Accuracy and false-positive rate of the cytologic diagnosis of follicular cervicitis: observations from the College of American Pathologists Pap Educational Program.

ABSTRACT

CONTEXT Follicular cervicitis is usually easily identifiable on Papanicolaou (Pap) tests; however, historically, follicular cervicitis is reported to lead to false-positive diagnoses of epithelial cell abnormalities. OBJECTIVES: To assess participant responses in the College of American Pathologists (CAP) Pap educational program (CAP-PAP) to determine the accuracy and false-positive rate of follicular cervicitis cases. Design.-We performed a retrospective review of 4914 participant responses for gynecologic cytology challenges with the reference diagnosis of follicular cervicitis during 11 years (2000-2010) from CAP-PAP. Reference diagnosis category, false-positive rates by participant type (laboratory, cytotechnologist, pathologist), and preparation type (conventional smears, ThinPrep) were analyzed. RESULTS: Of the total 4914 general category responses, 4368 (88.9%) were benign while 546 (11.1%) responses were epithelial cell abnormalities (false positives). Of benign responses, only 2026 (46.4%) were an exact match to follicular cervicitis. Adenocarcinoma and high-grade squamous intraepithelial lesion were the most common diagnoses chosen as a false-positive interpretation (42.3% and 20.1%, respectively). Participant type was significantly associated with false-positive interpretations (laboratory 19.2%; cytotechnologist 11.1%; pathologist 7.9%; P < .001). ThinPrep was also significantly associated with false-positive results as compared to conventional smears (12.2% versus 3.6%; P < .001). CONCLUSIONS: In an interlaboratory comparison educational program, follicular cervicitis is difficult to interpret accurately and represents an important cause of false-positive responses. Follicular cervicitis may mimic adenocarcinoma or high-grade squamous intraepithelial lesion, particularly in liquid-based preparations. The diagnostic difficulty most likely arises from the lymphocytes being less conspicuous in the background as well as their tendency to aggregate in ThinPrep as compared to conventional smears.