Is imagery distinctive in papillary renal cell carcinoma subtypes?

The subdivision into two entities of papillary renal cell carcinoma (PRCC) was established on histological criteria. It's in fact possible to distinguish the two subtypes by the means of radiological and progressive data. The subtype 1 is associated with the favorable profile. The ultrasound and especially CT urography ensure an accurate diagnostic approach with substantial therapeutic and prognostic involvement. The aim of the study is to define the radiological features that distinguish the two subtypes of renal papillary carcinoma, and to study the radiological predictive factors of locoregional recurrence, metastases free survival and specific survival.

It's about a monocentric, retrospective study led between January 2005 and June 2017, gathering 49 cases of operated PRCC. The study concerned patients over the age of 18, who were diagnosed after anatomopathological examination of the operative specimen (enlarged nephrectomy or conservative surgery). Cases in which diagnosis was made by renal biopsy were excluded. The comparative study concerned ultrasound and CT scan data. Univariate and multivariate analysis were performed to determine factors having a prognostic value in terms of locoregional recurrence, metastases-free and specific survival.

On the ultrasound, the subtype 1 tumors were significantly homogenous with regular contours. Tumors were globally spontaneously hypodense and hypo vascular in 97,8% of cases. Enhancement was significantly more heterogonous for subtype 2 (p=0,01). Intratumoral necrosis and adenomegalies were associated with subtype 2 (p=0,0001 and 0,005). The predictive factors of locoregional recurrence, metastases-free survival and specific survival in univariate analysis were the contours' aspect, moderate enhancement and the presence of adenomegalies. On multivariate analysis, only the irregular contours were retained for locoregional recurrence-free survival and specific survival.

Significant differences between the PRCC subtypes were observed when studying the radiological data. Irregular contours, adenomegalies and enhancement degree seemed to predict the progression of PRCC after curative surgery.