatid cysts. No paraclinical investigation is infallible in confirming the nature of the mass in doubtful cases, and pre-operative diagnosis is more easily obtained by investigation including the majority of standard imaging methods often completed by puncture. Amongst clinical factors which raise doubts as to the benign nature of the cystic mass seen, hematuria remains the most important, other symptoms and signs being of little significance. With regard to imaging, septate calcified masses with echoes within them, with a thick wall or high CT scan density are theoretically suspect. The same applies to masses having rapidly increased at two successive investigations or where puncture fluid is bloody. In all cases if proof of the benign nature cannot be obtained, surgical exploration would appear to be required.