What are CIN1 and LSIL?

There are many systems in use for classifying precancerous conditions of the cervix. These two are world-wide used.

The Bestheda System (since 1990)

This classification is recommended by WHO for cytological reports. It was developed in 1990 in the United States National Cancer Institute. It is a system for reporting cervical or vaginal cytologic diagnoses, used for reporting Pap semar results.

  • LSIL (also called low-grade squamous intraepithelial lesion, or mild dysplasia) seen on a Pap test is generally CIN 1.
  • HSIL (also called high-grade squamous intraepithelial lesion, or moderate or severe dysplasia) seen on a Pap test can be CIN 2, CIN2/3, or CIN 3.
  • ASCUS and ASCH classify Atypical cells

The name comes from the location (Bestheda, Maryland) of the conference sponsored by the National Institutes of Health, that stablisehed the system.

The Cervical Intraepithelial Neoplasia (since 1968)

CIN is the term used to describe abnormal cervical cells that were found on the surface of the cervix after a biopsy.

  • CIN 1 changes are mild, or low grade. They usually go away on their own and do not require treatment.
  • CIN 2 changes are moderate and are typically treated by removing the abnormal cells.

However, CIN 2 can sometimes go away on its own. Some women, after consulting with their health care provider, may decide to have a colposcopy with a biopsy every 6 months.
CIN 2 must be treated if it progresses to CIN 3 or does not go away in 1 to 2 years.

  • CIN 3 changes are severely abnormal. Although CIN 3 is not cancer, it may become cancer and spread to nearby normal tissue if not treated. Unless you are pregnant, it should be treated right away.


NLM: Negative for intrapetithelial lesion or malignacy
LISL: Low grade squamous intrapithelial lesion
HSIL: Low grade squamous intrapithelial lesion
ASC-US: atypical squamous cells of undetermined significance
ASC-H: atypical squamous cells suspicious for HSIL
CIN: cervical intraepithelial neoplasia

Smear Appearance

Papanicolaou (PAP) cytological classifications

The Papanicolaou (PAP) cytological classifications are used to interpret Pap smear results, categorizing cervical cells and assessing the presence of potential abnormalities. Here’s the interpretation of the mentioned categories:

PAP II-p (Papanicolaou II-partial):

  • Indicates normal cells but with some non-specific changes that may be caused by infections or other benign factors. It is generally not considered a worrisome result.

PAP III-p (Papanicolaou III-partial):

  • Indicates more noticeable cellular changes but is still not a definitive result of precancerous lesion. It may suggest the presence of abnormal cells, requiring closer follow-up or additional tests.

PAP IIID1 (Papanicolaou IIID1):

  • This classification is often associated with the Bethesda system as “Atypical squamous cells of undetermined significance” (ASC-US). It indicates more pronounced cellular changes than PAP III but is not clear enough to confirm the presence of a precancerous lesion.

PAP IIID2 (Munich III) (Papanicolaou IIID2):

  • Similar to PAP IIID1 but with a higher suspicion of precancerous lesions. The “Munich III” classification is often associated with high-grade cells and may require more intensive follow-up or biopsy for a more accurate assessment.

It’s important to note that these classifications may vary slightly depending on the system used in different countries or medical institutions. Additionally, the interpretation and management of these results should be done by healthcare professionals, such as gynecologists or pathologists, who will consider the clinical context and other factors to determine the appropriate course of action.

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