Colorectal Surgery Practice Questions

Q: True about melanoma of the anal canal?

Usually presents as anal bleeding. **Explanation:** Anorectal melanoma is a rare but highly aggressive malignancy, accounting for less than 1% of all anorectal cancers. Despite its rarity, it is the third most common site for melanoma after the skin and eyes. **1. Why Option A is Correct:** The most common presenting symptom of anal melanoma is **rectal bleeding** (seen in up to 80% of cases). Patients often present with a mass, pain, or tenesmus. Because it frequently presents as a dark, protruding mass, it is often misdiagnosed as prolapsed internal hemorrhoids, leading to delays in treatment. **2. Why Other Options are Incorrect:** * **Option B:** Historically, Abdominoperineal Resection (APR) was preferred, but current evidence shows that **Wide Local Excision (WLE)** provides similar survival rates with significantly less morbidity. APR is now reserved only for bulky tumors where WLE cannot achieve clear margins or for palliative salvage. * **Option C:** While recurrence is common, it is typically **systemic (distant metastasis)** rather than isolated local recurrence. Most patients die from distant spread (liver, lungs, bone) regardless of the type of local surgical control. * **Option D:** Melanoma is notoriously **radioresistant**. While radiotherapy may be used for palliation or local control in specific cases, it is not a primary curative modality. **High-Yield Clinical Pearls for NEET-PG:** * **Amelanotic variant:** Up to 30–70% of anal melanomas are non-pigmented (amelanotic), making histological diagnosis via S-100, HMB-45, or Mart-1 stains essential. * **Prognosis:** Extremely poor, with a 5-year survival rate of less than 10–15%. * **Spread:** Early lymphatic spread to inguinal and mesenteric nodes and early hematogenous spread are characteristic.

Q: Which of the following are characteristic features of right-sided colon carcinoma?

Anemia and Melena. **Explanation:** The clinical presentation of colorectal carcinoma varies significantly based on the anatomical location of the tumor due to differences in luminal diameter and fecal consistency. **1. Why "Anemia and Melena" is correct:** The right colon (caecum and ascending colon) has a **large luminal diameter** and contains **liquid stool**. Consequently, tumors here tend to grow into large, exophytic, fungating masses without causing early obstruction. These masses are prone to chronic, occult mucosal bleeding. Over time, this leads to **iron-deficiency anemia** (presenting as fatigue or palpitations) and **melena** (dark, tarry stools). In NEET-PG, a common clinical vignette describes an elderly patient with unexplained microcytic hypochromic anemia—this is right-sided colon cancer until proven otherwise. **2. Why other options are incorrect:** * **Obstruction (Option A):** This is characteristic of **left-sided** (sigmoid) lesions. The left colon has a narrower lumen and contains solid, formed stool. Tumors here are often "napkin-ring" or annular, leading to early intestinal obstruction. * **Altered bowel habit (Option B):** This is the classic presentation of **left-sided** or rectal cancer. Because the stool is solid, any luminal narrowing results in constipation, diarrhea, or "pencil-thin" stools. * **Option D:** While melena occurs, "altered bowel habits" is not a primary feature of right-sided lesions, making Option C the more specific "characteristic" choice. **High-Yield Clinical Pearls:** * **Right-sided:** Exophytic mass, Anemia, Melena, Weight loss. * **Left-sided:** Annular growth, Obstruction, Altered bowel habits, Hematochezia (bright red blood). * **Gold Standard Investigation:** Colonoscopy with biopsy. * **Tumor Marker:** CEA (primarily used for monitoring recurrence, not screening).

Q: Venous spread in carcinoma of the rectum most commonly reaches which of the following structures?

Liver. **Explanation:** The correct answer is **Liver (Option C)**. **1. Why Liver is Correct:** The venous drainage of the rectum is primarily mediated by the **Superior Rectal Vein**, which is a direct tributary of the **Inferior Mesenteric Vein (IMV)**. The IMV drains into the **Portal Venous System**. Consequently, malignant cells that enter the bloodstream from a rectal tumor are carried via the portal circulation directly to the liver, making it the most common site for distant hematogenous metastasis in colorectal cancers. *Note:* While the middle and inferior rectal veins drain into the systemic circulation (Internal Iliac Veins), the superior rectal vein's contribution to the portal system is the dominant pathway for early venous spread. **2. Why Other Options are Incorrect:** * **Spleen (Option A):** While the splenic vein is part of the portal system, blood flows *from* the spleen to the liver. Retrograde spread to the spleen is extremely rare. * **Kidney (Option B):** Renal involvement usually occurs via direct local invasion or late-stage systemic spread, not via the primary venous drainage route of the rectum. * **Duodenum (Option D):** The duodenum is an upper gastrointestinal structure. There is no direct venous or lymphatic pathway connecting the rectum to the duodenum. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common site of distant metastasis:** Liver (via Portal system). * **Second most common site of distant metastasis:** Lungs (via Systemic circulation/Internal Iliac veins). * **Lymphatic Spread:** This is the most common overall mode of spread for rectal cancer. It follows the arterial supply (Superior Rectal Artery to Pre-aortic nodes). * **Batten’s Plexus:** This valveless vertebral venous plexus explains how rectal cancer can occasionally metastasize to the **lumbar vertebrae** without involving the liver or lungs.

Q: On colonoscopy, which of the following findings is associated with the highest malignancy potential?

Hundreds of multiple flat polyps. **Explanation:** The malignant potential of a colonic polyp is determined by three main factors: **histology** (villous > tubular), **size** (>2 cm), and **morphology/quantity**. **Why Option B is Correct:** The presence of **hundreds of polyps** is the hallmark of **Familial Adenomatous Polyposis (FAP)**, an autosomal dominant condition caused by a mutation in the *APC* gene. In FAP, the risk of developing colorectal cancer is virtually **100%** by age 40 if a prophylactic colectomy is not performed. Furthermore, **flat (sessile) polyps** carry a higher risk of malignancy compared to pedunculated ones because they are harder to detect, more likely to contain advanced histology (like serrated or villous features), and have a direct pathway for invasion into the submucosa due to the lack of a stalk. **Analysis of Incorrect Options:** * **A & C (Pedunculated Polyps):** These polyps have a fibrovascular stalk. The stalk acts as a "buffer" zone; even if the head of the polyp contains carcinoma, it is considered early-stage if it hasn't invaded the stalk. They are generally easier to resect and have lower risk than flat lesions. * **D (Solitary Flat Polyp):** While a flat morphology is concerning, a single polyp (unless very large) has a significantly lower cumulative risk of transformation compared to the "hundreds" seen in polyposis syndromes. **High-Yield Clinical Pearls for NEET-PG:** * **FAP:** Requires >100 polyps for diagnosis. Most common extra-colonic manifestation: **Duodenal adenomas**. * **Gardner Syndrome:** FAP + Osteomas + Soft tissue tumors (Desmoid tumors). * **Turcot Syndrome:** FAP/HNPCC + CNS tumors (Medulloblastoma/Glioblastoma). * **Villous Adenomas:** Have the highest risk of malignancy among histological types ("Villous is Villainous").

Q: All of the following are true about Familial adenomatous polyposis EXCEPT:

Lifetime risk of colorectal cancer is 70-80%. **Explanation:** Familial Adenomatous Polyposis (FAP) is an autosomal dominant syndrome characterized by the development of hundreds to thousands of adenomatous polyps throughout the colon and rectum. **Why Option C is the correct answer (The Exception):** The lifetime risk of developing colorectal cancer (CRC) in untreated FAP patients is **virtually 100%**, not 70-80%. Malignancy typically develops by age 40-50. Because of this inevitable progression, prophylactic total proctocolectomy is the standard of care, usually performed in the late teens or early twenties. **Analysis of other options:** * **Option A:** By definition, FAP requires the presence of **>100 synchronous colorectal adenomas**. If there are 10–100 polyps, it is termed "Attenuated FAP." * **Option B:** FAP is associated with several **extraintestinal manifestations**, including desmoid tumors (a leading cause of death post-colectomy), osteomas (Gardner syndrome), congenital hypertrophy of retinal pigment epithelium (CHRPE), and dental abnormalities. * **Option D:** The condition is caused by a germline mutation in the **APC gene** located on **chromosome 5q21**. This gene is a tumor suppressor that regulates the Wnt signaling pathway. **High-Yield Clinical Pearls for NEET-PG:** * **Most common extra-colonic malignancy:** Duodenal carcinoma (specifically periampullary). * **Gardner Syndrome:** FAP + Osteomas + Soft tissue tumors (sebaceous cysts, desmoids). * **Turcot Syndrome:** FAP + CNS tumors (Medulloblastoma). * **Screening:** Starts at age 10–12 years with annual flexible sigmoidoscopy. * **CHRPE:** The earliest clinical sign of FAP, detectable at birth via ophthalmoscopy.

Q: All of the following are complications of regional enteritis (Crohn's disease) except?

Intussusception. **Explanation:** The correct answer is **Intussusception**. **1. Why Intussusception is the correct answer:** Crohn’s disease is characterized by **transmural inflammation**, which leads to significant thickening and fibrosis of the bowel wall (the "lead pipe" appearance). This makes the affected segments rigid and non-pliable. Intussusception requires a flexible segment of bowel to invaginate into an adjacent segment; the stiff, thickened wall in Crohn’s disease acts as a physical deterrent to this process. Therefore, intussusception is an extremely rare, if not non-existent, complication of regional enteritis. **2. Why the other options are incorrect:** * **Obstruction (Option A):** This is the **most common** surgical complication of Crohn’s disease. It occurs due to acute inflammation/edema or, more commonly, chronic fibrotic strictures. * **Fistula formation (Option B):** Transmural inflammation leads to deep ulcerations (fissures) that penetrate the serosa, resulting in communications between the bowel and other organs (entero-enteric, entero-vesical, entero-vaginal) or the skin (entero-cutaneous). * **Perforation (Option C):** While less common than in Ulcerative Colitis (due to the protective effect of fibrosis and adhesions), free perforation can occur during acute exacerbations or proximal to a high-grade obstruction. **Clinical Pearls for NEET-PG:** * **Most common site:** Terminal ileum (Ileocolic). * **Pathognomonic feature:** Non-caseating granulomas (seen in 50-70% of cases). * **Endoscopic hallmark:** "Cobblestone appearance" and "Skip lesions." * **Radiological signs:** "String sign of Kantor" (due to terminal ileum stricture) and "Proud flesh" (increased inter-loop distance). * **Surgery:** Not curative; indicated only for complications. The principle is **minimal resection** or **stricturoplasty** to prevent Short Bowel Syndrome.

Question 1

In which type of cancer is immunoguided surgery typically performed?

Accepted Answer

Colon cancer

Answer

Pancreatic cancer

Answer

Jejunal cancer

Answer

Anal canal cancer

Question 2

All are endoscopic modalities of treatment of chronic radiation proctitis, EXCEPT:

Accepted Answer

Ligation therapy

Answer

Bipolar electrocoagulation

Answer

Laser therapy

Answer

Argon plasma coagulation

Question 3

True about melanoma of the anal canal?

Accepted Answer

Usually presents as anal bleeding

Answer

Abdominoperineal resection gives better results than local excision

Answer

Local recurrence at the same site after resection

Answer

Is radiosensitive

Question 4

Which of the following are characteristic features of right-sided colon carcinoma?

Accepted Answer

Anemia and Melena

Answer

Obstruction

Answer

Altered bowel habit

Answer

Altered bowel habit, Anemia, and Melena

Question 5

Venous spread in carcinoma of the rectum most commonly reaches which of the following structures?

Accepted Answer

Liver

Answer

Spleen

Answer

Kidney

Answer

Duodenum

Question 6

A 74-year-old woman presents with a 10-year history of intermittent lower abdominal pain, characterized by colicky nature and a feeling of distension in the left iliac fossa. The pain is relieved by passing flatus or feces. She experiences constipation and passes small pieces of feces. On examination, a vague mass was felt in the left iliac fossa, with no guarding or rebound tenderness, and normal bowel sounds. Investigations included a barium enema and intestinal biopsy. Colonoscopy ruled out colonic neoplasm. Which of the following procedures can be used in this condition?

Accepted Answer

All of the above

Answer

Hamann's procedure

Answer

Washout with proximal diversion

Answer

Percutaneous drainage followed by colonic resection

Question 7

What is the most common cause of an anorectal abscess?

Accepted Answer

Inflammation of an anal gland

Answer

Folliculitis

Answer

Inflammation of the rectal mucosa

Answer

Fissure

Question 8

On colonoscopy, which of the following findings is associated with the highest malignancy potential?

Accepted Answer

Hundreds of multiple flat polyps

Answer

A single pedunculated polyp

Answer

Multiple pedunculated polyps

Answer

A solitary flat polyp

Question 9

All of the following are true about Familial adenomatous polyposis EXCEPT:

Accepted Answer

Lifetime risk of colorectal cancer is 70-80%

Answer

More than 100 colorectal adenomas

Answer

Multiple extraintestinal manifestations

Answer

Mutations in the adenomatous polyposis coli (APC) gene

Question 10

All of the following are complications of regional enteritis (Crohn's disease) except?

Accepted Answer

Intussusception

Answer

Obstruction

Answer

Fistula formation

Answer

Perforation

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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