Clinical predictors of renal mass pathological features

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Widespread use of abdominal imaging has changed the landscape of kidney lesions with an increase in serendipitously detected small renal masses (SRMs) that represent a new epidemiological entity that requires further understanding and potentially reconsideration of current treatment schemes. We identified specific preoperative factors associated with renal mass pathological features, and specifically with an increased risk of malignant, potentially aggressive disease. These factors should be considered when evaluating potential candidates for active surveillance and ablative techniques. OBJECTIVE To evaluate the influence of radiographic tumour size and other preoperative variables on the pathological characteristics of the lesion to determine the distribution of pathological features and assess preoperative risk factors for potentially aggressive versus probably indolent renal lesions. PATIENTS AND METHODS Retrospective review of records for 768 patients who underwent surgery for single, sporadic renal mass between 2000 and 2008 in a tertiary academic institution. Demographic, radiographic and pathological variables were recorded and analysed with regression analyses for risk factors for potentially aggressive pathological features (malignant pathology, high Fuhrman grade, lymphovascular invasion and extracapsular extension). RESULTS Malignancy was pathologically confirmed in 628 (81.8%) specimens. Radiographic size was significantly associated with malignancy (versus benign pathology; OR = 1.13, P= 0.001), high Fuhrman grade (OR = 1.21, P < 0.0001), vascular invasion (OR = 1.19, P < 0.0001) and extracapsular extension (OR = 1.23, P < 0.0001). Age, symptomatic presentation, solid appearance and radiographic size were independent predictors of potentially aggressive disease, whereas for male gender (OR = 1.43, P= 0.062) a trend toward statistical significance was noted. CONCLUSIONS Age, male gender, radiographic size and appearance, as well as symptomatic presentation, are associated with an increased risk of malignant, potentially aggressive disease. These factors should be considered when evaluating management options for a solitary enhancing renal mass.