Colorectal Surgery Practice Questions

Q: Hereditary non-polyposis colorectal cancer (HNPCC) has an increased risk of all the following cancers except?

Pancreas. **Explanation:** Hereditary Non-Polyposis Colorectal Cancer (HNPCC), also known as **Lynch Syndrome**, is an autosomal dominant condition caused by germline mutations in **DNA Mismatch Repair (MMR) genes** (primarily *MLH1, MSH2, MSH6,* and *PMS2*). This leads to microsatellite instability (MSI). While HNPCC is primarily associated with colorectal cancer, it is a multi-organ syndrome. The correct answer is **Pancreas** because, although pancreatic cancer can occur in Lynch Syndrome, its association is significantly weaker compared to the other options. In the context of standard NEET-PG patterns and the **Amsterdam II Criteria**, the "core" extracolonic cancers are more frequently tested. * **Option A (Endometrium):** This is the **most common** extracolonic malignancy in Lynch Syndrome. The lifetime risk is approximately 40-60%, often appearing before the colorectal primary. * **Option B (Ovary):** Ovarian cancer is a well-documented component of Lynch Syndrome, with a lifetime risk of approximately 10-12%. * **Option C (Stomach):** Gastric cancer is the second most common extracolonic GI malignancy in these patients (after the colon), particularly in Asian populations. **High-Yield Clinical Pearls for NEET-PG:** * **Amsterdam II Criteria (3-2-1 Rule):** 3 relatives with Lynch-associated cancer (Colorectum, Endometrium, Small bowel, Ureter/Renal pelvis); 2 generations; 1 diagnosed before age 50. * **Bethesda Criteria:** Used to determine which colorectal tumors should be tested for MSI. * **Tumor Location:** HNPCC tumors are characteristically **right-sided** (proximal to splenic flexure) and occur at a young age (~45 years). * **Other associated sites:** Small bowel, hepatobiliary tract, brain (Turcot Syndrome), and skin (Muir-Torre Syndrome).

Q: Familial adenomatous polyposis is characterized by all of the following except:

Autosomal recessive transmission. **Explanation:** **Familial Adenomatous Polyposis (FAP)** is a hereditary colorectal cancer syndrome caused by a germline mutation in the **APC (Adenomatous Polyposis Coli) gene** located on chromosome **5q21**. 1. **Why Option A is the correct answer:** FAP follows an **Autosomal Dominant** pattern of inheritance, not recessive. A child of an affected parent has a 50% chance of inheriting the mutation. Approximately 25% of cases arise from *de novo* mutations without a family history. 2. **Analysis of other options:** * **Option B:** By definition, classic FAP is characterized by the development of **hundreds to thousands** of adenomatous polyps throughout the colon and rectum, typically appearing in the second decade of life. * **Option C:** FAP is a systemic predisposition to polyps. **Duodenal adenomas** (especially in the periampullary region) occur in up to 90% of patients and are the second leading cause of cancer death in FAP after colorectal cancer. * **Option D:** FAP often presents with **extra-intestinal manifestations**. When associated with osteomas, soft tissue tumors (desmoids), and dental abnormalities, it is known as **Gardner’s Syndrome**. Association with CNS tumors (medulloblastoma) is known as **Turcot’s Syndrome**. **High-Yield Clinical Pearls for NEET-PG:** * **CHRPE:** Congenital Hypertrophy of Retinal Pigment Epithelium is the earliest detectable clinical sign of FAP. * **Management:** Prophylactic **Proctocolectomy** is the treatment of choice, usually performed in late teens or early 20s, as the risk of progression to colorectal carcinoma is **100%** by age 40-50. * **Screening:** Annual flexible sigmoidoscopy starting at age 10-12 for at-risk relatives.

Q: Per rectum examination is not a useful test for the diagnosis of which of the following conditions?

Pilonidal sinus. **Explanation:** The Digital Rectal Examination (DRE) or Per Rectum (PR) examination is a fundamental clinical tool used to evaluate pathologies of the anal canal, rectum, and adjacent structures (like the prostate). **Why Pilonidal Sinus is the Correct Answer:** A **Pilonidal Sinus** is a condition occurring in the **sacrococcygeal region** (the cleft of the buttocks), usually caused by hair follicles penetrating the skin. It is an **extracanalicular** condition located superficial to the sacrum and coccyx. Since the pathology is located on the skin surface of the natal cleft and does not involve the anal canal or rectal lumen, a PR examination provides no diagnostic utility for this condition. Diagnosis is purely clinical via inspection. **Analysis of Incorrect Options:** * **Anal Fissure:** PR examination (though often painful and sometimes deferred for a visual inspection) is used to assess sphincter tone and rule out associated pathologies like sentinel piles or hypertrophied anal papillae. * **Hemorrhoids:** While internal hemorrhoids are soft and often not palpable unless thrombosed, a PR exam is essential to rule out other causes of rectal bleeding (like malignancy) and to assess the anal canal. * **Rectal Ulcer:** Solitary Rectal Ulcer Syndrome (SRUS) or malignant ulcers are directly palpable via PR exam. The clinician can feel the induration, depth, and distance from the anal verge. **Clinical Pearls for NEET-PG:** * **Positioning:** The preferred position for a PR exam is the **Left Lateral (Sims) position**. * **Contraindication:** A PR exam is strictly contraindicated in cases of **suspected Coccygodynia** (due to pain) and should be performed with extreme caution/topical anesthesia in **acute anal fissures**. * **Pilonidal Sinus Fact:** It is most common in young, hairy males ("Jeep Bottom") and the primary treatment is wide local excision or flap reconstruction (e.g., Limberg flap).

Q: A 33-year-old male presents with sudden onset acute abdominal pain, constipation for 1 day, persistent hiccups, and occasional vomiting. An abdominal X-ray was performed. Identify the pathology.

Sigmoid volvulus. ***Sigmoid volvulus*** - The abdominal X-ray demonstrates the classic **"coffee bean" sign**, which is a pathognomonic finding for sigmoid volvulus, representing a massively dilated loop of the sigmoid colon. - The clinical presentation of acute abdominal pain, distension, and constipation is consistent with a **large bowel obstruction**, which is caused by the twisting of the sigmoid colon on its mesentery. *Caecal volvulus* - Radiographically, a caecal volvulus typically appears as a kidney-shaped or comma-shaped dilated loop of bowel displaced towards the **left upper quadrant**, which is not seen in this image. - It is less common than sigmoid volvulus and is often associated with a mobile cecum and the absence of prior abdominal surgery. *Intussusception* - Intussusception, the telescoping of one bowel segment into another, is more common in children and classically presents with a **"target sign"** on ultrasound or CT. - While it can cause obstruction in adults, the radiographic finding of a massive, single, air-filled loop is not characteristic of intussusception. *Mechanical obstruction* - This is a general term for physical blockage of the bowel lumen. While sigmoid volvulus is a specific cause of mechanical obstruction, the X-ray provides specific findings that point to a more precise diagnosis. - Non-specific signs of mechanical obstruction, such as multiple dilated bowel loops with **air-fluid levels**, are different from the characteristic single-loop dilation seen here.

Q: A 70-year-old patient presents with absolute constipation and abdominal distension. The X-ray abdomen is given below. What is the most likely diagnosis?

Sigmoid Volvulus. ***Sigmoid Volvulus*** - The abdominal X-ray demonstrates the classic **"coffee bean" sign**, which is a massively dilated, haustra-less loop of the sigmoid colon that appears bent upon itself, originating from the pelvis. - This diagnosis aligns with the clinical presentation of an elderly patient with **absolute constipation** and significant **abdominal distension**, which are hallmark features of a closed-loop large bowel obstruction caused by sigmoid volvulus. *Caecal Volvulus* - A caecal volvulus typically presents as a **kidney-bean** or **comma-shaped** dilated structure that is displaced from the right lower quadrant towards the left upper quadrant, which is morphologically distinct from the inverted U-shape seen in the image. - The dilated cecum in a caecal volvulus often retains some **haustral markings**, unlike the smooth, featureless appearance of the dilated sigmoid colon seen here. *Intestinal Obstruction* - While sigmoid volvulus is a cause of intestinal obstruction, this is a non-specific diagnosis. The radiological findings are specific enough to identify the underlying cause. - A general diagnosis of intestinal obstruction doesn't account for the pathognomonic **"coffee bean" sign**, which specifically points to sigmoid volvulus as the etiology. *Small Bowel Volvulus* - The dilated loop in the X-ray lacks **valvulae conniventes** (also known as plicae circulares), which are characteristic transverse folds of the small bowel. The loop's appearance is consistent with the large bowel. - The caliber of the distended loop is exceptionally large, which is more typical for a colonic obstruction rather than a small bowel obstruction, which usually involves multiple, smaller-caliber loops.

Q: A patient with grade 2 hemorrhoids underwent surgery, identify the instrument.

Haemorrhoids band kit. ***Haemorrhoids band kit*** - The image shows a **band ligator** applying a small elastic band to the base of an internal hemorrhoid, which is the procedure known as **rubber band ligation**. - This technique is a common office-based procedure for **grade I, II, and selected grade III** internal hemorrhoids, causing them to necrose and slough off by cutting off their blood supply. *Haemorrhoids resection kit* - This kit contains instruments for a formal **hemorrhoidectomy**, a surgical procedure that involves excising the hemorrhoidal tissue, typically reserved for severe **grade III and IV hemorrhoids**. - A resection is a more invasive procedure involving cutting and suturing, which is different from the banding method shown. *Stapler kit* - A stapler kit is used for a **stapled hemorrhoidopexy** (PPH procedure), which involves a circular stapler to resect a ring of mucosa above the hemorrhoids and lift them back into a normal position. - The instrument and the principle of action (resection and fixation) are distinct from the ligation shown in the image. *CO2 laser* - **Laser hemorrhoidoplasty** uses a laser probe to deliver energy to shrink the hemorrhoidal plexus; it does not involve the application of a mechanical band. - The instrument is a thin laser fiber, which looks different from the ligator depicted in the illustration.

Q: A homosexual man complains of painful defecation and mass protruding from the anal canal. Biopsy reveals squamous cell carcinoma of anus. Correct management for this patient is

Combined chemoradiation. ***Combined chemoradiation***- **Combined chemoradiation (Nigro protocol)** is the standard of care and preferred, organ-preserving primary treatment for most stages of squamous cell carcinoma of the anus.- This curative regimen typically involves sequential or concurrent use of **5-Fluorouracil**, **Mitomycin C** (or Cisplatin), and focused external beam radiation therapy, resulting in high rates of complete remission.*Chemotherapy*- Chemotherapy alone is insufficient as a curative primary modality for localized anal carcinoma and is inferior to combined treatment.- Systemic chemotherapy is primarily reserved for the management of **metastatic** disease or palliation in advanced, unresectable cases.*Abdominoperineal repair*- **Abdominoperineal resection (APR)**, which creates a permanent colostomy, is primarily reserved as a highly morbid **salvage operation** for locoregional failure following initial chemoradiation.- Primary APR is rarely performed because combined chemoradiation offers similar long-term survival rates with sphincter preservation.*Wide local excision*- **Wide local excision (WLE)** is only appropriate for very small (T1, <2cm), well-differentiated tumors located at the anal margin (perianal skin), which are much less common.- A bulky, protruding mass usually indicates a deeper primary tumor or involvement of the anal canal, requiring definitive **chemoradiation** rather than surgery.

Q: A man came with complaints of recurrent discharge and pain due to lesions around the anus for 3 years. A diagnosis of fistula-in-ano is made. What is the gold standard investigation for this condition?

MRI. ***MRI*** - **Gold standard investigation** for fistula-in-ano for preoperative assessment - Provides **superior soft tissue contrast** and multiplanar imaging capabilities - Accurately delineates the **fistula tract, internal and external openings** - Detects **secondary tracts, horseshoe extensions, and abscesses** - Helps in **Parks classification** (intersphincteric, trans-sphincteric, suprasphincteric, extrasphincteric) - Essential for **surgical planning** and predicting recurrence risk - MRI with fat suppression sequences (T2-weighted) provides best visualization *Fistulogram* - Outdated investigation with **limited accuracy** (40-50%) - Cannot adequately assess sphincter involvement or secondary tracts - Invasive and uncomfortable for the patient - Risk of extravasation and infection *USG (Endoanal/Transperineal Ultrasound)* - Useful adjunct but **not gold standard** - Operator-dependent with limited field of view - Difficulty visualizing high or complex fistulas - Less accurate for secondary extensions *CECT* - Not routinely used for fistula-in-ano assessment - **Inferior soft tissue resolution** compared to MRI - Radiation exposure - Limited differentiation of sphincter anatomy

Q: A 65-year-old patient undergoes colonoscopy for altered bowel habits. A 6 cm colonic mass is biopsied and histopathology shows adenocarcinoma confined to the mucosa with no lymph node or distant metastasis. What is the most appropriate TNM stage of this tumor?

Stage 0. ### **Explanation** The correct answer is **Stage 0**. #### **1. Why Stage 0 is Correct** In the TNM staging of colorectal cancer, the depth of invasion is the primary determinant of the 'T' stage. * **Carcinoma in situ (Tis):** This is defined as cancer cells confined to the **mucosa** (epithelium or lamina propria) without extension through the **muscularis mucosae** into the submucosa. * Because the colonic mucosa lacks lymphatic channels (which begin in the submucosa), tumors confined to the mucosa have essentially **zero risk of regional lymph node metastasis**. * According to the AJCC staging system, **Tis N0 M0** is classified as **Stage 0**. #### **2. Why Other Options are Incorrect** * **Stage I (T1-T2 N0 M0):** Requires invasion into the **submucosa** (T1) or the **muscularis propria** (T2). * **Stage II (T3-T4 N0 M0):** Occurs when the tumor invades through the muscularis propria into the subserosa (T3) or perforates the visceral peritoneum/invades adjacent organs (T4), but without nodal involvement. * **Stage III (Any T, N1-N2 M0):** This stage is defined by the presence of **regional lymph node metastasis**, regardless of the depth of T invasion. #### **3. High-Yield Clinical Pearls for INI-CET** * **The "No Lymphatics" Rule:** Unlike the stomach or esophagus, the colonic lamina propria has no lymphatic vessels. Therefore, "intramucosal carcinoma" in the colon is biologically equivalent to carcinoma in situ. * **Management:** Most Stage 0 lesions can be managed via **endoscopic mucosal resection (EMR)** or polypectomy rather than formal colectomy, provided margins are clear. * **TNM Staging Quick Recall:** * **T1:** Submucosa * **T2:** Muscularis propria * **T3:** Subserosa/Pericolonic fat * **T4:** Perforation of serosa or invasion of other organs.

Question 1

Hereditary non-polyposis colorectal cancer (HNPCC) has an increased risk of all the following cancers except?

Accepted Answer

Pancreas

Answer

Endometrium

Answer

Ovary

Answer

Stomach

Question 2

Familial adenomatous polyposis is characterized by all of the following except:

Accepted Answer

Autosomal recessive transmission

Answer

More than 100 polyps in the colorectal area

Answer

Polyps seen in the duodenum

Answer

Extra-intestinal manifestations are present

Question 3

What is the most common site of perforation during colonoscopy?

Accepted Answer

Sigmoid colon

Answer

Cecum

Answer

Hepatic flexure

Answer

Splenic flexure

Question 4

Per rectum examination is not a useful test for the diagnosis of which of the following conditions?

Accepted Answer

Pilonidal sinus

Answer

Anal fissure

Answer

Hemorrhoid

Answer

Rectal ulcer

Question 5

A 33-year-old male presents with sudden onset acute abdominal pain, constipation for 1 day, persistent hiccups, and occasional vomiting. An abdominal X-ray was performed. Identify the pathology.

Accepted Answer

Sigmoid volvulus

Answer

Intussusception

Answer

Caecal volvulus

Answer

Mechanical obstruction

Question 6

A 70-year-old patient presents with absolute constipation and abdominal distension. The X-ray abdomen is given below. What is the most likely diagnosis?

Accepted Answer

Sigmoid Volvulus

Answer

Caecal Volvulus

Answer

Intestinal Obstruction

Answer

Small Bowel Volvulus

Question 7

A patient with grade 2 hemorrhoids underwent surgery, identify the instrument.

Accepted Answer

Haemorrhoids band kit

Answer

Stapler kit

Answer

CO2 laser

Answer

Haemorrhoids resection kit

Question 8

A homosexual man complains of painful defecation and mass protruding from the anal canal. Biopsy reveals squamous cell carcinoma of anus. Correct management for this patient is

Accepted Answer

Combined chemoradiation

Answer

Wide local excision

Answer

Chemotherapy

Answer

Abdominoperineal repair

Question 9

A man came with complaints of recurrent discharge and pain due to lesions around the anus for 3 years. A diagnosis of fistula-in-ano is made. What is the gold standard investigation for this condition?

Accepted Answer

MRI

Answer

Fistulogram

Answer

USG

Answer

CECT

Question 10

A 65-year-old patient undergoes colonoscopy for altered bowel habits. A 6 cm colonic mass is biopsied and histopathology shows adenocarcinoma confined to the mucosa with no lymph node or distant metastasis. What is the most appropriate TNM stage of this tumor?

Accepted Answer

Stage 0

Answer

Stage II

Answer

Stage III

Answer

Stage I

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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