34. Cervical intraepithelial neoplasia CIN III

From greek.doctor
Overview of the slide

Staining: PAS-H . Organ: Cervix

Description: We can see two sections of a cervix. The top one is the best, so we’ll go with that. On the bottom left corner can we see a very PAS-positive area. Upon closer inspection can we see that the PAS positive cells are stratified squamous cells. The other epithelium found in this section isn’t PAS-positive. This epithelial layer is also much thicker than the other.

The PAS-negative epithelium contains pleomorphic cells (they have different shapes and sizes). These cells are larger than the PAS-positive cells as well. We can also see some cells undergoing mitosis here. A special cell type with a white “ring” around an irregular nucleus can be seen.

Diagnosis: Cervical intraepithelial neoplasia CIN III

Note the abrupt change from healthy, PAS-positive to PAS-negative epithelium.

Causes: Human papilloma virus (HPV) infection

Theory: The normal epithelium here is the PAS-positive epithelium. The PAS positivity comes from the large amount of glycogen in the epithelial cells. Because the epithelium is stratified squamous and not columnar we know this section is from the exocervix.

The PAS-negative epithelium has undergone dysplasia. These cells have lost their maturation and orientation, and some undergo mitosis. The loss of maturation and orientation has caused them to not produce glycogen like healthy cells do, which makes them PAS-negative. They are also pleomorphic. They’re larger than normal epithelial cells, and don’t have the same shape as the healthy cells anymore.

The cells with the perinuclear halo and irregular nuclei are called koilocytes, which are a sign of HPV infection. The presence of these cells is called koilocytosis or koilocytic atypia.

Note also that the cells are pleiomorphic.

For the types of cervical intraepithelial neoplasia (CIN), see the theory topic. Because dysplasia is in the whole width of the epithelium in this slide it is classified as CIN III.