Passage of vaginal tissue in an non-pregnant adolescent

A 16-year-old female, with a history of spontaneous abortion 2 years ago, presented to the emergency department immediately after tissue expulsion vaginally (Figure 1). The patient had been placed on a high-dose depot of medroxyprogesterone acetate (DMPA) 4 weeks prior to presentation. Additionally, she had abdominal cramping and denied recent sexual activity, fever, or vaginal discharge. Her vital signs were normal. Complete Blood Count (CBC) and Comprehensive metabolic panel (CMP) were normal and serum human chorionic gonadotropin was <1 MIU/mL. Pelvic ultrasound demonstrated trace non-specific fluid (Figure 2). The diagnosis was confirmed histologically.

Decidual cast (DC) is a gynecological phenomenon in which the entire lining of the uterine cavity is shed in one piece, resembling the shape of the uterus.^{1, 2} This condition can be quite alarming due to its dramatic presentation and can be accompanied by significant pain and heavy bleeding. Women may report cramping similar to or more intense than typical menstrual cramps, alongside the expulsion of a fleshy mass. The pathology involves excessive buildup and subsequent detachment of the decidualized endometrial lining under the influence of progesterone.^{2, 3} Hormonal contraceptives, particularly those containing progesterone such as DMPA can predispose to DC.^{1, 4, 3} Diagnosis is clinical, supported by history and physical examination, and may be confirmed by histological examination if the cast is retained for analysis. Our patient's histology showed benign decidualized endometrial tissue with exogenous progesterone effects. Treatment focuses on pain control for abdominal cramping, and patient may continue to use the contraceptive method without further episodes of DC formation.2,5