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MCQs Carcinoid tumors

A 45 year old man is examined for a yearly executive physical. A small mass is palpated in the rectum, and sigmoidoscopy demonstrates it to be a 2-cm mass covered by normal rectal mucosa. Biopsy suggests carcinoid. Which of the following is true regarding rectal carcinoid tumors
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a. Endoscopic resection is sufficient for tumors smaller than 2cm
b. Patients frequently present with the carcinoid syndrome
c. They are rapidly growing tumors
d. Local recurrence is rare with complete resection of the primary lesion
e. Patients can develop the carcinoid syndrome even in the absence of kiver metastaes

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The answer is d. (Brunicardi, pp1094-1095).
– Rectal carcinoids are slowly growing tumors, but they can be locally invasive and metastasize in up to 15% of patients.
– Patients manifest systemic signs of the carcinoid syndrome only in the rare circumstance where hepatitic metastases have occurred.
– The malignant potential is low in carcinoid tumors when they are less than 2cm in diameter, as is typically the case when diagnosed.
– The tumors are curable by wide local transanal resection that includes the muscle layer.
– Endoscopic treatment leave tumor cells near the margin of resection and is felt to increase the risk of recurrence.
– Whether more aggressive resection (abdominoperineal or low anterior resection) improves the prognosis in a larger tumor remain controversial.
– The prognosis is excellent fo rpatients with local disease.

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A 32 year old woman presents to the hospital with a 24h history of abdominal pain of the right lower quadrant. She undergoes an uncomplicated appendectomy for acute appendicitis and is discharged home on the fourth postoperative day. The pathologist notes the presence of a carcinioid tumor (1.2cm) in the tip of the appendix. Which of the following statements is true?

a. The patient should be advised to undergo ileocolectomy
b. The most common location of carcinoids is in the appendix
c. The carcinoid syndrome occurs in more than half of patients with carcioid tumors
d. The tumor is an apudoma
e. Carcinoid syndrome is seen only when the tumor is drained by the portal venous system

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The anwer is d. (Brunicardi, p1134)
– Carcinoid tumors arise from the neuroectoderm and are a type of apudoma.
The most common site of carcinoid tumors is the small bowel, although appendiceal carcinoids are also common. [ERROR, SEE BELOW]
– Carcinoid syndrome, which is characterized by flushing, diarrhea, and cardiac valvular diseae, occurs in a small percentage of patients with carcinoid tutmors; it is rarely seen with appendiceal carcinoids.
– It occurs when serotonin is released into the systemic circulation and thus avoids breakdown by the liver.
– The appropriate therapy for a small carcinoid (less than 2cm) of the appendix is simple appendectomy.
– [CORRECTION! THIS ANSWER STATES THAT THE  SMALL BOWEL IS THE MOST COMMON SITE FOR CARCINOID TUMOR. ACCORDING TO EMEDICINE AND THE ABISTE REVIEW, THE MOST COMMON SITE FOR CARCINOID TUMOR IS THE APPENDIX!!]

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During an appendectomy for acute appendicitis, a 4-cm mass is found in the midportion of the appendix. Frozen section reveals this lesion to be a carcinoid tumor . Which of the following statements is true?

a. No further surgery is indicated
b. A right hemicolectomy should be performed
c. There is about a 50% chance that this patient will develop the carcinoid syndrome
d. Carcinoid tumors arise from islet cells
e. Carcinoid syndrome can occur only in the presence of liver metastases

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The answer is b. (Bruniardi, p1134)
– Carcinoid tumors arise from enterochromaffin cells in the crypts of Lieberkuhn.
– When they are encountered in the appendix and are less than 2cm in size, simple appendectomy is the procedure of choice.
– When the tumors are larger than 2cm, a right hemicolectomy should be performed.
– Carcinoid syndrome (hepatomegaly, diarrhea, cutaneous flushing, right heart valvular disease, and asthma) usually occurs in the presence of liver metastases but can also be seen when there are metastases to sites drained by systemic (as opposed to portal) veins or from primary carcinoids outside the portal system.
– Carcinoid syndrome is rare in patients with carcinoid of the appendix because the tumors are usually discovered before metastases occur.

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Carcinoid: What cells produce serotonin?
What cells are involved in carcinoid tumors?
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ANSWER:
– Serotonin is produced by Kulchitsky cells (enterochromaffin cell or argentaffin cell)
– Carcinoid tumors are derived from enterochromaffin (argentaffin) cells or Kulchitsky cells found in the crypts of Liberkuhn.

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 What does APUD stand for and what is serotonin’s involvement with it? [ABSITE, P.218]

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ANSWER:
– Part of amine precursor uptake decarboxylase system (APUD)

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SOURCES

    

ABSITE KILLER Q&A

STUDY SCHEDULE FOR FUTURE QUESTIONS

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