Liquid-based Cytological Features of Adenocarcinoma Not Otherwise Specified, Extrauterine Adenocarcinoma, and Other Malignant Neoplasms of The Uterine Cervix: A 5-year Single-institutional Experience With 30 Consecutive Patients.

Background/aim: The adenocarcinoma (ADC) and other malignant neoplasm (OMN) terminologies of The Bethesda System represent various histological types of uterine and extrauterine malignancies. This study aimed to clarify the incidences of ADC not otherwise specified (ADC-NOS), ADC extrauterine (ADC-EXT), and OMN in our institution and describe their characteristic cytomorphological features.

Patients and methods: We searched the database to identify all patients diagnosed with carcinoma, including those diagnosed through cervical liquid-based cytology (LBC), between January 2019 and December 2023. The electronic medical records and all available slides were reviewed.

Results: Overall, 30 of the 149,197 (0.02%) patients were diagnosed with ADC-NOS, ADC-EXT, and OMN. All three groups included various histological types of both gynecological and non-gynecological origin. More than two-thirds (23/30; 76.7%) were of uterine origin, but seven patients had metastatic carcinoma of extrauterine organ origin, including the ovary, lung, stomach, breast, colon, urethra, and pancreas. In all patients, the cytological features were concordant with the histological features.

Conclusion: In LBC, ADC-NOS does not only encompass uterine cervical tumors, but also various types of extrauterine malignancies. ADC-EXT and OMN also represent both extrauterine and uterine tumors. Awareness of the morphological features observed in LBC samples of non-gynecological malignancies may be helpful in obtaining the correct diagnosis.