Part 4 GI Flashcards
What is the typical sequence for CRC?
First hit (APC or MMR mutation) –> second hit (KRAS or APC mutation) –> loss of tumor suppressor
Where does a obstructive annular lesion usually occur?
Left side
Where does microsatellite instability (MSI) usually occur?
Right side
What is the clinical presentation of left sided CRC?
Cramping
Change in bowel habits
Occult bleeding
What is the clinical presentation of right sided CRC?
Iron deficiency anemia (fatigue and weakness) d/t occult bleeding
What are some ways to reduce the likely hood of developing CRC?
Screening
COX inhibitors (COX2)
MMR testing
KRAS testing
What medications are not effective in patients with activating K-RAS mutations? (Cormier)
Cetuximab
Panitumumab
What is the most common location of small bowel adenocarcinomas?
Duodenum (Ampulla of Vater)
What are the risk factors for developing small bowel adenocarcinoma?
FAP
Crohn’s Disease (dysplasia in the ileum)
Celiac disease
What is the general presentation of GI tract neuroendocrine tumors?
Crampy abdominal pain, nausea, vomiting, and weight loss
What is the usual presentation of a neuroendocrine tumor in the ileum/jejunum?
Carcinoid syndrome (the serotonin process) Asymptomatic...obstructive metastatic disease
What is the usual presentation of a neuroendocrine tumor in the colon (rare)?
Bulky, right-sided high grade carcinoma
Morphology similar to small cell carcinoma of the lung
What is the usual presentation of a neuroendocrine tumor in the rectum?
Polyps (<1cm)
Favorable prognosis
What is the usual presentation of a neuroendocrine tumor in the appendix?
Asymptomatic
Incidental finding
What is melanosis coli?
Associated with use of anthraceneline laxatives
Causes a brown mucosa
What are some features of lymphomatosis polyposis?
Usually small bowel
Usually B-cell
Appendicitis?
Don’t over think it
When is an appendiceal carcinoma usually benign? Malignant?
Benign if 2cm
What is pseudomyxoma peritonei?
Term for presence of abundant mutinous material on the peritoneal surfaces
What is condyloma accuminatum? What is it associated with?
Polypoid wart
HPV
What is Anal Intraepithelial Neoplasia (AIN)?
Premalignant squamous dysplasia of the anal canal
What is AIN associated with? What does it indicate in an HIV patient?
HPV
Invasive cancer
What is the most common type of anal carcinoma?
Squamous cell carcinoma
What is an important risk factor for developing anal carcinoma?
HPV (type 16)
