[Cystic renal adenocarcinoma].

Renal adenocarcinoma presenting as a cystic mass is uncommon and causes difficulty in making the differential diagnosis. Ultrasound and particularly CT are considered to be the most useful diagnostic methods. The usefulness of ultrasound or CT-guided punction-aspiration has yet to be established since the aspirate is often non-specific. The major difficulty encountered when making the differential diagnosis is that of distinguishing cystic renal adenocarcinoma from multilocular cystic nephroma. Multilocular renal carcinoma and multilocular cystic nephroma are the most common adult multilocular renal cystic masses. The latter is more common in the female, whereas cystic renal adenocarcinoma is more common in the male patient.