Objective: Decidual cast in other words membranous dysmenorrhea is a rare entity. Hereby, we report the first infected case caused by drospirenon containing contraceptive use and managed successfully by hysteroscopy.
 Case presentation: A13 year-old girl started on drospirenon containing contraceptive theraphy since her menarche resulted in menorrhagia and anemia that requires transfusion. On follow up, she developed a partially discharged infected mass revealed to be a decidual cast on pathological review.
 Discussion: Membranous dysmenorrhea occurs more frequently in the adolescent and young adult population. All cases in this review were on hormonal theraphy except one occured spontaneously. Cast formation of the immature uterus after menarche is an exaggerated response to dose-independent increased progestin levels.
 Conclusion: We conclude that diagnosis of decidual cast/membranous dysmenorrhea should be kept in mind for colicky pain with bleeding of adolescents under hormonal contraceptive therapy and partially discharged cases may be managed successfully by hysteroscopy.