Imperforate hymen with hematocolpometra.
A 15-year-old premenarchal girl presented with a 4-day history of increasing abdominal pain. Her medical history was unremarkable, and she reported that she had never been sexually active. Physical examination revealed a palpable, nontender, nonpulsatile midline mass extending from the pelvis to the umbilicus. The patient declined a vaginal examination. Abdominal ultrasonography revealed a large pelvic mass of uncertain origin. The uterus could not be identified ultrasonographically. Computed tomographic images of the pelvis showed a hyperdense, nonenhancing, fluid-filled pelvic mass measuring 25 cm by 11 cm by 12 cm that was causing substantial compression of the bladder . A tubular structure at the superior pole of the mass was identified as the uterus. The patient was given a presumptive diagnosis of hematocolpometra (accumulation of menstrual blood in the vagina and uterus). Subsequent vaginal examination revealed a thickened imperforate hymen. After hymenotomy, two liters of coagulated blood drained from the vagina and uterus. The patient was discharged after 3 days without pain or vaginal bleeding. (adapted from NEJM)
Image adapeted from NEJM (link)