Oncological Surgery Practice Questions

Q: Which of the following requires the maximum margin of excision?

Dermatofibrosarcoma protuberans. **Explanation:** The correct answer is **Dermatofibrosarcoma Protuberans (DFSP)**. The primary factor determining excision margins is the biological behavior and local invasiveness of the tumor. DFSP is a low-to-intermediate grade cutaneous sarcoma characterized by extensive, subclinical **tentacle-like lateral extensions** (microscopic projections) into the surrounding dermis and subcutaneous fat. Because these extensions often go beyond the clinically visible tumor, standard narrow margins lead to extremely high recurrence rates. Current guidelines recommend a wide local excision with a margin of **2 to 4 cm**, or ideally, Mohs Micrographic Surgery (MMS). **Analysis of Incorrect Options:** * **Malignant Melanoma:** Margins are determined by the **Breslow thickness**. Even for the thickest tumors (>2 mm), the maximum recommended margin is **2 cm**. * **Squamous Cell Carcinoma (SCC):** Standard margins for high-risk SCC are typically **6 mm to 10 mm**. * **Basal Cell Carcinoma (BCC):** This is the least aggressive of the group. Standard excision margins are usually **4 mm to 5 mm** for low-risk lesions. **High-Yield Clinical Pearls for NEET-PG:** * **DFSP Pathognomonic Feature:** Histology shows a characteristic **"storiform" (cartwheel) pattern** of spindle cells and a **"honeycomb" appearance** when invading subcutaneous fat. * **Cytogenetics:** Associated with a translocation **t(17;22)**, leading to overexpression of PDGFB. * **Treatment of Choice:** Mohs Micrographic Surgery (MMS) is preferred over wide local excision to minimize tissue loss while ensuring clear margins. * **Medical Management:** **Imatinib** (a tyrosine kinase inhibitor) is used for metastatic or unresectable DFSP.

Q: The staging system for thymoma was developed by whom?

Masaoka. The correct answer is **A. Masaoka**. ### Explanation The staging of thymic epithelial tumors (thymomas) is primarily based on the **Masaoka Staging System** (later modified as the Masaoka-Koga system). This system is unique because it is based on the degree of **capsular invasion** and the involvement of adjacent structures rather than just tumor size. * **Stage I:** Macroscopically and microscopically completely encapsulated. * **Stage II:** Microscopic transcapsular invasion (IIa) or macroscopic invasion into surrounding fatty tissue (IIb). * **Stage III:** Macroscopic invasion into neighboring organs (pericardium, great vessels, or lungs). * **Stage IV:** Pleural/pericardial dissemination (IVa) or lymphogenous/hematogenous metastasis (IVb). ### Why the other options are incorrect: * **B. Yokohama:** This is not a recognized surgical staging system. It is likely a distractor. * **C. Todani:** This classification is used for **Choledochal cysts** (Types I-V), a high-yield topic in pediatric and hepatobiliary surgery. * **D. Klatskin (often confused with Kluive):** While "Kluive" is a distractor, **Klatskin tumors** refer to hilar cholangiocarcinoma. If the option meant **Bismuth-Corlette**, that is the staging used for those tumors. ### High-Yield Clinical Pearls for NEET-PG: 1. **Most common association:** 30–45% of patients with thymoma have **Myasthenia Gravis**. Conversely, only 10–15% of patients with Myasthenia Gravis have a thymoma. 2. **Treatment of Choice:** Complete surgical resection (**En-bloc Thymectomy**) is the gold standard for resectable tumors. 3. **WHO Classification:** While Masaoka stages the *extent*, the WHO classification (Types A, AB, B1, B2, B3, and C) categorizes thymomas based on *histology* and cytological atypia. 4. **TNM Staging:** Recently, the AJCC/UICC 8th edition introduced a TNM staging system for thymic tumors, but Masaoka-Koga remains the most widely used in clinical practice.

Q: What is the recommended treatment for papillary carcinoma of the thyroid with bony metastasis?

Near total thyroidectomy with radioiodine and radiotherapy. ### Explanation The management of differentiated thyroid cancers (DTC), specifically **Papillary Carcinoma Thyroid (PTC)** with distant metastasis, follows a multimodal approach aimed at both local control and systemic treatment. **Why Option D is Correct:** 1. **Near Total or Total Thyroidectomy:** This is the mandatory first step. Removing all normal thyroid tissue is essential to eliminate the source of thyroglobulin (a tumor marker) and, more importantly, to ensure that subsequent doses of radioactive iodine (RAI) are taken up by the metastatic bone lesions rather than the thyroid gland itself. 2. **Radioiodine (I-131) Therapy:** PTC is typically iodine-avid. RAI is the treatment of choice for distant metastases (lung and bone) after the primary gland is removed. 3. **Radiotherapy (EBRT):** Bone metastases in PTC are often osteolytic and carry a high risk of pathological fractures or spinal cord compression. External Beam Radiation Therapy (EBRT) is added for palliation, pain control, and to stabilize the metastatic site. **Analysis of Incorrect Options:** * **Options A & B:** These are incomplete. Surgery is the cornerstone of management for DTC, even in the presence of metastasis, to facilitate adjuvant therapies. * **Option C:** While it includes surgery and radiotherapy, it misses **Radioiodine**, which is the most specific systemic therapy for thyroid cancer cells. **NEET-PG High-Yield Pearls:** * **Most common site of metastasis in PTC:** Cervical lymph nodes (Level II, III, IV). * **Most common site of distant metastasis:** Lungs (more common than bone). * **Prognostic Scoring:** Use the **AMES** or **MACIS** criteria for PTC. * **Thyroglobulin (Tg):** Used as a postoperative tumor marker to monitor recurrence. * **Treatment of choice for Follicular Carcinoma with bone metastasis:** Also Total Thyroidectomy followed by RAI.

Q: A 3 cm squamous cell carcinoma of the retrornolar trigone is invading the mandible and the medial pterygoid muscle. What is the TNM stage of this tumor?

Stage IV. ### Explanation The TNM staging for Oral Cavity cancers (including the retromolar trigone) is based on the size and depth of invasion (T), nodal involvement (N), and metastasis (M). **1. Why Stage IV is Correct:** According to the AJCC 8th Edition, the T-stage is determined by the extent of local invasion. * **T4a (Moderately Advanced Local Disease):** The tumor invades adjacent structures such as the cortical bone of the mandible or maxilla, deep (extrinsic) muscles of the tongue, maxillary sinus, or skin of the face. * **T4b (Very Advanced Local Disease):** The tumor invades the masticator space (which includes the **medial pterygoid muscle**), pterygoid plates, or skull base, and/or encases the internal carotid artery. In this case, invasion into the **medial pterygoid muscle** automatically classifies the tumor as **T4b**. Any T4 tumor (T4a or T4b) with any N or M status results in a **Stage IV** designation (specifically Stage IVB for T4b). **2. Why Other Options are Incorrect:** * **Stage I:** Requires a T1 tumor (≤2 cm and Depth of Invasion [DOI] ≤5 mm) with no nodal involvement. * **Stage II:** Requires a T2 tumor (>2 cm and ≤4 cm, DOI ≤10 mm) with no nodal involvement. * **Stage III:** Requires a T3 tumor (>4 cm or DOI >10 mm) or a T1/T2/T3 tumor with a single ipsilateral lymph node ≤3 cm (N1). **3. Clinical Pearls for NEET-PG:** * **Retromolar Trigone (RMT):** A unique site where the mucosa is closely attached to the bone; hence, early bone invasion is common. * **Masticator Space:** Involvement of the medial pterygoid often presents clinically as **trismus** (lockjaw), which is a "red flag" for T4b disease. * **Bone Invasion:** Superficial erosion of bone/tooth socket by a gingival primary is not enough to classify as T4; there must be invasion through the cortical bone.

Question 1

Which of the following requires the maximum margin of excision?

Accepted Answer

Dermatofibrosarcoma protuberans

Answer

Malignant melanoma

Answer

Basal cell carcinoma (BCC)

Answer

Squamous cell carcinoma (SCC)

Question 2

The staging system for thymoma was developed by whom?

Accepted Answer

Masaoka

Answer

Yokohama

Answer

Todani

Answer

Kluive

Question 3

What is the recommended treatment for papillary carcinoma of the thyroid with bony metastasis?

Accepted Answer

Near total thyroidectomy with radioiodine and radiotherapy

Answer

Radiotherapy

Answer

Radioiodine

Answer

Near total thyroidectomy with radiotherapy

Question 4

A 3 cm squamous cell carcinoma of the retrornolar trigone is invading the mandible and the medial pterygoid muscle. What is the TNM stage of this tumor?

Accepted Answer

Stage IV

Answer

Stage I

Answer

Stage II

Answer

Stage III

Question 5

A 42-year-old man is undergoing chemotherapy after resection of a cecal adenocarcinoma with positive lymph nodes. Which of the following potentially operable complications is a common occurrence among patients receiving systemic chemotherapy?

Accepted Answer

Perirectal abscess

Answer

Acute cholecystitis

Answer

Appendicitis

Answer

Diverticulitis

Oncological Surgery — MCQs

Oncological Surgery — MCQs

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