NBME 24 Normal ciliated columnar epithelium replaced by normal squamous epithelium (NBME Answers)

Retired NBME 24 Answers

nbme24/Block 2/Question#50 (reveal difficulty score)
An obese 57-year-old man comes to the ...
Normal ciliated columnar epithelium replaced by normal squamous epithelium 🔍 / 📺 / 🌳 / 📖
tags:

+4 upvote downvote
submitted by ∗lsmarshall(465)

get full access to all content ⋅ pick a username

Metaplasia - A reversible adaptive response in which there is "Reprogramming of stem cellsreplacement of one cell type by another that can adapt to a new stress." Both are normal cells. Respiratory tree should not have squamous cells until respiratory bronchioles (before that; cuboidal in term. bron. > columnar in bronch. > pseudostratified columnar in large. bronch.).

get full access to all content ⋅ pick a username

shayan if its a metaplasia, then how it be normal ? I mean Metaplasia is not normal? +3

artist90 i got it confused bc the question stated that there was a mass in one lobe of lung and i didn't knew that squamous metaplasia also presents as a mass in lung. i missed that on biopsy they were clearly stating squamous metaplasia. +4

suckitnbme @shayan The term "normal" in the answer is used to indicate that the cells appear normal (meaning appropriate size/architecture/appearance). Remember that metaplasia is a normal response to stress. +11

jurrutia Metaplasia is not normal (in the sense that you only have metaplasia as a reaction to stress, but under not under normal circumstances), but the cells in metaplasia are normal. When they become abnormal, you get dysplasia. +

+4 upvote downvote
submitted by ∗medguru2295(64)

get full access to all content ⋅ pick a username

they said "metaplasia"

Metaplasia= normal tissue but in an abnormal place classic example- Barrett's its NORMAL mucousa for the stomach, but in the esophagus.

get full access to all content ⋅ pick a username

+1 upvote downvote
submitted by ∗thisshouldbefree(51)

get full access to all content ⋅ pick a username

metaplasia - (as i learned its definition to be) - defined as replacement of one mature/normal epithelium with another mature/epithelium that is better well suited to handle stress.

get full access to all content ⋅ pick a username

thisshouldbefree also dont forget metaplasia and even dysplasia are still reversible +1

-3 upvote downvote
submitted by ∗krewfoo99(115)

get full access to all content ⋅ pick a username

This could easily be confused with Squamous Cell Carcinoma as they are describing a mass. But i think the key difference is that they mention METAPLASIA. If it was dysplasia, then it would have been cancer.

get full access to all content ⋅ pick a username

usmlecrasherss metaplasia also can lead to cancer FA p206 2019 +

suckitnbme Dysplasia is not cancer since it is, in theory, still reversible. Only when it becomes irreversible is it a carcinoma. +2

Must-See Comments from nbme24

seagull on Intestinal mucosa
tissue creep on Ask the roommate not to smoke in the apartment
drdoom on Adenosine
seagull on Increased serum testosterone concentration
atstillisafraud on Lamins
niboonsh on Only cookies are independently associated ...
atstillisafraud on Scar formation
lamhtu on Decreased adherence
drachenx on Damage to the rectovaginal septum
drdoom on Intestinal mucosa
azibird on Coronavirus
lsmarshall on Organic acid metabolism disorder
sympathetikey on Inhalant abuse
tea-cats-biscuits on Eosinophils