Imperforate hymen is a congenital condition in which the hymen lacks a normal opening.
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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
Treatment and prognosis
The standard treatment is surgical. Simple incision should be avoided due to increased risk of ascending infection and sepsis 3.