Atypical Microglandular Hyperplasia of the Cervix With a Deceptive Pseudoinvasive Pattern: A Report of Two Patients Mimicking Malignancy and a Review of the Literature

Objective Atypical microglandular hyperplasia (MGH) of the cervix with a pseudoinvasive pattern is a well-known diagnostic pitfall. This study reviews this entity and uses two initially misdiagnosed lesions to illustrate the key morphologic, immunohistochemical, and molecular features that distinguish atypical MGH from its malignant mimics. The aim is to provide a practical diagnostic framework to improve diagnostic accuracy and prevent patient overtreatment. Methods We conducted a retrospective clinicopathological analysis of two patients with atypical cervical MGH exhibiting a pseudoinvasive pattern. Diagnosis was confirmed through comprehensive histological examination, supplemented by immunohistochemistry, special staining (Alcian blue–periodic acid–Schiff), and molecular testing for KRAS mutations. Clinical follow-up was obtained, and relevant literature was reviewed. Results The patients were a 54-year-old woman and a 47-year-old woman presenting with irregular vaginal bleeding. Both lesions were initially misdiagnosed at outside institutions (as endometrial adenocarcinoma and usual-type endocervical adenocarcinoma, respectively). Histological review revealed nearly identical features: a complex proliferation of small, crowded microglandular structures, intermixed with irregular solid nests and cords of cells with eosinophilic cytoplasm, haphazardly dispersed in a loose, myxoid stroma. Occasional signet-ring-like cells were noted. Immunohistochemically, the lesions were positive for ER (estrogen receptor, official symbol ESR1 ), showed focal p16 ( CDKN2A ) positivity, a wild-type p53 ( TP53 ) pattern, and a low Ki-67 ( MKI67 ) index (≈2%). They were negative for CEA ( CEACAM5 ), with retained expression of PTEN and PAX2. Alcian blue–periodic acid–Schiff staining was positive. No KRAS mutations were detected. Conclusion Cervical MGH is a benign lesion, but its atypical variant with a pseudoinvasive pattern is a great mimicker of adenocarcinoma. A definitive diagnosis requires the integration of characteristic histomorphology with a confirmatory immunohistochemical profile. Pathologists must be familiar with this entity to avoid misdiagnosis and ensure appropriate clinical management.