Cervical ectropion is a condition in which the central (endocervical) columnnar epithelium protrudes out through the external os

External orifice of the uterus

The external orifice of the uterus is a small, depressed, somewhat circular aperture on the rounded extremity of the vaginal portion of the cervix. Through this aperture, the cervical cavity communicates with that of the vagina.The external orifice is bounded by two lips, an anterior and a posterior...

 of the cervix

Cervix

The cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall...

 and onto the vaginal portion of cervix

Vaginal portion of cervix

The vaginal portion of the cervix projects free into the anterior wall of the vagina between the anterior and posterior fornices vaginae.On its rounded extremity is a small, depressed, somewhat circular aperture, the external orifice of the uterus, through which the cavity of the cervix...

, undergoes squamous metaplasia

Squamous metaplasia

Squamous metaplasia refers to benign changes in the epithelial linings of certain organs within the body. These cells assume a more squamous morphology. Common sites for squamous metaplasia include the bladder and cervix. Smokers often exhibit squamous metaplasia in the linings of their airways...

, and transforms to stratified squamous epithelium. . Although not an abnormality, it is indistinguishable from early cervical cancer

Cervical cancer

Cervical cancer is malignant neoplasm of the cervix uteri or cervical area. One of the most common symptoms is abnormal vaginal bleeding, but in some cases there may be no obvious symptoms until the cancer is in its advanced stages...

, therefore, further diagnostic studies (e.g., Pap smear, biopsy) must be performed for a differential diagnosis.

Formation

The squamocolumnar junction, where the columnar secretory epithelium of the endocervical canal meets the stratified squamous covering of the ectocervix, is located at the external os before puberty. As oestrogen levels rise during puberty, the cervical os opens, exposing the endocerval columnar epithelium onto the ectocervix. This area of columnar cells on the ectocervix forms an area that is red and raw in appearance called an ectropion (cervical erosion). It is then exposed to the acidic environment of the vagina

Vagina

The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

 and, through a process of squamous metaplasia

Squamous metaplasia

Squamous metaplasia refers to benign changes in the epithelial linings of certain organs within the body. These cells assume a more squamous morphology. Common sites for squamous metaplasia include the bladder and cervix. Smokers often exhibit squamous metaplasia in the linings of their airways...

, transforms into stratified squamous epithelium.

Causes

Cervical erosion is a normal phenomenon, especially in ovulatory phase on younger women, pregnant women, and those taking the oral contraceptive pill which increases the total estrogen level in the body. It also may be a congenital problem by persistence of the squamocolumnar junction normally present in the intrauterine life. Additionally, it can be caused by scarring of the external os during vaginal intercourse.

Mucopurulent cervicitis may increase the size of the cervical ectropion.

Symptoms

Cervical ectropion can be associated with excessive but non-purulent vaginal discharge due to the increased surface area of columnar epithelium containing mucus-secreting glands. It may also give rise to post-coital (after sexual intercourse) bleeding as fine blood vessels present within the columnar epithelium are easily traumatized.

Treatment

Usually no treatment is indicated for clinically asymptomatic cervical ectropions. Hormonal therapy may be indicated for symptomatic erosion. If it becomes troublesome to the patient, it can be treated by discontinuing the oral contraceptive pill, or by using ablation treatment under local anaesthetic. Ablation involves using a preheated probe (100 degrees Celsius) to destroy 3-4mm of the epithelium. Observation and re-examination is necessary for 3 months after labour in post-partum erosion.