Atypical squamous cells of undetermined significance: analysis of microbiology, cytological criteria and clinical conduct.

Aims: To differentiate between two types of atypical squamous cells of undetermined significance (ASCUS): probably neoplastic (PN) or probably reactive (PR), and, in accordance with the recommendations on screening protocols of the Emilia-Romagna Region (PSRER), Italy, to define the best management to follow and the prognosis. Furthermore, the associations between ASCUS and infectious agents and human papillomavirus (HPV) were evaluated.

Methods: Fifty-eight ASCUS smears were reviewed and sorted; if a diagnosis of ASCUS was confirmed, the smear was classified as PR or PN, and the PSRER group was identified. Then, colposcopy was performed with checks for infectious agents (culture evaluation with cytological or clinical criteria) and HPV (hybrid capture).

Results: The ASCUS frequency was 3.96%. Of the 58 cases, 33 (56.9%) were diagnosed as ASCUS on review, of which 15 cases were PN and 18 were PR, while 23 (39.7%) smears were normal and 2 (3.4%) showed cervical intraepithelial neoplasia (CIN). There was a higher frequency of bacterial vaginosis (BV) and HPV in ASCUS PR patients compared with normal cytology, and a higher frequency of CIN in ASCUS PN patients compared with normal controls (P < 0.05). By grouping ASCUS 1 and 3, we observed a higher frequency of CIN and of high-grade colposcopy findings compared with ASCUS 2 and 4 (P < 0.05). From the 23 cases not found to be ASCUS, 18 (87.5%) had normal cytology and colposcopy results on the first follow-up.

Conclusions: Classification of ASCUS as either PN or PR helps in clinical conduct and prognosis, because a higher frequency of CIN is found in ASCUS PN. ASCUS subdivisions, based on PSRER and colposcopy, may facilitate the clinical conduct because ASCUS 1 and 3 with high-grade colposcopic findings proved to be related to the presence of CIN. We propose that initial ASCUS cytology be reviewed, and if it is confirmed, colposcopy should be performed. For those cases found to be normal on review of the cytology results, it is suggested that a cytological check-up be carried out every 6 months.