colon cancers from pathoma Flashcards

1
Q

What are the pathways by which colorectal carcinomas arise?

A

adenoma-carcinoma sequence (most common) or microsatellite instability pathway

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2
Q

What is the microsatellite instability pathway?

A

microsatellites are repeating sequences of non-coding DNA. everytime we have cell division, we copy the microsatellites are copied too. if the patient has a problem with DNA mismatch repair, they will have microsatellite INSTABILITY. other genes, too, are unstable. mutations in other genes can cause the development of a colorectal carcinoma

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3
Q

HNPCC

A
hereditary nonpolyposis (tumors arise de novo- no adenoma first) colorectal carcinoma.
they have incr. risk of colorectal, ovarian, and endometrial carcinoma.  often arises de novo at an early age, often right sided.
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4
Q

how does left sided cancer usually present?

A

decr. stool caliber, LLQ pain, and blood streaked stool. it is squeezing down on the lumen. adenoma carcinoma sequence very common

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5
Q

how does right sided cancer usually present

A

tends to grow as a raised lesion. may cause iron deficiency anemia (the colon lumen is bigger). key location for HNPCC lesions.

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6
Q

What is the tumor marker for colon cancer?

A

CEA. useful for assessing tx response and detecting recurrence. not good for screening.

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7
Q

key finding on X ray for colorectal cancer

A

apple core lesion

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