Sentinel Lymph Node Concepts Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Sentinel Lymph Node Concepts. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Sentinel Lymph Node Concepts Indian Medical PG Question 1: Which of the following stages of Breast Cancer corresponds to the following features: a breast mass of 6 x 3 cm, ipsilateral supraclavicular lymph node involvement, and distant metastasis that cannot be assessed?
- A. T4 N3 MX
- B. T4 N1 M1
- C. T4 N0 M0
- D. T3 N3c MX (Correct Answer)
Sentinel Lymph Node Concepts Explanation: ***T3 N3c MX***
- A **breast mass of 6 x 3 cm** indicates a T3 tumor (tumor size > 5 cm).
- **Ipsilateral supraclavicular lymph node involvement** is classified as N3c disease. **Distant metastasis that cannot be assessed** is denoted by MX.
*T4 N3 MX*
- A **T4 classification** is reserved for tumors with direct extension to the chest wall or skin, or inflammatory breast cancer, which is not mentioned here.
- While N3c and MX are correct for the nodal and metastatic status, the T stage is inaccurate based on the provided tumor size.
*T4 N1 M1*
- A **T4 classification** is incorrect as the mass size alone (6 x 3 cm) does not meet T4 criteria.
- **N1** denotes involvement of 1-3 axillary lymph nodes, which is less extensive than supraclavicular involvement (N3c). **M1** indicates confirmed distant metastasis, but the question states it "cannot be assessed" (MX).
*T4 N0 M0*
- **T4** is incorrect, as this stage is for direct chest wall/skin involvement or inflammatory breast cancer.
- **N0** signifies no regional lymph node metastasis, contradicting the presence of supraclavicular lymph node involvement. **M0** indicates no distant metastasis, whereas the question specifies it cannot be assessed (MX).
Sentinel Lymph Node Concepts Indian Medical PG Question 2: A 45-year-old woman with early-stage breast cancer is discussing treatment options with her surgeon. Which of the following statements regarding breast conservation surgery is NOT true?
- A. Post-operative radiotherapy
- B. Axillary dissection (Correct Answer)
- C. Wide local excision
- D. Sentinel lymph node biopsy
Sentinel Lymph Node Concepts Explanation: ***Axillary dissection***
- **Axillary dissection is NOT a routine component of breast conservation surgery** for early-stage breast cancer.
- In early-stage disease, **sentinel lymph node biopsy (SLNB)** has largely replaced routine axillary dissection as it provides accurate staging with significantly less morbidity.
- Axillary dissection is only performed when there is **proven extensive lymph node involvement** or when SLNB shows metastatic disease requiring further assessment.
- Therefore, this statement is **NOT true** regarding routine breast conservation surgery.
*Wide local excision*
- **Wide local excision (lumpectomy)** is the primary surgical component of breast conservation therapy.
- It involves removing the cancerous tumor along with a margin of healthy breast tissue to achieve clear margins while preserving the breast.
*Sentinel lymph node biopsy*
- **SLNB** is a standard procedure performed with breast conservation surgery to assess for regional lymph node metastasis.
- It identifies and removes the first few lymph nodes draining the tumor, allowing accurate staging with minimal morbidity.
*Post-operative radiotherapy*
- **Post-operative radiotherapy** to the preserved breast is a critical and essential component of breast conservation therapy.
- It significantly reduces the risk of local recurrence by treating any microscopic tumor cells that may remain after surgery.
Sentinel Lymph Node Concepts Indian Medical PG Question 3: Sentinel lymph node biopsy is most useful for:
- A. Carcinoma vulva (Correct Answer)
- B. Carcinoma endometrium
- C. Carcinoma vagina
- D. Carcinoma cervix
Sentinel Lymph Node Concepts Explanation: ***Carcinoma vulva***
- **Sentinel lymph node biopsy (SLNB)** is a standard procedure for early-stage vulvar carcinoma to assess nodal involvement with less morbidity than full inguinofemoral lymphadenectomy.
- The procedure helps identify metastases in regional lymph nodes, guiding further treatment decisions while minimizing complications like **lymphedema**.
*Carcinoma endometrium*
- While SLNB can be used in endometrial cancer, its primary utility is in tailoring **lymphadenectomy** rather than being the "most useful" or universally preferred primary staging tool compared to vulvar cancer.
- The anatomical spread often involves different lymphatic basins, and **comprehensive pelvic and para-aortic lymphadenectomy** or systematic nodal dissection remains a common approach, though SLNB is gaining traction.
*Carcinoma vagina*
- The lymphatic drainage of the vagina is complex and variable, making SLNB challenging and less standardized compared to vulvar cancer.
- **Radical surgical excision** with **regional lymphadenectomy** remains the mainstay for staging and treatment of invasive vaginal carcinoma.
*Carcinoma cervix*
- For cervical cancer, SLNB is primarily used in **early-stage disease** to detect micrometastases and guide the extent of lymph node dissection.
- However, **imaging** and comprehensive **pelvic lymphadenectomy** are often still crucial components for complete staging and treatment, depending on tumor characteristics.
Sentinel Lymph Node Concepts Indian Medical PG Question 4: Among the following, intraoperative sentinel lymph node detection in axilla can be done using
- A. Mammography
- B. Isosulfan blue dye (Correct Answer)
- C. MRI
- D. CT
Sentinel Lymph Node Concepts Explanation: ***Correct Option: Isosulfan blue dye***
- **Isosulfan blue dye** is a vital dye used for **intraoperative visual identification** of sentinel lymph nodes in the axilla during breast cancer surgery
- The dye is injected near the tumor site and **preferentially concentrates in lymphatic channels**, allowing the surgeon to visually trace the lymphatic drainage to the **first lymph node(s)** (sentinel nodes) receiving lymph flow
- The sentinel nodes appear **blue-stained** and can be identified and excised for biopsy to determine lymph node status
- **Alternative methods** include radioactive tracers like **Technetium-99m** or a combination of both (dual mapping technique)
*Incorrect Option: Mammography*
- Mammography is an **X-ray imaging technique** used for breast cancer screening and diagnosis to detect tumors and calcifications
- It is a **pre-operative diagnostic tool**, not used for intraoperative sentinel lymph node detection
- Cannot visualize or track lymphatic flow during surgery
*Incorrect Option: MRI*
- MRI (Magnetic Resonance Imaging) provides detailed anatomical assessment and staging of breast cancer pre-operatively
- It is a **static imaging modality** that cannot be used for real-time intraoperative sentinel lymph node detection
- Does not visualize lymphatic drainage or dye uptake during surgery
*Incorrect Option: CT*
- CT scans (Computed Tomography) provide cross-sectional images useful for assessing tumor size and metastatic spread
- Not employed for **intraoperative sentinel lymph node detection**
- Cannot track real-time lymphatic flow with dyes during surgery
Sentinel Lymph Node Concepts Indian Medical PG Question 5: A 40-year-old patient is diagnosed with a localized 1 cm infiltrating ductal cancer after a needle core biopsy of the lesion. She is clinical node negative; a lumpectomy and sentinel lymph node biopsy are performed. The patient develops an anaphylactic response during the case. Which of the following substances was the likely causative agent?
- A. Isosulfan blue dye (Correct Answer)
- B. Patent blue dye
- C. 99 Tc radiolabeled colloid
- D. Methylene blue dye
Sentinel Lymph Node Concepts Explanation: ***Isosulfan blue dye***
- **Isosulfan blue dye** is commonly used in sentinel lymph node biopsy procedures for its ability to stain lymphatic channels, but it carries the **highest risk of anaphylactic reactions** among lymphatic mapping agents.
- The incidence of anaphylaxis with isosulfan blue ranges from **0.07-2%**, significantly higher than other tracers.
- The patient's development of an **anaphylactic response** during the case strongly points to isosulfan blue as the causative agent due to its documented allergenicity.
*Patent blue dye*
- **Patent blue dye** is another lymphatic mapping dye used for sentinel lymph node biopsy, particularly in European practice.
- While it can also cause allergic reactions, the incidence of **severe anaphylaxis** is lower than with isosulfan blue, making it a less likely culprit in this case.
- Patent blue and isosulfan blue are structurally similar, but isosulfan blue has higher reported anaphylaxis rates in clinical practice.
*99 Tc radiolabeled colloid*
- **Technetium-99m (99mTc) radiolabeled colloid** is widely used in sentinel lymph node mapping due to its excellent lymphatic tracking and low incidence of allergic reactions.
- Anaphylaxis to **radiopharmaceuticals** is extremely rare compared to reactions to blue dyes, with virtually no reported cases during SLNB.
*Methylene blue dye*
- **Methylene blue dye** is an alternative to isosulfan blue for sentinel lymph node mapping, especially in patients with a history of isosulfan blue allergy.
- While allergic reactions can occur, **methylene blue** is generally associated with a significantly lower incidence of severe anaphylaxis than isosulfan blue.
Sentinel Lymph Node Concepts Indian Medical PG Question 6: A tumor in the cheek measuring 3 cm in size with contralateral mobile lymph nodes comes under:
- A. T3N3M0
- B. T2N2M0 (Correct Answer)
- C. T3N2M0
- D. T4N2M0
Sentinel Lymph Node Concepts Explanation: ***T2N2M0***
- A 3 cm tumor in the cheek is classified as **T2** for head and neck cancers, which designates a tumor greater than 2 cm but not exceeding 4 cm.
- **Contralateral mobile lymph nodes** are classified as **N2c** if bilateral or contralateral nodes are involved and are ≤6 cm and mobile, which falls under the broader N2 classification.
*T3N3M0*
- **T3** generally refers to a tumor greater than 4 cm or with specific features like bone invasion in some sites, neither of which is present here.
- **N3** indicates a lymph node greater than 6 cm in greatest dimension, or involving supraclavicular nodes, which is not described.
*T3N2M0*
- As explained, a 3 cm tumor is a **T2**, not a T3.
- **N2** applies to the contralateral mobile lymph nodes, but the tumor size is incorrect for a T3 classification.
*T4N2M0*
- **T4** indicates a very large tumor (often >4 cm) or one with extensive invasion into adjacent structures, which is not the case for a 3 cm cheek tumor.
- While **N2** may apply to the nodes, the T classification is incorrect.
Sentinel Lymph Node Concepts Indian Medical PG Question 7: Indication for sentinel node biopsy is:
- A. Palpable axillary lymph node
- B. Metastasis
- C. Mass > 5 cm
- D. Non-palpable axillary lymph node (Correct Answer)
Sentinel Lymph Node Concepts Explanation: ***Non-palpable axillary lymph node***
- **Sentinel lymph node biopsy (SLNB)** is indicated when there is no clinical evidence of axillary lymph node involvement, meaning the nodes are **non-palpable**.
- Its purpose is to identify micrometastases that would not be detectable by physical examination, staging the cancer more accurately and guiding further treatment.
*Palpable axillary lymph node*
- A **palpable axillary lymph node** suggests macroscopic nodal involvement, usually requiring a fine needle aspiration (FNA) or core needle biopsy for diagnosis.
- If positive, these patients typically proceed directly to **axillary lymph node dissection (ALND)** rather than SLNB.
*Mass > 5 cm*
- The size of the primary tumor (e.g., > 5 cm) is a factor in staging but does not, in itself, preclude or indicate SLNB.
- While larger tumors have a higher risk of nodal involvement, the decision for SLNB still hinges on the clinical status of the axilla (palpable vs. non-palpable nodes).
*Metastasis*
- If **distant metastasis** is confirmed, the focus shifts to palliative care and systemic treatment, making a regional staging procedure like SLNB less relevant or unnecessary.
- SLNB is used for staging early-stage cancer to detect regional spread, not when widespread disease is already established.
Sentinel Lymph Node Concepts Indian Medical PG Question 8: Urinary bladder can be injured in all of the following operations EXCEPT:
- A. Surgery for rectum
- B. Inguinal hernia repair (Correct Answer)
- C. Inguinal lymph node dissection
- D. Hysterectomy
Sentinel Lymph Node Concepts Explanation: ***Inguinal hernia repair***
- While theoretically possible, bladder injury during **inguinal hernia repair** is exceedingly rare, often less than 1% as the bladder is not typically in the direct field of dissection.
- The surgical approach for inguinal hernias generally involves layers superficial to the bladder, making direct injury much less common than in pelvic surgeries.
- Rare cases occur with **sliding hernias** where the bladder may form part of the hernia sac wall.
*Surgery for rectum*
- **Anterior resection of the rectum** or abdominoperineal resection involves dissecting close to the bladder's posterior and inferior aspects, particularly the **bladder base** and **ureteral entries**.
- Procedures like low anterior resection for rectal cancer pose a significant risk due to the **proximity of the bladder** to the surgical field in the pelvis.
*Inguinal lymph node dissection*
- **Inguinal lymph node dissection** is primarily a superficial groin procedure involving removal of superficial and deep inguinal nodes.
- While bladder injury is **theoretically possible** if dissection extends unusually deep or medially toward the retropubic space, this is **extremely rare** in standard practice.
- The risk is significantly lower than pelvic operations but higher than standard inguinal hernia repair due to the extent of dissection.
*Hysterectomy*
- During a **hysterectomy** (removal of the uterus), the bladder lies anterior and inferior to the uterus and cervix, making it highly susceptible to injury.
- The dissection planes for detaching the bladder from the lower uterine segment and cervix pose a substantial risk, especially during **total abdominal hysterectomy** or **vaginal hysterectomy**.
- This is one of the **most common** causes of iatrogenic bladder injury.
Sentinel Lymph Node Concepts Indian Medical PG Question 9: Sentinel lymph node biopsy in carcinoma breast is done if -
- A. LN palpable
- B. Breast lump with palpable axillary node
- C. Metastatic CA breast
- D. Breast mass but no lymph node palpable (Correct Answer)
Sentinel Lymph Node Concepts Explanation: ***Breast mass but no lymph node palpable***
- Sentinel lymph node biopsy is primarily performed in patients with **clinically negative axillae** (no palpable lymph nodes) to assess for microscopic metastatic disease.
- The goal is to avoid full axillary lymph node dissection if the sentinel nodes are negative, thus reducing the risk of **lymphedema** and other complications.
*LN palpable*
- If a lymph node is palpable, it is often considered **clinically suspicious** and may warrant a direct fine-needle aspiration (FNA) or core biopsy rather than a sentinel node biopsy.
- A positive biopsy from a palpable node would typically lead directly to an **axillary lymph node dissection** or neoadjuvant therapy, as the sentinel node procedure offers less benefit in this scenario.
*Breast lump with palpable axillary node*
- Similar to a palpable LN, a **palpable axillary node** in the presence of a breast lump suggests established nodal involvement.
- In such cases, **sentinel lymph node biopsy** is often not the initial step; rather, direct biopsy of the palpable node or upfront axillary dissection (sometimes after neoadjuvant treatment) is considered.
*Metastatic CA breast*
- In **metastatic breast cancer** (stage IV disease), the focus shifts to systemic treatment, and axillary lymph node dissection, including sentinel node biopsy, is generally not indicated for staging purposes.
- The primary goal is palliative care or controlling systemic disease, not regional lymph node staging.
Sentinel Lymph Node Concepts Indian Medical PG Question 10: Dye for Sentinel Lymph Node Biopsy is injected in which of the following sites?
- A. Nipple
- B. Axilla
- C. Areola (Correct Answer)
- D. Tail of spence
Sentinel Lymph Node Concepts Explanation: ***Areola***
- The **areola** is the primary site for injecting dye in sentinel lymph node biopsy because it is rich in **lymphatic vessels** that directly drain into the regional lymph nodes.
- This method ensures the dye follows the natural lymphatic drainage pathway, accurately identifying the **first lymph node** to receive drainage from the tumor.
*Nipple*
- While the nipple is part of the breast, it has a less dense network of **lymphatic vessels** compared to the areola.
- Injection directly into the nipple may not consistently identify the sentinel lymph node as effectively as periareolar or intratumoral injections.
*Axilla*
- The **axilla** contains the regional lymph nodes that are the *target* for identification, not the site of dye injection.
- Injecting dye directly into the axilla would bypass the lymphatic drainage from the tumor, making the biopsy ineffective.
*Tail of spence*
- The **tail of Spence** is an extension of breast tissue into the axilla, and while it contains breast tissue, it is not the most optimal or primary site for dye injection.
- The lymphatic drainage from the tail of Spence would still rely on the broader lymphatic network, which is best accessed via the central breast regions like the areola.
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