Introduction :
The transverse vaginal septum or vaginal septum is a rare abnormality of the female genital tract with an incidence of between 1/2100 and 1/72001. The most common etiology is a defect in the fusion and/or channelling of the urogenital sinus and Mullerian conductors2. The transverse vaginal septum can develop anywhere in the vagina, and its most common locations are in the lower part of the vagina according to the latest publications, so 72% of the septums are in the lower part of the vagina, 22% in the central part and 6% in the upper part of the vagina3. These septa are usually no more than 1 cm thick and usually have an eccentric perforation which allows for vaginal discharge. These structural obstacles can completely obstruct the vagina and can cause haematocolpos associated with cyclic pelvic pain shortly after menarche in adolescent girls. Haematocolpos is defined as an accumulation of menstrual blood in the vaginal cavity4. The diagnosis of a vaginal septum is based on a careful clinical gynaecological examination and especially on ultrasound scan via the abdomen or transrectal or even transperineal ultrasound and in more complex cases an MRI scan. The treatment is surgical and should be carried out as early as possible, as its management after puberty is associated with a high rate of vaginal stenosis5.