Abstract: Objective To conduct a case study on invasive stratified mucin-producing carcinoma （ISMC）, a newly named human papillomavirus （HPV）-related cervical mucinous adenocarcinoma, and provide clinical and pathological data for this rare disease. Methods Three cases of ISMC were retrospectively analyzed, and the pathological characteristics, immunophenotype, HPV genotyping, and prognosis were explored in combination with relevant literature. Results ISMC tumor cells exhibited a diversity of structural patterns and cell morphology. The cytoplasm of the tumor cells contained different amounts of mucus, and neutrophil infiltration could be seen around the nests and intratumorally. Apoptotic bodies and mitosis were found in all three cases. Immunohistochemistry showed p16 and CK7 were diffuse and strong （+）, while PAX8, p40, and CK5/6 were slight （+） around the nests . Conclusion ISMC is a rare, HPV-associated adenocarcinoma with a broad morphological spectrum. The unique expression patterns of PAX8, CK5/6, and p40 can be used as effective markers for ISMC diagnosis. ISMC has a poor prognosis, and it is important that even if a small amount of ISMC components are detected, their percentages should be noted in the diagnosis.

Key words: Invasive stratified mucin-producing carcinoma, Histological feature, Immunohistochemistry