imperforate hymen

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Imperforate hymen is a congenital condition in which the hymen lacks a normal opening.

Epidemiology

It happens in 0.1% of the female population, usually an isolated finding.

Clinical presentation

Primary amenorrhea with cyclic lower abdominal pain during menarche age. An imperforate hymen can be diagnosed at physical examination upon identification of a bulging, bluish membrane that allows positive transillumination at the introitus; consequently, imaging is rarely indicated.

Pathology

Failure of the recanalization process of the distal end of the vagina. The hymen indicates the junction between the urogenital sinus and sinovaginal bulb. Imperforate hymen occurs due to a failure of recanalization of this membranous vestige.

Radiographic features

Ultrasound

The usual initial imaging modality of diagnosis, it shows a distended fluid-filled vagina (hematocolpos) and uterus (hematometra) with internal echoes representing hemorrhage of various ages.

MRI

Signal changes follow subacute bleeding episodes and the blood products in hematometrocolpos:

  • T1: hyperintense endometrial fluid extending down to the level of the hymen
  • T2: hypointense endometrial fluid extending down to the level of the hymen