Atypical squamous cells, cannot rule out HSIL - Cervix -

This article will help you read and understand your pathology report for atypical squamous cells, cannot rule out HSIL (ASC-H).

by Adnan Karavelic, MD FRCPC, reviewed on April 27, 2020

ASC-H

Quick facts:

  • Atypical squamous cells, cannot rule out HSIL (ASC-H) means that abnormal looking cells were seen in your Pap test.
  • It is a preliminary result and not a final diagnosis.
  • This result raises the possibility that a pre-cancerous disease called high grade squamous intraepithelial lesion (HSIL) may be present in your cervix.
  • A test called a colposcopy is recommended for women with ASC-H.

The anatomy of the cervix

The cervix is part of the female genital tract. It is found at the bottom of the uterus where it forms an opening into the endometrial cavity. The narrow passage that runs through the cervix from the vagina to the endometrium is called the endocervical canal.

The part of the cervix inside the vagina is called the exocervix. It is covered by special cells called squamous cells. These cells form a barrier called the epithelium that protect the cervix. The endocervical canal is covered by different kinds of cells that connect to form endocervical glands. The area of the cervix where the exocervix meets the endocervical canal is called the transformation zone. Most cancers of the cervix start in the transformation zone.

The cervix

What is the Pap test and why is it performed?

The Pap test is a screening test designed to look for pre-cancerous and cancerous cells in the cervix. Read our introduction article to learn more about the Pap test.

What does atypical squamous cells, cannot rule out HSIL mean?

Atypical squamous cells, cannot exclude HSIL (ASC-H) means that your pathologist saw abnormal looking squamous cells in your Pap test. It is a preliminary result and not a final diagnosis.

These abnormal cells seen in ASC-H raise the possibility that a more serious pre-cancerous disease called high grade squamous intraepithelial lesion (HSIL) may be present in your cervix. However, ASC-H is not a final diagnosis because some non-cancerous conditions can show similar changes. These conditions include atrophy of the squamous cells in postmenopausal women, metaplastic squamous cells, and inflammation. Normal endometrial cells can also be mistaken for abnormal looking squamous cells.

Why is this important? The cells in ASC-H are not cancer cells but they may be part of a pre-cancerous condition called HSIL. Further testing is recommended.

What causes ASC-H?

Causes of ASC-S include human papillomavirus (HPV) infection, inflammation of the cervix, postmenopausal status, prior radiation therapy, and inadvertent sampling of endometrial cells.

What does ASC-H look like under the microscope?

The cells in ASC-H are called atypical because when examined under the microscope they have an abnormal shape and size compared to normal, healthy squamous cells. In particular, the part of the cell that holds the genetic material, the nucleus, is larger than normal while the body of the cell is smaller. The atypical cells are also usually darker than normal cells. Pathologists call these cells hyperchromatic. The abnormal cells may be found in small groups or as individual cells.

What happens after an ASC-H result on Pap test?

After an ASC-H result your doctor should refer you to a specialist who will perform a colposcopy. A colposcopy allows your doctor to see the entire outer surface of the cervix. ​

During the colposcopy, the doctor will look for any abnormal areas on the surface of your cervix. If an abnormality is found, the doctor may remove a small tissue sample in a procedure called a biopsy. Your doctor may also take a small sample of tissue from the endocervical canal and endometrium. ​

If the tissue removed at the time of the colposcopy finds a precancerous condition such as HSIL your doctor will talk with you about options to remove the disease.

There are several treatment options available: ​

  • Laser ablation– A laser is used to remove the abnormal squamous cells on the surface of the cervix.
  • Loop electrosurgical excision procedure (LEEP)– A special type of knife is used to remove the tissue from the surface of the cervix.
  • Large loop excision of the transformation zone (LLETZ)– Similar to LEEP (above).
  • Cold knife cone biopsy– Similar to LEEP (above).
  • Hysterectomy – In this procedure the entire uterus and cervix is removed. This procedure is usually only performed when squamous cell carcinoma is found and for large tumours. ​

There are many factors to consider when deciding which treatment option is best for you. Talk to your doctor about the options available.

Other helpful resources:

Choosing Wisely Canada

Cancer Care Ontario

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