Uterine adenosarcoma arising from a subserosal adenomyoma: A case report

•Adenosarcoma is a rare tumor of the uterus and cervix occuring mostly in post-menopausal women.•Our patient was a 37-year old nullipara presenting with lower abdominal pain and backache.•She was diagnosed as a case of multiple leiomyomata and proceeded for myomectomy.•Intraoperative findings raised suspicion of malignancy.•She underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Histology confirmed the diagnosis.