RESUMO
A well-marginated fat-containing renal lesion gives strong suspicion of renal angiomyolipoma (RAML) that usually requires no surgical intervention. Radiologically, renal masses with a large amount of fat can rule out renal cell carcinoma (RCC). Calcifications are very infrequent in RAML. However, the presence of calcifications in a fat-containing renal lesion is highly suggestive of RCC. These lesions should undergo surgical resection and histopathological assessment to reach the right diagnosis and avoid poor outcomes if diagnosed late. We present a case of bilateral renal tumors, in which one of them radiologically contained abundant fat with calcifications on CT scan, which was confirmed to be an RCC on histopathological examination.
RESUMO
Cytokeratins belong to the family of intermediate filaments. They are expressed in a highly specific manner in epithelial cells where they play a crucial role in the integrity and mechanical stability of the cells. Several types of cytokeratins have been described in normal as well as neoplastic urothelium. In the case of urothelial neoplasms expression of CK20 and CK5/6 has been shown in several studies to have diagnostic and prognostic implications. Thus, low-grade urothelial carcinoma manifests CK expression limited to the umbrella cells, while high-grade tumors usually have an expression in the entire thickness of the urothelium except for the basal layer. CK5/6 expression on the other hand is expressed in the basal cells in all low-grade and some high-grade urothelial carcinomas. Diffuse CK20 staining accompanied by loss of CK5/6-positive basal layer is usually associated with aggressive clinical behavior. Double staining of the slides for these cytokeratins may facilitate proper interpretation and correlation.
