Upper urothelial carcinoma in Balkan endemic nephropathy and non-endemic regions: a comparative study of pathological features.

ABSTRACT

Upper urothelial carcinoma (UUC), a rare neoplasm, occurs more frequently in some regions of Balkan countries than in other areas in the world. The aim of this study is to compare phenotypic morphological characteristics of UUC in Balkan endemic nephropathy (BEN) region and control rural and city populations free of BEN, and to determine the characteristic(s) that could discriminate tumors in endemic and non-endemic regions. The authors analyzed biopsies from 88 patients with UUC, 40 patients who live in Balkan endemic (BEN) settlements and 48 control subjects. The histological sections were used to assess morphological variables histologic grade, pathologic stage (pT), growth pattern, pattern of invasion, lympho-vascular invasion (LVI), presence of necrosis and metaplastic changes (squamous or glandular) within the tumor. Statistically significant differences between the groups were found concerning tumor grade, pattern of invasion, growth pattern and metaplastic changes. High-grade tumors and trabecular/infiltrative patterns of invasion were more frequent in the group of BEN tumors (chi(2)=4.583, p<0.05; chi(2)=8.064, p<0.05). Moreover, solid growth and metaplastic changes are significant in BEN tumor, chi(2)=9.696, p<0.01; chi(2)=9.35, p<0.01, respectively. Discriminant analysis of morphological variables had indicated that BEN and control tumors are significantly different (Wilks' lambda=0.833, chi(2)=15.044 and p<0.05). The best characteristic that differentiated them was growth pattern; i.e., solid growth for BEN tumors and papillary for control tumors.