[Atypical forms of microglandular hyperplasia of the cervix: a clinicopathological analysis of 29 cases]

Objective: To investigate the clinicopathological characteristics, immunophenotype and differential diagnosis of atypical forms of microglandular hyperplasia of the cervix (AMGH). Methods: A total of 29 cases of AMGH diagnosed at the Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China from January 2010 to December 2024 were analyzed. Relevant clinical and pathological data of the patients were collected using the electronic medical record system and medical records copied from the outside hospitals. The patients were followed up. Results: Among the 29 cases, 28 were consultation cases, 22 (79%) of the 28 cases were considered as glandular neoplastic lesions by the original institutions. The nature of the lesion was uncertain in 1 case, the diagnosis was suspicious for AMGH in another 1 case, and only 4 cases were clearly diagnosed as AMGH. The median age of the 29 patients was 44 (43, 48) years. Eighteen (62%) of the 29 cases presented as cervical polyp. Twelve of the 16 tested cases were negative for human papillomavirus. The pathological presentation was complex and diverse, including solid, trabecular, cribriform, and papillary patterns, forming pseudo-invasive structures. The glandular epithelium and proliferating reserve cells had diverse morphologies, which presented with abundant eosinophilic cytoplasm or clear cytoplasm. Signet-ring or hobnail cells were also seen. The nuclear atypia was mild, with 0-7 mitotic figures per 10 HPF. Immature squamous metaplasia was noted. The stroma showed edema, myxoid change and hyaline degeneration, accompanied by infiltration of acute and chronic inflammatory cells. Immunohistochemistry demonstrated that p16 was negative in 8/16 of the cases or patchy positive in the other 8/16, Ki-67 positive rate was less than 10% in all 16 cases, p53 was wild phenotype (9/9), and carcinoembryonic antigen was negative in 4/5 cases and focally positive in 1/5 cases, while p63 was positive in 6/9 of the tested cases. Conclusions: AMGH is a benign non-neoplastic lesion of the cervical glands. Half of the cases occur in perimenopausal or postmenopausal women, often presenting as polypoid hyperplasia or localized cervical thickening/elevation with a friable, fragile texture. Microscopically, it may show a pseudoinvasive pattern, making it prone to misdiagnosis as a malignant lesion. Thus, differentiation from cervical adenocarcinoma, clear cell carcinoma and microglandular endometrioid carcinoma is required. Integration of clinical history, immunohistochemistry and molecular testing may aid in the differential diagnosis.