ProExC triage of atypical glandular cells on liquid-based cervical cytology specimens

Morphologic distinction between atypical glandular cells not otherwise specified (AGC-NOS) and AGC-favor neoplasia (AGC-FN) can be difficult. Distinction between these entities is important as the American Society for Colposcopy and Cervical Pathology 2006 consensus guidelines state that management of AGC-NOS differs from that of AGC-FN. The objective of this study was to determine the potential role of ProExC immunocytochemical triage of AGC-NOS.

Cytopathology records from a pathology practice were reviewed from January 2006 to December 2009 to identify AGC-NOS liquid-based Pap smears with subsequent biopsy correlation. Archival slides were examined, and ProExC immunocytochemistry was performed. The AGC groups were assessed for nuclear staining, and results were correlated with subsequent biopsy findings.

Twenty-eight AGC-NOS cases with biopsy correlation were identified: 13 with subsequent high-grade neoplastic or malignant (positive) diagnoses and 15 with benign diagnoses. Of 13 AGC-NOS cases with positive diagnosis, 10 were ProExC-positive and 3 were ProExC-negative (metastatic tumors from distant sites). Of 15 AGC cases with benign follow-up, 13 were ProExC-negative and 2 were ProExC-positive (sensitivity, 77%; specificity, 87%). For patients with cervical intraepithelial neoplasia or carcinoma originating from the female genital tract, 100% (10/10) were ProExC-positive (sensitivity, 100%; specificity, 87%).

Results suggest that ProExC-positive AGC-NOS may be classified as AGC-FN. Although positive immunocytochemical staining for ProExC requires management similar to AGC-FN, negative staining does not rule out malignancy such as metastatic tumor. Management for ProExC-negative AGC-NOS cases should proceed according to the current guidelines for AGC-NOS.