Cervical Carcinoma

[theTruth_97]

so I know that there are two types of epithelial within the cervix that are divided by the transformation zone. One of them is stratified squamous and the other is simple columnar.

So from my understanding the squamous cell region can lead to squamous cell carcinoma while the simple columnar region can lead to adenocarcinoma. (please correct me if i'm wrong)

Does this mean that both cancer can technically occur simultaneously in a patient? or is it that one of them occurs and then takes over the entire cervical epithelium?

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[seminoma]

so I know that there are two types of epithelial within the cervix that are divided by the transformation zone. One of them is stratified squamous and the other is simple columnar.

So from my understanding the squamous cell region can lead to squamous cell carcinoma while the simple columnar region can lead to adenocarcinoma. (please correct me if i'm wrong)

Does this mean that both cancer can technically occur simultaneously in a patient? or is it that one of them occurs and then takes over the entire cervical epithelium?

Most commonly it occurs in squamous metaplasia area. Majority is SCC (80-85%) and the rest are adeno, adenosquamous, or neuroendocrine. I'm sure it can happen simultaneously, but I doubt it matters.

 

[megaman123]

Majority of squamous dysplasia occurs in the transition zone. This doesn't take away from the fact that you are correct that squamous cell carcinoma arrises from squamous cells and adenocarcinoma arrises from columnar cells. There is no metaplasia involved. They occur separately due to different etiologies.

 

[Transposony]

There is no metaplasia involved.

Are you sure?

 

[megaman123]

HPV is the number one cause of cervical cancer. They infect the keritonocytes of squamous cell epithelium --> causing squamous cell carcinoma. There is no change in epithelium (metaplasia).

 

[Transposony]

HPV is the number one cause of cervical cancer. They infect the keritonocytes of squamous cell epithelium --> causing squamous cell carcinoma. There is no change in epithelium (metaplasia).

Maybe I am splitting hair but this is what Robbin's says:

HPVs infect immature basal cells of the squamous epithelium in areas of epithelial breaks, or immature metaplastic squamous cells present at the squamocolumnar junction (Fig. 22–16). HPVs cannot infect the mature superficial squamous cells that cover the ectocervix, vagina, or vulva. Establishing HPV infection in these sites requires damage to the surface epithelium, which gives the virus access to the immature cells in the basal layer of the epithelium. The cervix, with its relatively large areas of immature squamous metaplastic epithelium, is particularly vulnerable to HPV infection as compared, for example, with vulvar skin and mucosa that are covered by mature squamous cells. This difference in epithelial susceptibility to HPV infection accounts for the marked difference in incidence of HPV-related cancers arising in different sites, and explains the high frequency of cervical cancer in women or anal cancer in homosexual men and a relatively low frequency of vulvar and penile cancer.
Although the virus can infect only the immature squamous cells, replication of HPV occurs in the maturing squamous cells and results in a cytopathic effect, “koilocytic atypia,” consisting of nuclear atypia and a cytoplasmic perinuclear halo. To replicate, HPV has to induce DNA synthesis in the host cells. Since HPV replicates in maturing, nonproliferating squamous cells, it must reactivate the mitotic cycle in such cells.

 

[syoung]

https://en.wikipedia.org/wiki/Metaplasia#Significance_in_disease

though to be honest, not sure if this helps the conversation

 

[Transposony]

https://en.wikipedia.org/wiki/Metaplasia#Significance_in_disease

though to be honest, not sure if this helps the conversation

Doesn't explain why "Normal physiological metaplasia - such as that of the endocervix is highly desirable."
I think the take home point here is that HPV requires cervical metaplasia to infect but it doesn't cause cervical metaplasia.
Instead it causes cervical dysplasia.

 

[seminoma]

The transition zone includes squamous epithelium that was at one point columnar epithelium. Hence squamous metaplasia. This is a developmental concept. The transition zone moves around at different points in the females lifetime.. Mainly at puberty and then after adolescence.

 

[theTruth_97]

thanks all! this was a pretty good discussion