Stojanović, Milan (24831366700)Milan (24831366700)StojanovićGoldner, Branislav (24830026000)Branislav (24830026000)Goldner2025-06-122025-06-122008https://doi.org/10.2298/SARH0804166Shttps://www.scopus.com/inward/record.uri?eid=2-s2.0-52049105878&doi=10.2298%2fSARH0804166S&partnerID=40&md5=286dea65f9f3b6c28de26a133bf8ec1chttps://remedy.med.bg.ac.rs/handle/123456789/10717Introduction Malignant cystic renal tumour is a rare variant of renal malignancy. Cystic neoplasm results from haemorrhage, necrosis and colliquation of a solid tumour or tumour occurring within the wall of a cyst. That pathoanatomic substratum reflects characteristic sonographic features indicating its malignant nature. It is important to distinguish a simple cyst (not requiring surgery) from intracystic malignant lesion because it requires surgery. Case outline The authors present a 59-year-old woman with a sonographic finding of a simple cyst in the upper pole of the right kidney revealed during gynaecological ultrasonography. Immediately afterwards, the radiologist performed renal sonography and its finding was a cystic lesion suggestive of malignancy. Further evaluation by CT scan showed that the lesion was clearly malignant. After surgery, the histological finding verified cystic renal cancer. Conclusion Ultrasonography may reveal a complex cyst and solid mass but requires an experienced sonographer. Contrast CT scan would be performed to examine the "suspicious" lesion because it clearly shows if a cystic lesion is benign or malignant.CystMalignant cystic renal tumourUltrasound