SP039THE URINE SEDIMENT CYTOLOGY STAINED WITH PAPANICOLAOU IN RARE GLOMERULAR DISEASES: CORRELATION WITH KIDNEY BIOPSY

INTRODUCTION AND AIMS: Urine sediment exam has been introduced since the end of 1800 and is today a tool necessary for the nephrological diagnostics. However, it has limitations in the recognition and distinction of cellular elements. Conversely, the analysis of the urine sediment smear stained by Papanicolau (Urine Cytology) has received less attention apart oncological applications, precancerous lesions, and viral pathologies. However, it allows a better characterization of the cellular elements. METHODS: The aim of the present work was to correlate urine cytology, urine sediment exam and kidney biopsies in cases of rare glomerular diseases. To this aim, urine sediment smears were stained with Papanicolau (Urine Cytology Papanicolau, UCP), the entire slides acquired with the Aperio system and compared to the results of the classical urine sediment and kidney biopsy. RESULTS: Foamy cells (in hereditary FSGS, diabetes etc) are not easily identified in typical urine sediment, whereas are readily recognized with UCP, and in biopsies. These foamy cells are CD68 immunoreactive both in the urine cytology and on tissue sections.Adenine-phosphoribosyl transferase deficit (APRT): UCP shows leucocytes around the typical crystals of 2, 8 Dihydroxyadenine, with and a double contour of the rosette-like crystals, which might be used in differential diagnosis with other rosette-like crystals.Multicentre Castleman disease with secondary amyloidosis: UCP shows several monocytes, eosinophils, and tubular cells with vacuolar degeneration and abundant amorphous protein material. Congo-red deposits, AA-protein and IgM, C3 and fibrinogen deposits in glomeruli can be shown in the biopsy. The interstitium shows monocyte and lymphocyte infiltration, intraglomerular eosinophils.Systemic Lupus erythematosus with kidney involvement: PAS shows monocytes, histiocytes and pathognomonic LE cells (with typical central vacuole). The monocytes are CD68 positive, CD3 and CD20 negative. Bioptic samples can show (rarely) the hematoxylin bodies, which correspond to the LE cells in the urine cytology and infiltration of CD68 cells in the tissue.Nephrotic syndrome from bedbug bite: UCP shows casts with monocytes and eosinophils; the bioptic specimen shows accumulation of eosinophils and monocytes in tubules.Kappa Light chain glomerulonephritis: UCP shows casts covered by monolayers of monocytes/histiocytes. The bioptic specimen shows numerous, k chain immunopositive, intratubular casts.Myeloma cast nephropathy: UCP shows that these are plasma-cells, which can be also observed in the renal bioptic specimen.Chronic thrombotic microangiopathy secondary to drug abuse: UCP shows small clusters of monolayer tubular cells, CD68 immunoreactive, eosinophils, hemosiderin pigment with granular pink appearance; the biopsy shows vascular damage, intratubular eosinophils, and desquamating tubular cells.Glomerulocystic disease: UCP shows abundant protein material, lymphocytes, monocytes and neutrophils without tubular cells and without crystals. The biopsy shows cystic dilatation of Bowman space tubular enlargements throughout. CONCLUSIONS: This is the first cytological characterization of rare nehrological conditions.The cytology smear offers the additional advantage that immunocytochemical techniques can be also applied to characterize cellular elements. Moreover, cytology smears can be stored indefinitely and used in future times for review.