CIN - Cervical intraepithelial neoplasia (cervical dysplasia). CIN I; CIN II; CIN III explained

Cervical Intraepithelial Neoplasia, also known as CIN; or cervical dysplasia.
Cervical Dysplasia is Characterized by abnormal growth of cells on the surface of the cervix. Cervical intraepithelial neoplasia is not cancer, but it has potential to become cervical cancer.
Cervical intraepithelial neoplasia commonly occurs in the transitional area of cervix, where squamous epithelium of the vagina and the columnar epithelium of the endocervix meets.
Cervical intraepithelial neoplasia is classified from CIN 1; to CIN 3. where CIN 1 is mild dysplasia; and CIN 3 is Severe Dysplasia.

There is no specific symptoms for CIN. But nonspecific symptoms include:
• Vaginal bleeding
• Post menopausal bleeding.
• Abnormal discharge from vagina.
• Pelvic pain
• Abnormal appearance or palpation of cervix.
The Cause of cervical dysplasia is human papillomavirus infection. especially HPV type 16 and type 18.
Not all papilovma virus infection causes cervical dysplasia and not all cervical dysplasia will become cancer.
Mechanism oფ the Dysplasia is thought, human papillomavirus can inactivate tumor suppressor genes such as the p53 gene and the RB gene, thus allowing the infected cells to grow unchecked and accumulate successive mutations, eventually leading to cancer.
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Risk Factors for developing CIN:
Infection with a high-risk type of HPV, such as 16, 18, 31, or 33
Immunodeficiency (e.g. HIV infection); Multiple sex partners; Cigarette smoking.
Diagnosis:
Pap smear is used for screening method, which can detect dysplastic cells,
Colposcopy with direct biopsy is the standard for disease detection.
The diagnosis of CIN or cervical carcinoma requires a biopsy for histological analysis.

Most mild dysplasia is called CIN 1 also known as Low-grade squamous intraepithelial lesion (LSIL).
Cin 1 is spread to the basal 1/3 of the epithelium.
CIN 1 has High rate of regression back to normal cells.

CIN 2; – Represents moderate dysplasia confined to the basal 2/3 of the epithelium. CIN 2 sometimes is
High-grade squamous intraepithelial lesion (HSIL) which is more severe form. And high probability to progress into CIN 3.
And CIN 3 ; Severe dysplasia with undifferentiated neoplastic cells that span more than 2/3 of the epithelium.
May also be referred to as cervical carcinoma in situ.

Prevention:
HPV Vaccination is the most important primary prevention of both CIN and cervical cancer.
Vaccine is available for both, male and females. 9-26 years. which is recommended, before sexual debut.
Treatment:
CIN 1 Treatment is not recommended if it lasts less then 2 years. Because high probability to clear on its own within 12 months. Close follow up is important.
Treatment for higher-grade CIN involves removal or destruction of the abnormal cervical cells by cryocautery, electrocautery, laser cautery, loop electrical excision procedure (LEEP), or cervical conization.
Prognosis:
most CIN spontaneously regress. Left untreated, about 70% of CIN 1 will regress within one year; 90% will regress within two years.
About 50% of CIN 2 cases will regress within two years without treatment.
Progression to cervical carcinoma in situ (CIS) occurs in approximately 11% of CIN 1 and 22% of CIN 2 cases.
Progression to cancer typically takes 15 years with a range of 3 to 40 years.
By Haeok Lee1,2*, Mary Sue Makin3, Jasintha T Mtengezo4,5 and Address Malata6 - http://clinmedjournals.org/articles/o..., CC BY 4.0, https://commons.wikimedia.org/w/index...
By Cancer Research UK - Original email from CRUK, CC BY-SA 4.0, https://commons.wikimedia.org/w/index...

By M.H.B. Catroxo and A.M.C.R.P.F. Martins - [1], CC BY 3.0, https://commons.wikimedia.org/w/index...
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