Tehran University of Medical Sciences Journal of Family and Reproductive Health 1735-8949 15 2 2021 06 20 125 129 Amrita Talwar Department of Pathology, Postgraduate Institute of Medical Sciences, Ram Manohar Lohia Hospital, New Delhi, India Pushpanjali Behera Department of Pathology, Postgraduate Institute of Medical Sciences, Ram Manohar Lohia Hospital, New Delhi, India Arvind Ahuja Department of Pathology, Postgraduate Institute of Medical Sciences, Ram Manohar Lohia Hospital, New Delhi, India Bani Sarkar Department of Obstetrics & Gynecology, Postgraduate Institute of Medical Sciences, Ram Manohar Lohia Hospital, New Delhi, India Ravi Phulware Department of Pathology, All India Institute of Medical Sciences, Rishikesh, India 2020 12 01 2021 03 13 Objective: Endometrial cancer (EC) is the most commonly diagnosed malignancy and has the second-highest mortality rate among gynecological cancers. Adenomyosis is well-known for abnormal uterine bleeding and is a widely reported entity; however, an EC arising from the adenomyosis is a rare event; even rarer is the occurrence of serous endometrial carcinoma. Case report: A 60-year post-menopausal female presented with post-menopausal bleeding. Subsequently, she underwent a hysterectomy, which showed atrophic and cystic endometrium with extensive adenomyosis and atypical endometrial glands, which are diffusely P53 positive with intervening negative benign and focally positive dysplastic endometrial glands. A final diagnosis of serous endometrial carcinoma arising from adenomyosis was rendered. In a table format, previously reported serous endometrial carcinoma Arising cases from adenomyosis using PubMed search had been described. Conclusion: Serous endometrial carcinoma arising from adenomyosis (<20 cases reported) and has a slightly more dismal prognosis than those deriving from the endometrial cavity. Hence, this case report highlights the occurrence, rarity, and importance of such an entity. https://jfrh.tums.ac.ir/index.php/jfrh/article/view/1622 https://jfrh.tums.ac.ir/index.php/jfrh/article/download/1622/563