Cystic Appearance on Imaging Methods (Bosniak III-IV) in Histologically Confirmed Papillary Renal Cell Carcinoma is Mainly Characteristic of Papillary Renal Cell Carcinoma Type 1 and Might Predict a Relatively Indolent Behavior of Papillary Renal Cell Carcinoma.

ABSTRACT

AIM: The aim of this study was to determine the proportion of cystic tumors according to preoperative CT (Bosniak III, IV) among surgically treated patients with histologically confirmed papillary renal cell carcinoma (pRCC) and to assess progression rates among patients with and without cystic appearance on imaging. METHODS: A total of 138 patients with pRCC histology surgically treated in the period of January 2007-March 2017 were included. Clinical and radiological characteristics, type of surgery, histopathology results, and follow-up data were recorded and statistically evaluated. RESULTS: Forty-one cases (29.7%) of cystic lesions (10× BIIF, 14× BIII, 17× BIV) were detected by CT. Patients with pRCC1 significantly more frequently presented with cystic appearance on CT (33/78; 42.3%) in comparison to other papillary types (8/60; 13.3%; p = 0.0002). During a median follow-up time of 49.4 months, only 2 patients with cystic lesions progressed after surgery. CONCLUSIONS: Cystic appearance on imaging methods is mainly a characteristic of pRCC1 (42.3%). Cystic morphology on imaging might predict a relatively indolent behavior of all pRCC types. Preoperative scoring systems including tumor growth patterns (cystic vs. solid) are needed for further classification.