Cervical carcinomas usually originate from precursor lesions in the squamous (cervical intraepithelial neoplasia –CIN- grade 1-3) or glandular epithelium (adenocarcinoma-in-situ (ACIS)). CIN 3 is usually designated as carcinoma in situ, a carcinoma that is limited to the surface epithelium without stromal invasion.
Squamous cell carcinoma is the dominating type (85%) while adenocarcinomas, originating from the glandular epithelium, is less common (about 10%) and 5% constitutes other types.
|Specimen of cervix with polypous tumor. Click to enlarge.
||A photomicrograph of the squamous epithelial carcinoma tumor to the left. Click to enlarge.
Squamous cell carcinoma growth may be polypous or infiltrative. Many malignancy grading systems have been proposed, although a simple division into two types is generally recommended. These are keratinizing and non-keratinizing squamous cell types. .
There are a number of squamous cell carcinoma subtypes, but they are of no prognostic significance.
Microinvasive squamous cell carcinoma is usually seen in areas with extensive carcinoma in situ (CIN 3) with downgrowth in glands, luminal necrosis and keratinization. Several studies indicate that when tumors infiltrate 3 mm or less, there is very low risk for recurrence or tumor metastasis.
Adenocarcinoma (originating in the glandular epithelium) can sometimes be difficult to separate from adenocarcinoma in the uterus. In these instances, immunohistochemical investigation may be helpful.
There are several subtypes of adenocarcinoma :
- Clear cell
- Serous papillary
- Adenosquamous (mixed tumor with both glandular and sqaumous cell)
In addition to the above mentioned carcinoma types, there are a number of uncommon variants such as neuroendocrine (small cell carcinoma) . This is a very aggressive tumor with 5-year survival rate of 14-39%. This tumor is treated differently than the other cervical carcinomas types, and it is therefore important for the pathologist to recognize. Immunohistochemical investigation is often necessary in these cases for correct classification.