p16<sup>INK4a</sup> and ProEx C Immunostains Facilitate Differential Diagnosis of Hyperchromatic Crowded Groups in Liquid-Based Papanicolaou Tests with Menstrual Contamination

Abstract

p16(INK4a) and ProEx C are sensitive markers for identifying significant lesions in Pap test specimens with menstrual contamination. Patchy/mosaic staining may be seen in benign endometrial tissue with tubal metaplasia, but strong, diffuse staining likely indicates HSIL or carcinoma. These findings can be helpful in interpreting hyperchromatic crowded groups in menstrual Pap specimens. Further study may be prudent, being aware of the small study group.