Atrophic vaginitis versus invasive squamous cell carcinoma on ThinPrep cytology: can the background be reliably distinguished?

The presence of pronounced squamous epithelial atrophy/atrophic vaginitis on cervicovaginal preparations can present diagnostic difficulties, particularly in the presence of a granular background. The purpose of this study was to compare and contrast the background material present on ThinPrep cytology in cases of atrophic vaginitis and invasive squamous cell carcinoma (SCC). Thirty-three cases of atrophic vaginitis showed a heavy background of granular material containing acute inflammatory cells, apoptotic bodies, and fresh/crenated red blood cells. These findings were indistinguishable from those present in five cases of invasive SCC. The only significant finding was the presence of malignant squamous epithelial cells in the latter. Since the background material in pronounced squamous epithelial atrophy/atrophic vaginitis mimics that present in invasive SCC on ThinPrep cytology, close attention must be paid to the cells present on the slide in order to render an accurate diagnosis.