Growth rates are similar in potentially benign and malignant small renal masses detected incidentally.
OBJECTIVE
Generally small renal masses grow at slow rate; some of them do not exhibit any growth. Does it mean that they are less aggressive? The aim of our study was to compare the growth of enhancing, non-enhancing solid renal masses, angiomyolipomas and complex renal cystic masses < or =4 cm in diameter.


METHODS
12 patients with solid enhancing, 20 with solid non-enhancing, 8 with angiomyolipomas and 25 with Bosniak II/IIF/III and IV masses were enrolled and prospectively studied during the surveillance period. The mean diameter of the lesion at presentation was 3.5; 3.1; 3.2 and 3.9 cm, the mean period of observation was 47; 48; 35 and 48 for each group respectively. All masses were detected incidentally. Progression rates (the largest diameter was calculated) were compared among the groups.


RESULTS
The range and mean growth rates among all groups after one year of observation were (0.0-0.3; 0.2 cm); (0.0-0.3; 0.2 cm); (0.0-0.4; 0.3 cm); (0.0-0.3; 0.1 cm); (0.0-0.2; 0.1 cm); (0.0-0.0; 0.0 cm) and (-0.6-0.0; -0.2 cm) for 7 groups respectively. Overall 55.4% of masses did not exhibit any growth. We did not monitor any pathological lymph node enlargement, distant metastases in any group of patients. Overall, 85% of masses that exhibited growth during the first year did so at the end of follow up.


CONCLUSIONS
The vast majority of small solid and complex cystic renal masses exhibit similar slow growth rates. According to these results, urologists can not predict the biological potential of the mass based on radiographic criteria and growth rates only (Tab. 2, Ref. 12).
Kollarik
B
B
Department of Urology, University Hospital-Petrzalka, Bratislava, Slovakia. bkollarik@gmail.com
Romancik
M
M
Obsitnik
M
M
D000368:Aged; D018207:Angiomyolipoma / Q000000981:diagnostic imaging / Q000473:pathology; D018450:Disease Progression; D006801:Humans; D033162:Incidental Findings; D052177:Kidney Diseases, Cystic / Q000000981:diagnostic imaging / Q000473:pathology*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D011859:Radiography