Fine needle aspiration cytology of the normal kidney: A cyto-histological and immunocytochemical correlation study.

All cases showed: (a) glomeruli; (b) presence of at least 2 different epithelial cell populations that distribute separately, one representing the proximal tubule and the other more distal segments; and (c) existence of isolated, laminar basement fragments and slender, intact tubular structures. Proximal tubular cells were large with granular cytoplasm, indistinct cell borders, moderate anisonucleosis, and variable presence of pigment. Their immunophenotype was CD10+, AMACR+, PAX8-, and GATA3-. In all cases, cellular aggregates different of nonproximal tubular cells were present. They were smaller than proximal tubular cells with less cytoplasm, better-defined cell borders and uniform nuclei. Their immunophenotype was CD10-, AMACR-, PAX8+, and GATA3+ CONCLUSION: Aspirates from the normal kidney show characteristic features that permit a specific recognition. Different segments of the tubular system can be specifically recognized avoiding confusion with renal tumors. In difficult cases immunocytochemistry is a very helpful aid.