--- a
+++ b/data/text/S0004-06142006000300015-1.txt
@@ -0,0 +1,4 @@
+A 50-year-old patient with a history of recurrent renal lithiasis consulted for recurrent haematuria and a feeling of discomfort. Serial cytological examination of urine showed the presence of atypical cells suspicious for malignancy. Imaging studies revealed a heterogeneous lesion occupying almost the entire right renal pelvis. Total nephrectomy and partial ureterectomy were performed, revealing a kidney measuring a maximum of 10.5 x 5 cm with an irregular, heterogeneous brownish lesion in the renal pelvis with haemorrhagic areas and other slightly yellowish, shiny areas with an extremely soft consistency when cut. This lesion, relatively well delimited, did not invade the renal parenchyma or the renal sinus and was limited to the pyelocaliceal system, although it compressed the cortex with expansive margins at one of the renal poles. Histological examination showed that the lesion consisted of well-demarcated tumour nests with no evidence of invasion of the renal parenchyma, encompassing a central mucinous matrix which constituted more than 50% of the tumour volume. Loose neoplastic cells and nests of smaller size than those located at the peripheral level were found floating within this matrix. The tumour cells showed polygonal morphology with central nuclei without apparent nucleoli and little atypia as well as eosinophilic and clear cytoplasm. In the areas bordering the mucinous matrix, a shy glandular differentiation was observed, coinciding with the observation of some nucleoli and a slight increase in nuclear atypia. The tumour cells showed intense immunopositivity for EMA, CK 7 and mild immunopositivity for CK20; this, together with the morphology, confirmed the urothelial nature of the neoplasm.
+With all the above data, the diagnosis of low-grade transitional cell carcinoma with intense mucinous differentiation of the renal pelvis (colloid carcinoma) was made.
+
+