What is High-Grade Squamous Intraepithelial Lesion (HGSIL)?
High-grade squamous intraepithelial lesion (HISL), a type of cervical dysplasia detected by microscopic analysis of cell samples taken from the cervix, refers to the moderately to severely abnormal-appearing cervical cells on a Pap smear. Cervical dysplasia refers to the occurrence of pre-malignant or precancerous cells in the cervix and opening of the uterus. With this regard, HSIL indicates moderate dysplasia to severe neoplasia of the cervical cells that may mean carcinoma in situ.
HSIL is different from low-grade squamous intraepithelial lesion (LSIL) in which the former have more defined changes in the shape and size of the cervical cells. LSIL only involves the appearance of early changes in the shape and size of the cells and is often associated with the presence of the human papilloma virus or genital warts.
HSIL may eventually lead to invasive cancer of the cervix when management is not instituted. As the most severe form of HSIL, carcinoma in situ is considered stage 0 of cervical cancer but may not indicate the presence of cervical cancer. The presence of HSIL should be treated to prevent the development into cervical cancer.
HSIL can be seen in various areas such as the esophagus, cervix, vagina, and vulva where there are squamous epitheliums.
Any detection of HSIL requires further tests to evaluate the presence of cancer. Only 2% of patients with HSIL have invasive cancer; however, up to 20% with HSIL will develop cancer if it is left untreated. To prevent HSIL from developing into cancer, the precancerous cells are removed or destroyed.
Symptoms of HSIL
The appearance of cervical dysplasia such as HSIL usually does not result in signs and symptoms. The only manifestation of the condition is the microscopic changes that happen in the cervical cells evident on microscopic examination. When HSIL occurs along with cervical cancer, there are symptoms associated with cervical malignancy such as:
- pain in the area
- bleeding after intercourse
- vaginal bleeding
- abnormal vaginal secretions
Causes of HSIL
The cause of any type of cervical dysplasia such as HSIL is similar to the risk factors for cervical cancer which includes:
Human papilloma virus (HPV)
Genital warts or HPV infection, one of the most common sexually transmitted diseases which is sometimes asymptomatic, can lead to HSIL. HPV usually affects young women aged 15 to 25 years old. Most women become infected with HPV without knowing it. HPV usually resolves spontaneously without any treatment, but it may have caused cervical dysplasia by that time if untreated. Recurrent HPV infection is commonly associated with cervical dysplasia and cervical cancer. Since HPV is transmitted through sexual contact, preventing it involves having only one sex partner and ensuring safe sex practices all the time. Smoking or a weakened immune system can increase the risk of HPV infection.
Diagnosis of HSIL
Diagnostic tests for HSIL involves undergoing Pap smear. Pap smear or Pap test is done during pelvic examination where a speculum is inserted to collect samples of the cervical mucus. The mucus is then smeared and examined under the microscope to determine the type of cervical dysplasia.
When HSIL is observed, further tests are done to evaluate the presence of cervical cancer. These include:
Colposcopy, which involves the use of a microscope or colposcope to study or visualize the cervix, helps identify specific areas of cervical dysplasia and can check the totality of the cervix. The abnormal cells may be removed at the time of colposcopy to prevent further spread. This management is called “see and treat.” Colposcopy may last for one hour, and the results are examined to determine the extent of abnormality.
When suspicious areas are seen during colposcopy, a biopsy may be done to check if the cells are benign or malignant. Abnormal dysplasia in the cervix as seen in biopsies is termed cervical intraepithelial neoplasia (CIN). CIN is further classified into:
- CIN 1- This involves the presence of dysplasia in 1/3 of the cervical epithelium.
- CIN 2- This involves the presence of dysplasia in 2/3 of the cervical lining and represents a more serious case of cervical dysplasia.
- CIN 3- This can be categorized as carcinoma in situ in which the dysplasia affects more than 2/3 of the cervical lining.
HPV testing is also performed in women to detect the presence of HPV infection.
Treatment of HSIL
The presence of cervical intraepithelial neoplasia (CIN) in biopsy may prompt treatments which include:
Loop electrosurgical excision procedure (LEEP)
This surgical procedure involves the excision of abnormal cells through the introduction of an electric current through a wire loop in the cervix. When HSIL is diagnosed in pregnant women, LEEP may be postponed and done after delivery because it can cause premature labor or spontaneous abortion in the first trimester. Progression of HSIL is usually slow during pregnancy so LEEP may be done later.
Conization is another approach for the treatment of HSIL. This involves the removal of a cone-shaped tissue from the cervix to obtain deeper layers of abnormal cells for laboratory testing. This is usually done during biopsy and is also called cone biopsy.
This surgical procedure involves the use of very cold substances to freeze the abnormal cervical cells. After freezing, the area exposed is usually removed.
This procedure involves the use of laser beams to destroy and remove the abnormal cells.
After the removal or excision of the abnormal cervical cells, follow-up check-ups are needed to ascertain that no cervical cancer or another HSIL occurs. Cells may still become abnormal despite the surgical removal and may progress to cervical cancer when not detected early. Follow-up care includes:
- Pap smear with colposcopy every 6 months in one year followed by annual pap smears when there are no abnormal cells seen.
- Pap smear and colposcopy every 6 months when abnormal cells are seen after the first year of follow-up.
Prognosis of HSIL
The presence of HSIL should not be mistaken for the presence of cancer. HSIL has a good prognosis when treatments are instituted. In fact, only 20 percent of cases progress to cervical cancer without treatment, which means that early management for HSIL will not eventually lead to cervical malignancy.
Updated by Minna on 25/11/2012.