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Introduction: Adenosarcoma is a rare uterine tumor composed of benign epithelial and malignant stromal elements. In 20% of cases stroma contains heterologous elements (usually from stratified muscle type). Association between Tamoxifen usage (exogenous strogen) or ovarian thecoma (endogenous strogen) and occurance of this tumor has been reported. This is a case report of a uterine Adenosarcoma. Case: The patient was a 45 years old woman with history of 16 years OCP use who was admitted with a uterine mass and undergone total hysterectomy. Microscopic assessment of slides, stained by H&A, was indicator of Adenosarcoma with cartilage heterologous elements. Conclusion: Uterine Adenosarcoma is a rare tumor. Although there is a few reports of cartilage heterologous elements in uterine Adenosarcoma, this case had multiple cartilage points in stroma. Also in this case, the coexistance of this tumor with long- term OCP use was considerable.