Definition A popular term for a nonspecific finding in Pap smears of the uterine cervix consisting of inflammation, cellular debris, and necrosis, as seen in infections with Gardnerella vaginalis or Trichomonas spp, pregnancy, post-partum, post-menopause, oral contraceptive use, and cervical cancer
Note: Dirty backgrounds are less common in cytology specimens obtained by liquid based techniques
Definition A term of art for the karyorrhectic debris typically associated with ulcerated and acutely inflammed mucosa, is a soft criterion that provides the pathologist with some comfort that he/she is dealing with a malignancy. The image is that of a conventional smear of a pleural fluid with a dirty background, strongly suggestive of malignancy.
Reference J Cytology 2012; 29:11-15