BACKGROUND: In 2002, the Brazilian Nomenclature for Reporting Cervical Cytological Diagnosis was revised. A category of atypical epithelial cells of undetermined significance (AUS) and another (sub-classification) of atypical epithelial cells of undetermined significance and undetermined origin (AUSUO) were introduced. Like atypical squamous cells of undetermined significance (ASCUS) and atypical glandular cells of undetermined significance (AGUS), the diagnostic category AUSUO is controversial. Despite controversies, no previous national study had investigated its importance. OBJECTIVES: This study has the main objective of investigate the importance of the diagnostic category AUSUO. Another purpose is to contribute to spread the Brazilian Nomenclature for Reporting Cervical Cytological Diagnosis, by publishing it entirely. MATERIALS AND METHODS: The study resulted from the contribution of two private pathology and cytopathology laboratories. Cases diagnosed as ASCUS or AGUS with follow-up were selected from archives of cytopathology exams, collected from the period between 2000 and 2004. In total, 30 cases were selected and revised, being identified cytological diagnostic fields of ASIOI, ASCUS and AGUS. RESULTS: After revision, from the 30 cases, 26 were selected for the study. Among these, 19 presented cytological fields with diagnosis of only ASCUS and/or AGUS and were used as a control group. Only seven cases contained fields compatible with AUSUO, 4 (57,1%) were associated with AGUS; 1 (14.3%) with ASCUS; 1 (14.3%) with both; and 1 (14.3%) had no alterations compatible with ASCUS and/or AGUS. CONCLUSIONS: The AUSUO cases showed a strong association with AGUS and glandular alterations in histology. Most of these cases corresponded to reactive and benign alterations, except for one case of endocervical dysplasia and one case of in situ adenocarcinoma. The AUSUO diagnosis is a rare finding, and after a careful revision of the pap smears, in the majority of the cases, fields of AGUS are found. It’s worthwhile to emphasize the strong association between this diagnosis and poor fixed areas in the pap smears. New studies will be necessary to confirm our findings. Based in this first approach to this issue, we suggest that the persistence of this term should be questioned in the forthcoming revisions of our national nomenclature for reporting cervical cytological diagnosis.
Atypical squamous cells of undetermined significance (ASCUS); Atypical glandular cells of undetermined significance (AGUS); Brazilian Nomenclature for Reporting Cervical Cytological Diagnosis; Bethesda System; Cytohistological correlation