Introduction. This article presents a rare case of synchronous invasive squamous cell carcinoma (SCC) and clear cell adenocarcinoma (CCA) of the cervix, characterized by mismatch repair (MMR) deficiency and positive PD-L1 expression.
Case Presentation. A 47-year-old postmenopausal woman, presenting with lower abdominal pain and metrorrhagia, was diagnosed with a collision tumor. Histological analysis revealed distinct tumor components, with SCC and CCA both showing HPV16 positivity and exhibiting MMR deficiency. Immunohistochemical studies demonstrated strong p16 expression in both components, while PD-L1 was expressed in both tumors. The loss of MMR proteins PMS2 and MLH1 in both tumor types raises questions about the role of HPV and MMR defects in tumor development.
Conclusions. This case contributes to the understanding of the pathogenesis of collision tumors of the cervix, highlighting the potential for immunotherapy in recurrent or metastatic cases due to PD-L1 expression and MMR deficiency.
Keywords. Mismatch repair proteins, cervix, clear cell, adenocarcinoma.
Full text sources https://doi.org/10.31688/ABMU.2025.60.1.11
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Address for correspondence:
Sylvia NIKOLAEVA GENOVA
Department of General and Clinical Pathology, Medical University – Plovdiv,
Medical Faculty Plovdiv, Bulgaria
Address: 15 A, V. Aprilov Blvd., Plvodiv, Bulgaria
E-mail: sylvia_genova@abv.bg; Phone: 359 887 198 557
