Rapid Progression and Poor Prognosis in Endometrioid Ovarian Cancer Arising from Endometrioma: A Case Report

Endometriosis is linked to an increased risk of endometrioid ovarian cancer, though malignant transformation is rare. We report a 35-year-old nulliparous woman with a 12-year history of endometriosis who developed endometrioid ovarian cancer two months after her last surgery. Histological examination initially showed no malignancy, but subsequent immunohistochemical analysis confirmed cancer. The patient underwent surgery followed by six cycles of platinum-taxane chemotherapy. This case underscores the need for thorough assessment in rapidly progressing endometriosis.