{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,17]],"date-time":"2025-12-17T09:03:51Z","timestamp":1765962231917,"version":"3.48.0"},"reference-count":32,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,12,17]],"date-time":"2025-12-17T00:00:00Z","timestamp":1765929600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:p>Endometriomas, commonly known as ovarian chocolate cysts, are a prevalent condition in women of reproductive age. They are cysts formed by the ectopic growth of endometrial tissue within the ovary, often leading to dysmenorrhea and infertility. Dienogest is a first-line medication for the long-term management of endometriomas, control of associated pain, and prevention of postoperative recurrence. A 34-year-old woman presented to our hospital with dysmenorrhea and was diagnosed with an endometrioma. She subsequently commenced dienogest treatment for a total duration of thirty-two months. During this period, the cyst gradually decreased in size and eventually became undetectable. However, a follow-up ultrasound indicated the recurrence of the endometrioma after twenty-seven months. Five months later, a subsequent ultrasound revealed papillary growth with internal blood flow within the ovarian endometrioma. The patient underwent immediate surgical intervention. The postoperative pathology indicated a borderline clear cell tumor. Consequently, the patient promptly underwent comprehensive staging surgery, with the final pathology confirming no residual tumor. This case demonstrates that despite long-term and effective dienogest treatment, endometriomas retain the potential for malignant transformation. Therefore, regular monitoring during treatment and prompt intervention upon suspicion of malignancy are indispensable.<\/jats:p>","DOI":"10.3389\/fonc.2025.1732665","type":"journal-article","created":{"date-parts":[[2025,12,17]],"date-time":"2025-12-17T09:00:36Z","timestamp":1765962036000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Borderline ovarian clear cell tumor arising from endometriosis during long-term dienogest therapy: a case 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