Interpretation of Endocervical Cells With Gastric-Type Mucin on Pap Smears A Proposal for a Cytologic Category "Atypical Endocervical Cells With Gastric-Type Mucin"

Objectives: Early detection of endocervical adenocarcinoma is especially important for cancers that are human papillomavirus (HPV) negative. We investigated the clinicopathologic significance of yellow gastric-type mucin observed on Papanicolaou smears. Methods: We described "atypical endocervical cells with gastric-type mucin" (AEC-GAM) when yellow mucin was observed in endocervical cells. We retrieved AECGAM samples from 58,752 cervical smears performed at Yamanashi University Hospital during our study period and reviewed clinical, cytologic, and pathologic features. Results: We detected AEC-GAM in 172 (0.29 %) smears from 65 patients, and 41 of these 65 patients were histologically diagnosed with lobular endocervical glandular hyperplasia (LEGH) (43%) or pyloric gland metaplasia (20%). The prevalence of adenocarcinoma was 25% (7/28) in LEGH cases and 11% (7/65) in AECGAM smears. Conclusions: Yellow mucin is a diagnostic clue for endocervical glandular lesions with gastric differentiation. We recommend describing AEC-GAM on cytologic reports to improve cytologic screening for HPV-negative cervical cancers.