Cervical clear cell carcinoma (cCCC) constitutes an extremely rare subtype of cervical cancer. Consequently, its pathogenesis remains largely unknown, with no cell lines established from primary tumors. Here, we report the first establishment of cCCC organoids, from biopsy samples of a 23‐year‐old patient diagnosed with cCCC. By applying a protocol that we recently optimized for gynecological tumors, we were able to propagate a patient‐derived cell line (PDC) for more than 6 months as organoids. This PDC tolerated cryopreservation and proliferated either as spheroids or adherent cells, and developed xenografts in immunodeficient mice, ensuring robust utility as a cell line. Intriguingly, the resected tumor focally contained serous carcinoma (SC) in a tiny protruding lesion. Both organoids and derivative xenografts resembled the CCC component of the original tumor in histology, immunostaining profile, and genome‐wide copy number changes, including focal gain of MET. Genomic analysis revealed that both organoids and the CCC component harbored only a few mutations, of which 2 mutations were shared in common. In contrast, the SC component showed a mutator‐phenotype and prominent genome instability along with biallelic inactivation of TP53, but none of them were found in organoids or the CCC component. The PDC proved sensitive to major chemotherapeutic agents and MET inhibitors. These observations clearly indicated that the PDC, designated as YMC7, can be used as a novel cCCC cell line and provide novel insights into the pathogenesis of mixed cervical adenocarcinoma. As a valuable resource for rare cancer, it will likely contribute to investigations in many fields.

Cervical clear cell carcinoma (CCCC) is rare. This report describes the case of CCCC with a serous component. A 22‐year‐old woman presented with vaginal bleeding. A cervical tumor was discovered: pelvic magnetic resonance imaging revealed a tumor measuring 46 mm. Radical hysterectomy was performed based on the diagnosis of stage IB2 cervical cancer. After histological examination of the specimen revealed a coexisting invasive clear cell carcinoma (95%) and serous carcinoma (5%), five cycles of nedaplatin and irinotecan therapy were administered as postoperative adjuvant chemotherapy. Local recurrence in the vaginal vault was observed at 7 months after surgery. Radiation therapy and chemotherapy were administered. The patient is alive without evidence of recurrence at 26 months after surgery.