pathoma metaplasia/uw concept

[aspiringmd1015]

so UW mentions that the squamous metaplasia in the cervix doesnt increase the risk for cancer, and it just a nomral reponse to acidity, and sattar mentions that one of the only examples of metaplasia with no increased risk of ca is apocrine metaplasia of the breast. So is cervical squamous metaplasia another one?

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[slz1900]

I don't think UW is totally right here. Squamous metaplasia of the transformation zone is physiological and normal, but it can go on to develop into cervical carcinoma, and it would make sense that the more advanced the metaplasia the more likely it is to turn into dysplasia and CIS. I think what they're getting at is metaplasia of the cervix will be found normally in the transformation zone and therefore isn't automatically a precursor to dysplasia and neoplasia. Apocrine metaplasia is distinct because it is a pathological response in fibrocystic change and all other metaplastic changes resulting from abnormal stress increase the risk of cancer, but apocrine does not.

 

[Reperfused]

For sure Squamous Metaplasia of the cervix can progress to carcinoma.

 

[aspiringmd1015]

UW was saying that HPV has no role in that squamous metaplasia though. So maybe its trying to say local irritation and other RF's like smoking are the reason for taht, even though most of the RF's are related to acquiring HPV ie early sex etc

 

[Transposony]

UW was saying that HPV has no role in that squamous metaplasia

QID?

 

[aspiringmd1015]

1041

QID?

 

[slz1900]

UW was saying that HPV has no role in that squamous metaplasia though. So maybe its trying to say local irritation and other RF's like smoking are the reason for taht, even though most of the RF's are related to acquiring HPV ie early sex etc

Uworld is right. The metaplasia is physiological at the transformation zone. There's no local irritation or environemntal exposures involved.

 

[aspiringmd1015]

a champ like pholston or dfib slim could maybe add a point or two here to help. If transposony doesnt know it, its probably not HY enough lol

 

[Transposony]

I wanted to know the context of the UW question/explanation before answering but since I have not yet completed my UW, I cannot access the QID 1041.

However, according to Robbins:

HPVs infect immature basal cells of the squamous epithelium in areas of epithelial breaks, or immature metaplastic squamous cells present at the squamocolumnar junction. HPVs cannot infect the mature superficial squamous cells that cover the ectocervix, vagina, or vulva. Establishment of HPV infection in these sites requires damage to the surface epithelium, which allows the virus access to the immature cells in the basal layer of the epithelium.

^This I didn't know!

By definition metaplasia is replacement of one cell type by another due to exposure to an irritant (which in this case is due to acidity of vagina)
But HPV infects metaplastic cells to cause dysplasia >CIS>Cervical Ca.
So, UW is correct in saying that HPV has no role in squamous metaplasia.

Therefore, metaplasia per se is NOT progressing to Cervical Cancer but HPV infection of the metaplastic cells is causing the cancer.
.