Balantidium coli

Ciliary tuft of columnar epithelial cell in cervical smear (Papanicolaou stain, oil immersion). Detached ciliary tufts of columnar epithelial cells may be found in cervicovaginal smears, peritoneal fluid, fluid from ovarian cysts, culdocentesis fluid, and other body secretions. In wet mount preparations, they may retain motility for several hours. These cell fragments usually measure 5 to 10 µm in length and lack nuclei. The presence of cilia may erroneously suggest ciliated parasites. The finding of these ciliated tufts in respiratory secretions and in other specimens submitted for cytologic examination has misled laboratory microscopists into believing that parasitic organisms were present.