Cervical dysplasia is a precancerous condition in which abnormal cell growth occurs on the surface lining of the cervix, the opening between the uterus and the vagina. It is also called cervical intraepithelial neoplasia (CIN). Strongly associated with sexually transmitted human papillomavirus (HPV) infection, cervical dysplasia is most common in women under age 30 but can develop at any age.
Cervical dysplasia usually causes no symptoms, and is most often discovered by a routine Pap test. The prognosis is excellent for women with cervical dysplasia who receive appropriate follow-up and treatment. But women who go undiagnosed or who don't receive appropriate care are at higher risk of developing cervical cancer.
Squamous cell (epidermoid) carcinoma comprises approximately 90%, and adenocarcinoma comprises approximately 10% of cervical cancers. Adenosquamous and small cell carcinomas are relatively rare. Primary sarcomas of the cervix have been described occasionally, and malignant lymphomas of the cervix, primary and secondary, have also been reported.
Mild cervical dysplasia sometimes resolves without treatment, and may only require careful observation with Pap tests every three or six months. But moderate-to-severe cervical dysplasia -- and mild cervical dysplasia that persists for two years -- usually requires treatment to remove the abnormal cells and reduce the risk of cervical cancer.
Causes of Cervical Dysplasia
In many women with cervical dysplasia, HPV is found in cervical cells. HPV infection is common in women and men, and most often affects sexually active women under age 20.
In most cases, the immune system eliminates HPV and clears the infection. But in some women, the infection persists and leads to cervical dysplasia. Of the more than 100 different strains of HPV, more than one-third of them can be sexually transmitted, and two particular types -- HPV 16 and HPV 18 -- are strongly associated with cervical cancer.
HPV is usually passed from person to person during sexual contact such as vaginal intercourse, anal intercourse, or oral sex. But it also can be transmitted by any skin-to-skin contact with an infected person. Once established, the virus is capable of spreading from one part of the body to another, including the cervix.
Among women with a chronic HPV infection, smokers are twice as likely as nonsmokers to develop severe cervical dysplasia because smoking suppresses the immune system.
Chronic HPV infection and cervical dysplasia are also associated with other factors that weaken the immune system, such as treatment with immunosuppressive drugs for certain diseases or after an organ transplant, or infection with HIV, the virus that causes AIDS.
Risk Factors for Cervical Dysplasia
Persistent HPV infection is the most important risk factor for cervical dysplasia, especially moderate-to-severe cervical dysplasia.
In women, an increased risk of a persistent HPV infection is associated with:
Early initiation of sexual activity.
Having multiple sex partners.
Having a partner who has had multiple sex partners.
Having sex with an uncircumcised man.
Diagnosis of Cervical Dysplasia
Because a pelvic exam is usually normal in women with cervical dysplasia, a Pap test is necessary to diagnose the condition.
Although a Pap test alone can identify mild, moderate, or severe cervical dysplasia, further tests are often required to determine appropriate follow-up and treatment. These include:
Repeat Pap tests.
Colposcopy, a magnified exam of the cervix to detect abnormal cells so that biopsies can be taken.
Endocervical curettage, a procedure to check for abnormal cells in the cervical canal.
Cone biopsy or loop electrosurgical excision procedure (LEEP), which are performed to rule out invasive cancer. During a cone biopsy, the doctor removes a cone-shaped piece of tissue for lab examination. During LEEP, the doctor cuts out abnormal tissue with a thin, low-voltage electrified wire loop.
HPV DNA test, which can identify the HPV strains which are known to cause cervical cancer.