Identification of tubular cell nephron segment origin in renal fine-needle aspirates

Currently there are no definitive criteria for identification of the nephron segment origin of tubular cells in renal fine-needle aspirates. This information would be useful for determining the cortical or medullary location of aspirate specimens. To establish morphologic criteria for identifying tubular cell origin, we evaluated 60 allograft and four native kidney aspirates with immunocytochemistry (IC) and May-Grünwald-Giemsa (MGG) stains. IC markers included URO-3 and Tetragonolobus purpuras for proximal cells, URO-5 and Arachis hypogaea for distal cells, and URO-5, Arachis hypogaea, and anti-cytokeratin antibody for collecting duct cells. Cell and nuclear areas were measured morphometrically, and cell grouping and MGG staining characteristics were assessed. Proximal tubular cells have an area of 335 +/- 112 microns2 (IC strains) and 350 +/- 107 microns2 (MGG stain) with a nuclear:cytoplasm (N:C) ratio of 1:4. The cells occur singly or in small clusters of four to seven cells with abundant pale cytoplasm. Distal tubular cells measure 224 +/- 66 microns2 (IC stains) and 171 +/- 38 microns2 (MGG stain) with an N:C ratio of 1:2. They often form honeycomb aggregates of 10 to 20 cells with moderately dense cytoplasm. Cells of collecting ducts have areas of 96 +/- 32 microns2 (IC stains) and 99 +/- 35 microns2 (MGG stain) with an N:C ratio of 2:3. These cells are found in glandular clusters of two to seven cells with dense cytoplasm. All tubular cell size and staining characteristics were the same in allograft and native kidney samples.(ABSTRACT TRUNCATED AT 250 WORDS)