ThinPrep® (TP) Morphology of Amebic Cysts in Anal Cytology Samples: Morphologic Features and Comparison to Conventional Smears
PA Rodriguez Urrego, D Caplivski, V LaBombardi, H Chen, AH Szporn. Mount Sinai School of Medicine, NY, NY
Background: Although the cytomorphology of amoebae is known from conventional smears (CV), their features in TP have not been previously described. In this case series, we describe the morphological features of various amebic cysts in anal TP (ATP).
Design: Files from 01-2006 through 09-2009 were reviewed to identify all anal/rectal TP which were positive for amoebae. Cytomorphological characteristics, including background, preservation, size (S), cytoplasm (C), number of nuclei (N), chromatoid bodies (CB) and capsule were evaluated and compared.
Results: A total 1527 ATP specimens, all referred from the infectious disease clinic as high risk patients for anal squamous intraepithelial lesions, were found. 0.7% (n=11 cases) were positive for parasites (14 organisms). 13 amoebic cysts were identified, including Entamoeba histolytica (EH), Entamoeba coli (EC), Iodamoeba bütschlii (IB), Endolimax nana (EN), 1 case had a protozoan cyst Blastocystis hominis (BH). IB was the most common identified parasite (50%). 3 cases had 2 organims: EC and IB (2) and EH and BH (1). All cases revealed: clean background, no obscuring artifacts, good cellular detail, double contour membrane, crisp and easily visualized internal structures. All parasites were separated from surrounding cellular material,and were easily visible; except for one case that showed degenerative changes. All parasites were in the cyst stage. Morphologic comparisons of the cysts with those described in CV are displayed in the table.
|EH (3)||S||5-20||9 (8-10)|
|CYT||diffuse glycogen, mahogany brown||soft, light blue|
|CB||large bars or thick rods||thick rod, dark blue|
|EC (3)||S||17 (10-33)||17 (13-19)|
|CYT||large mass, ill defined dark brown||dense, dusky blue|
|CB||sometimes, splinter like||-|
|IB (6)||S||10 (5-18)||10 (8-10)|
|CYT||large mass, compact, dark brown, vacuole||finely granular, dark blue,translucent vacuole|
|N||1-2||1 (dark, piknotic)|
|EN (1)||S||9 (5-14)||7|
|CYT||absent, ill-defined brown||granular, blue|
|CB||small, spherical or elongated granules||red, small, round granules|