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Questions and Answers
What dietary factors are associated with an increased risk of colorectal cancer?
What dietary factors are associated with an increased risk of colorectal cancer?
Which genetic syndrome is associated with a higher risk of colon cancer without pre-existing adenomas?
Which genetic syndrome is associated with a higher risk of colon cancer without pre-existing adenomas?
What is typically true about tumors located in the distal colon?
What is typically true about tumors located in the distal colon?
What is a common result of iron deficiency anemia in adults, particularly males?
What is a common result of iron deficiency anemia in adults, particularly males?
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What is the primary genetic alteration seen in familial adenomatous polyposis leading to colorectal cancer?
What is the primary genetic alteration seen in familial adenomatous polyposis leading to colorectal cancer?
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Which immunohistochemical markers are primarily associated with carcinoid tumors?
Which immunohistochemical markers are primarily associated with carcinoid tumors?
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What syndrome may occur due to the release of serotonin by carcinoid tumors?
What syndrome may occur due to the release of serotonin by carcinoid tumors?
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What do carcinoid tumors typically form in their histological appearance?
What do carcinoid tumors typically form in their histological appearance?
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Which of the following are clinical features of carcinoid syndrome?
Which of the following are clinical features of carcinoid syndrome?
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What is the primary origin of gastrointestinal stromal tumors (GISTs)?
What is the primary origin of gastrointestinal stromal tumors (GISTs)?
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What is a common symptom of colorectal cancer that specifically indicates left-sided carcinoma?
What is a common symptom of colorectal cancer that specifically indicates left-sided carcinoma?
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Which diagnostic method is least sensitive and specific for colorectal cancer?
Which diagnostic method is least sensitive and specific for colorectal cancer?
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What factor is NOT considered part of the TNM staging system for colorectal cancer?
What factor is NOT considered part of the TNM staging system for colorectal cancer?
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What is the main purpose of using carcinoembryonic antigen (CEA) in colorectal cancer management?
What is the main purpose of using carcinoembryonic antigen (CEA) in colorectal cancer management?
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Which monoclonal antibody is used in the treatment of metastatic colon cancer by blocking blood vessel growth?
Which monoclonal antibody is used in the treatment of metastatic colon cancer by blocking blood vessel growth?
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Which genetic mutation is commonly associated with resistance to anti-EGFR therapy in colorectal cancer?
Which genetic mutation is commonly associated with resistance to anti-EGFR therapy in colorectal cancer?
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What is a characteristic feature of neuroendocrine tumours (carcinoid) in the GI tract?
What is a characteristic feature of neuroendocrine tumours (carcinoid) in the GI tract?
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What histological feature is characteristic of adenocarcinomas in colorectal cancer?
What histological feature is characteristic of adenocarcinomas in colorectal cancer?
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What is the average age of onset for polyps?
What is the average age of onset for polyps?
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What is the primary genetic mutation associated with Gardner's syndrome?
What is the primary genetic mutation associated with Gardner's syndrome?
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What is the relationship between adenomatous polyps and colorectal cancer?
What is the relationship between adenomatous polyps and colorectal cancer?
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Which screening method is recommended for the target population aged 59 to 69 years?
Which screening method is recommended for the target population aged 59 to 69 years?
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Which genetic condition is primarily linked to Turcot's syndrome?
Which genetic condition is primarily linked to Turcot's syndrome?
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What is a common pathological finding associated with increased risk of colon cancer?
What is a common pathological finding associated with increased risk of colon cancer?
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What demographic is most at risk for colon adenocarcinoma?
What demographic is most at risk for colon adenocarcinoma?
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What condition has virtually a 100% risk of carcinoma within 10 to 15 years without intervention?
What condition has virtually a 100% risk of carcinoma within 10 to 15 years without intervention?
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Which type of polyp is characterized by having a higher malignancy risk associated with size and histologic type?
Which type of polyp is characterized by having a higher malignancy risk associated with size and histologic type?
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What characteristic differentiates Peutz-Jeghers polyps from other polyp types?
What characteristic differentiates Peutz-Jeghers polyps from other polyp types?
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What common feature is observed in juvenile polyps?
What common feature is observed in juvenile polyps?
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Which of the following statements about hyperplastic polyps is true?
Which of the following statements about hyperplastic polyps is true?
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What condition is characterized by multiple hamartomatous polyps and increased risk of certain cancers?
What condition is characterized by multiple hamartomatous polyps and increased risk of certain cancers?
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Which type of neoplastic polyp is most likely to be sessile?
Which type of neoplastic polyp is most likely to be sessile?
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Which type of polyp is formed from inflamed regenerative mucosa and associated with inflammatory bowel disease?
Which type of polyp is formed from inflamed regenerative mucosa and associated with inflammatory bowel disease?
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What is a known complication of adenomatous polyps?
What is a known complication of adenomatous polyps?
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Which group of polyps has no malignant potential but may lead to an increased risk of developing cancers in other organs?
Which group of polyps has no malignant potential but may lead to an increased risk of developing cancers in other organs?
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What defines sessile serrated lesions compared to other polyp types?
What defines sessile serrated lesions compared to other polyp types?
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What genetic alteration is primarily involved in the adenoma-carcinoma sequence in colorectal cancer development?
What genetic alteration is primarily involved in the adenoma-carcinoma sequence in colorectal cancer development?
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Which of the following statements about Lynch syndrome is incorrect?
Which of the following statements about Lynch syndrome is incorrect?
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Which type of tumors in the proximal colon is typically associated with occult bleeding?
Which type of tumors in the proximal colon is typically associated with occult bleeding?
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What is a primary characteristic of colorectal carcinoma that typically develops in the left side of the colon?
What is a primary characteristic of colorectal carcinoma that typically develops in the left side of the colon?
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Which of the following conditions is characterized by a reduced number of polyps compared to familial adenomatous polyposis?
Which of the following conditions is characterized by a reduced number of polyps compared to familial adenomatous polyposis?
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What is the primary risk factor for colorectal cancer associated with increased adenomatous lesions?
What is the primary risk factor for colorectal cancer associated with increased adenomatous lesions?
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Which syndrome is characterized by mutations in the APC gene and also involves gliomas?
Which syndrome is characterized by mutations in the APC gene and also involves gliomas?
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In patients with familial adenomatous polyposis who develop cancer, which gene inactivation is most significant?
In patients with familial adenomatous polyposis who develop cancer, which gene inactivation is most significant?
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What is a key characteristic of adenomatous polyps that correlates with cancer risk?
What is a key characteristic of adenomatous polyps that correlates with cancer risk?
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Which technique is primarily used for the detection of adenomatous polyps in the target screening population?
Which technique is primarily used for the detection of adenomatous polyps in the target screening population?
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What is the peak age demographic associated with colon adenocarcinoma incidence?
What is the peak age demographic associated with colon adenocarcinoma incidence?
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What genetic mutation is specifically linked to Gardner's syndrome apart from APC mutations?
What genetic mutation is specifically linked to Gardner's syndrome apart from APC mutations?
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Which of the following statements about colorectal polyps is true?
Which of the following statements about colorectal polyps is true?
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What is the most significant prognostic factor in colorectal cancer staging?
What is the most significant prognostic factor in colorectal cancer staging?
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Which of the following symptoms is most commonly associated with right-sided colorectal carcinoma?
Which of the following symptoms is most commonly associated with right-sided colorectal carcinoma?
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Which of the following immune histochemical markers is NOT used for mismatch repair protein testing?
Which of the following immune histochemical markers is NOT used for mismatch repair protein testing?
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Which type of colorectal cancer typically has a poorer prognosis due to its invasive nature?
Which type of colorectal cancer typically has a poorer prognosis due to its invasive nature?
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What role does carcinoembryonic antigen (CEA) play in the management of colorectal cancer?
What role does carcinoembryonic antigen (CEA) play in the management of colorectal cancer?
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What is a key feature of adenocarcinomas in colorectal cancer?
What is a key feature of adenocarcinomas in colorectal cancer?
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Which type of monoclonal antibody is designed to block the EGFR signaling pathway in metastatic colon cancer?
Which type of monoclonal antibody is designed to block the EGFR signaling pathway in metastatic colon cancer?
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What is the most common site for neuroendocrine tumors (carcinoids) in the gastrointestinal tract?
What is the most common site for neuroendocrine tumors (carcinoids) in the gastrointestinal tract?
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What clinical manifestation is primarily associated with excess serotonin production from carcinoid tumors?
What clinical manifestation is primarily associated with excess serotonin production from carcinoid tumors?
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Which of the following markers is NOT commonly associated with the immunohistochemistry of carcinoid tumors?
Which of the following markers is NOT commonly associated with the immunohistochemistry of carcinoid tumors?
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What histological characteristic is typically seen in gastrointestinal stromal tumors (GISTs)?
What histological characteristic is typically seen in gastrointestinal stromal tumors (GISTs)?
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What is a key clinical feature that suggests the presence of massive liver metastases in patients with carcinoid syndrome?
What is a key clinical feature that suggests the presence of massive liver metastases in patients with carcinoid syndrome?
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What grade classification for carcinoid tumors is based on mitotic count and Ki67 percent?
What grade classification for carcinoid tumors is based on mitotic count and Ki67 percent?
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What type of polyp is characterized by cystically dilated glands in an inflamed stroma?
What type of polyp is characterized by cystically dilated glands in an inflamed stroma?
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Which statement about sessile serrated lesions is accurate?
Which statement about sessile serrated lesions is accurate?
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What distinguishes villous adenomas from other adenomatous polyps?
What distinguishes villous adenomas from other adenomatous polyps?
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Which of the following types of polyps are considered to have no malignant potential?
Which of the following types of polyps are considered to have no malignant potential?
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What is the primary genetic mutation associated with Familial Adenomatous Polyposis (FAP)?
What is the primary genetic mutation associated with Familial Adenomatous Polyposis (FAP)?
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In Peutz-Jeghers syndrome, what additional clinical feature commonly accompanies the hamartomatous polyps?
In Peutz-Jeghers syndrome, what additional clinical feature commonly accompanies the hamartomatous polyps?
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What significant factor correlates with the risk of malignancy in adenomatous polyps?
What significant factor correlates with the risk of malignancy in adenomatous polyps?
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Which type of polyp is typically associated with longstanding inflammatory bowel disease?
Which type of polyp is typically associated with longstanding inflammatory bowel disease?
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What potential risk is associated with patients who have Cowden syndrome?
What potential risk is associated with patients who have Cowden syndrome?
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Study Notes
Tumours of the Large Bowel
- Primary tumours include non-neoplastic polyps, epithelial neoplasms (benign adenomatous and malignant such as adenocarcinoma and carcinoid), mesenchymal neoplasms, and lymphoma.
- Tumours of the large bowel are more prevalent compared to small bowel tumours.
Polyps
- Protrusions from the mucosal epithelium or submucosal connective tissue, classified as non-neoplastic or neoplastic (adenomas).
- Types include pedunculated (stalked) and sessile (flat).
Non-Neoplastic Polyps
- Hyperplastic, hamartomatous (juvenile, Peutz-Jeghers), inflammatory, and lymphoid polyps.
Hyperplastic Polyps
- Common lesions found in over 50% of individuals over 60.
- Recto-sigmoid location; usually asymptomatic and <5 mm in size.
- Composed of non-neoplastic glands; virtually no malignant potential.
Juvenile Polyps
- Occur in children under 5 but can appear in adults, mainly in the rectum.
- Hamartomatous malformations; no malignancy risk.
Peutz-Jeghers Polyps
- Associated with Peutz-Jeghers syndrome, an autosomal dominant disorder.
- Characterized by mucocutaneous pigmentation and increased risk of various cancers but with polyps having no malignant potential.
Hamartomatous Syndromes
- Cowden syndrome: Autosomal dominant disorder with risk for thyroid and breast cancer.
- Cronkhite-Canada syndrome: Characterized by hamartomatous polyps with additional systemic manifestations.
Inflammatory and Lymphoid Polyps
- Inflammatory polyps occur in ulcerative inflammatory bowel disease.
- Lymphoid polyps consist of intramucosal lymphoid tissue.
Adenomatous Polyps
- Common lesions that can progress to carcinoma, classified into tubular, villous, and tubulovillous types.
- Correlation between size, histological type, and risk of malignancy; all adenomatous polyps should be excised.
- Symptomatic manifestations include occult bleeding or obstruction.
Familial Adenomatous Polyposis (FAP)
- Autosomal dominant disorder causing numerous adenomatous polyps, with nearly 100% risk of carcinoma by age 40, necessitating preventive colectomy.
Gardner’s and Turcot’s Syndromes
- Gardner's syndrome: Variation of FAP with additional soft tissue and bone tumors.
- Turcot's syndrome: Variation of FAP associated with brain neoplasms.
Adenoma-Carcinoma Sequence
- Progression from adenomatous lesions to colorectal cancer driven by genetic mutations (APC, K-ras, DCC, p53).
- High prevalence of adenomas correlates with colorectal cancer incidence.
Screening and Diagnosis
- Targeted bowel screening for ages 59-69, typically every two years.
- Diagnosis through colonoscopy, biopsy, and ancillary tests including imaging and cancer markers (CEA).
Colorectal Carcinoma
- Most common in developed countries; typically diagnosed in the 7th decade.
- Symptoms may include changes in bowel habits, rectal bleeding, and abdominal pain.
- Left-sided tumours present more frequently with obstruction due to narrower lumen compared to the right side.
Prognosis
- Determined by stage, grade, genetic factors, and adequacy of surgical excision.
- TNM staging: T (depth), N (regional lymph nodes), M (distant spread).
Neuroendocrine Tumours (Carcinoid)
- Arise from neuroendocrine cells throughout the GI tract, low-grade malignancies with a potential for hormone secretion.
- Symptoms may include bowel obstruction, flushing, diarrhea, and carcinoid syndrome associated with significant liver metastases.
Mesenchymal Tumours
- Include benign types like lipomas and gastrointestinal stromal tumours (GISTs).
- GISTs arise from pacemaker cells (Interstitium of Cajal) and are most commonly found in the stomach and small intestine.
Tumours of the Large Bowel
- Tumours are classified into primary (non-neoplastic polyps, epithelial neoplasms, mesenchymal neoplasms, lymphoma) and rare secondary tumours.
- Large bowel tumours are more prevalent than small bowel tumours.
Polyps
- Polyps are masses that arise from bowel epithelium or submucosa, protruding into the gut lumen.
- Types include non-neoplastic polyps and neoplastic polyps (adenomas).
Non-Neoplastic Polyps
- Hyperplastic polyps: Common, asymptomatic, usually <5 mm.
- Juvenile polyps: Hamartomatous, found in children <5 years, no malignant potential.
- Peutz-Jeghers polyps: Autosomal dominant, associated with mucocutaneous pigmentation and increased cancer risk.
- Inflammatory polyps: Result from inflammatory bowel disease.
- Lymphoid polyps: Composed of intramucosal lymphoid tissue.
Adenomatous Polyps (Neoplastic)
- Prevalence increases with age (50% at age 60).
- Types: Tubular, villous, tubulovillous.
- Can be pedunculated or sessile, with malignancy risk correlating with size and histologic type.
Familial Adenomatous Polyposis (FAP)
- Autosomal dominant; mutations in the APC gene.
- Characterized by numerous adenomatous polyps (≥100), virtually 100% risk of colon carcinoma by age 40.
Gardner’s Syndrome
- A variant of FAP with additional features like epidermoid cysts and increased risk of duodenal and thyroid cancers.
Turcot’s Syndrome
- Another variant of FAP, associated with colorectal polyps and brain tumours.
Adenoma-Carcinoma Sequence
- The process by which adenomatous lesions transform into colorectal cancer, involving specific mutations (APC, K-ras, DCC, p53).
Screening and Diagnosis
- Recommended for aged 59 to 69, occurs biannually using faecal immunochemical tests.
- Colonoscopy serves as the primary diagnostic tool.
Colorectal Carcinoma
- Peak incidence in the 7th decade; often presents asymptomatically until advanced.
- Symptoms include abdominal pain, bleeding, and change in bowel habits.
Risk Factors for Colon Carcinoma
- Increasing age, adenomatous polyps, hereditary syndromes, inflammatory bowel disease, high-fat diet, obesity, and physical inactivity.
Lynch Syndrome (HNPCC)
- Autosomal dominant; predisposes to colorectal and other non-GI cancers.
- Lower number of polyps compared to FAP, primarily right-sided tumours.
Symptoms and Clinical Presentation
- Right-sided lesions may lead to anaemia; left-sided tend to obstruct and cause rectal bleeding.
- Tumour characteristics can include well-differentiated to poorly differentiated histology.
Prognostic Factors
- Staging, tumour grade, location (left-sided worse), and genetic mutations significantly determine patient outcomes.
Ancillary Tests and Treatment
- Include immunohistochemistry, microsatellite instability testing, and gene mutation screenings.
- Monoclonal antibodies (e.g., Erbitux, Avastin) target metastatic colon cancer.
Neuroendocrine Tumours (Carcinoids)
- Arise from neuroendocrine cells with low-grade malignancy, may secrete hormones.
- Clinical manifestations include obstruction and secretion syndromes such as carcinoid syndrome.
Mesenchymal Tumours
- Include benign lipomas and gastrointestinal stromal tumours (GISTs), arising from interstitial cells of Cajal.
Gastrointestinal Stromal Tumours (GISTs)
- Mesenchymal neoplasms primarily in the stomach and small intestine; linked to mutations in receptor tyrosine kinase genes.
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Description
Explore the various types of tumours affecting the large bowel, including primary tumours such as non-neoplastic polyps and various neoplasms. This quiz dives into classifications, characteristics of polyps, and their prevalence compared to small bowel tumours.
