Needle puncture of cystic renal masses: a survey of the Society of Uroradiology

A survey of 114 members of the Society of Uroradiology provided data on the results of needle punctures of cystic renal masses in approximately 16,000 cases. The 73 respondents reported that cyst puncture is currently performed only for specific indications, that opacification is only occasionally performed after puncture, and that cytology is the laboratory procedure of choice for aspirated fluid. While all respondents accepted sonographic confirmation of cysts seen on nephrotomography, only 92% accepted sonography alone as diagnostic, compared to 100% for CT alone. Aspiration of clear fluid (usually an indicator of benignity) with positive or negative cytology, occurred in 19 cystic renal malignancies. Thus, gross and laboratory characteristics of aspirated fluid are not conclusive in diagnosing cystic lesions. CT should be the final arbiter in suspicious lesions.