BACKGROUND In the 18th century, Morgagni described membranous dysmenorrhea as the sudden and complete detachment of the decidua during menstruation. This causes intense and painful contractions of the myometrium, aggravated by the expulsion of tissues produced by the decidualization of the endometrium. It is a rare pathology associated with oral contraceptives, ectopic pregnancies, abortions, and natural cycles, with consequent thickening and endometrial decidualization with molding of the tissue of the uterine cavity of membranous appearance. The definitive diagnosis is made by histopathological examination. CASE REPORT A 43-year-old female patient came for urgent consultation for an acute picture of severe pain in the lower abdomen, radiating to the genital area with transvaginal bleeding of 2 h of evolution. She had no significant past medical history. A transvaginal ultrasound was performed and showed an unchanged endometrial cavity. A vaginal examination revealed a foreign body of soft consistency; therefore, a speculum examination was performed, which showed tissue of endometrial origin located in the cervical canal of a reddish spongy texture. The tissue was removed, thus improving the symptomatology, and was sent to the pathological anatomy service for histopathologic diagnosis. CONCLUSIONS Membranous dysmenorrhea is a rare gynecologic disorder with only a few documented cases. According to other case reports, our patient's case, at age 43 years, was an atypical presentation. The clinical features and association with this pathology allowed the diagnosis and its confirmation by histopathological examination.