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10. Pathology and Oncology MCQs

Practice Set 267 of 351

This practice set contains high-yield board review questions covering key concepts in 10. Pathology and Oncology. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 5321

Topic: 10. Pathology and Oncology

In the context of Enneking's staging, what does T1 signify for a malignant bone tumor?

. Tumor less than 5 cm
. Tumor confined within the cortex
. Tumor confined within the anatomical compartment
. Tumor involving adjacent anatomical compartments
. Tumor with skip lesions

Correct Answer & Explanation

. Tumor confined within the anatomical compartment

Explanation

For Enneking's local extent (T) classification, T1 indicates that the tumor is intracompartmental, meaning it is confined within the bone or the soft tissue compartment of origin. T2 signifies extracompartmental involvement, extending beyond the primary compartment.

Question 5322

Topic: 10. Pathology and Oncology
What is the most significant prognostic factor in the Enneking MSTS staging system for malignant bone tumors?
. Tumor size
. Histological subtype
. Age of the patient
. Presence of distant metastases
. Response to neoadjuvant chemotherapy

Correct Answer & Explanation

. Presence of distant metastases

Explanation

The presence of distant metastases (M1, leading to Stage III) is universally the most significant negative prognostic factor for musculoskeletal sarcomas, drastically reducing survival rates regardless of local grade or extent.

Question 5323

Topic: 10. Pathology and Oncology

An en bloc resection of a benign tumor with no gross tumor spillage but with microscopic tumor cells left behind at the margin of the pseudocapsule, would be classified as which Enneking surgical margin?

. Intralesional
. Marginal
. Wide
. Radical
. Incomplete

Correct Answer & Explanation

. Marginal

Explanation

A marginal excision removes the tumor and its surrounding pseudocapsule, or reactive zone, but the margin itself passes through this zone. This means microscopically, tumor cells might be left behind, even if macroscopically it appears complete.

Question 5324

Topic: 10. Pathology and Oncology
A biopsy reveals a high-grade undifferentiated pleomorphic sarcoma (G2) in the thigh, extending into multiple muscle compartments and encasing the femoral neurovascular bundle (T2). There are no distant metastases (M0). What is the Enneking stage?
. Stage IA
. Stage IB
. Stage IIA
. Stage IIB
. Stage III

Correct Answer & Explanation

. Stage IIB

Explanation

High-grade (G2), extracompartmental (T2), and no metastases (M0) classify this tumor as Enneking Stage IIB.

Question 5325

Topic: 10. Pathology and Oncology

Which of the following is an example of an aggressive (Stage 3) benign tumor according to Enneking's classification?

. Non-ossifying fibroma
. Osteochondroma
. Osteoid osteoma
. Aneurysmal bone cyst with rapid expansion and cortical breakthrough
. Unicameral bone cyst

Correct Answer & Explanation

. Aneurysmal bone cyst with rapid expansion and cortical breakthrough

Explanation

Stage 3 benign tumors are characterized by rapid, destructive growth, often with cortical breakthrough, soft tissue extension, and high recurrence rates. Aneurysmal bone cysts, particularly those that are rapidly expanding and breaching the cortex, can exhibit this aggressive behavior. The other options are typically Stage 1 or 2.

Question 5326

Topic: 10. Pathology and Oncology

What type of surgical margin is usually employed for Stage 1 (Latent) benign tumors, given their well-circumscribed nature and minimal growth potential?

. Intralesional excision or curettage
. Marginal excision
. Wide excision
. Radical resection
. Amputation

Correct Answer & Explanation

. Intralesional excision or curettage

Explanation

Stage 1 benign tumors, being latent and well-contained, are usually effectively treated with intralesional procedures such as curettage, as the goal is merely to remove the lesion without needing extensive healthy tissue margins.

Question 5327

Topic: 10. Pathology and Oncology
Following neoadjuvant chemotherapy, a high-grade osteosarcoma shows excellent tumor necrosis (>90%). How does this typically impact the required Enneking surgical margin for local control?
. Allows for a less aggressive intralesional margin
. May allow for a marginal margin if pre-op imaging showed good response
. Does not change the requirement for a wide surgical margin
. Necessitates an even wider margin due to concern for residual microscopic disease
. Converts the tumor to a benign classification

Correct Answer & Explanation

. Does not change the requirement for a wide surgical margin

Explanation

While excellent tumor necrosis after neoadjuvant chemotherapy is a positive prognostic indicator, it does not typically change the type of surgical margin required for a high-grade sarcoma. A wide surgical margin, aiming for microscopically clear tissue planes, remains the standard to achieve local control, as microscopic residual disease can persist even with good necrosis. The aim is still to resect through healthy tissue outside the reactive zone, which might have shrunk, but the principle of wide excision remains.

Question 5328

Topic: 10. Pathology and Oncology

Which characteristic defines a G2 tumor in the Enneking malignant staging system?

. Low histological grade
. High histological grade
. No metastatic potential
. Intracompartmental location
. Tumor < 8 cm

Correct Answer & Explanation

. High histological grade

Explanation

G2 signifies a high histological grade, indicating a tumor with high mitotic activity, pleomorphism, and generally an aggressive biological behavior. G1 denotes low histological grade.

Question 5329

Topic: 10. Pathology and Oncology
A biopsy of a soft tissue mass reveals a low-grade liposarcoma (G1). MRI shows the tumor is well-circumscribed and contained entirely within the adductor compartment of the thigh (T1). No distant metastases are identified (M0). What is the Enneking stage?
. Stage IA
. Stage IB
. Stage IIA
. Stage IIB
. Stage III

Correct Answer & Explanation

. Stage IA

Explanation

A low-grade tumor (G1) that is intracompartmental (T1) with no metastases (M0) is classified as Enneking Stage IA.

Question 5330

Topic: 10. Pathology and Oncology

For a Stage IIB malignant tumor, if a wide surgical margin is not achievable due to critical neurovascular involvement, what alternative surgical approach might be considered, potentially in conjunction with other therapies?

. Intralesional debulking
. Palliative resection only
. Marginal excision with radiation therapy
. Radical resection (e.g., amputation or limb disarticulation)
. Observation

Correct Answer & Explanation

. Radical resection (e.g., amputation or limb disarticulation)

Explanation

If a wide surgical margin cannot be safely achieved while preserving limb function for a high-grade, extracompartmental tumor (Stage IIB), a radical resection, such as amputation or disarticulation, might be the only way to achieve adequate local control by removing the entire involved compartment.

Question 5331

Topic: 10. Pathology and Oncology
Which of the following scenarios would lead to an immediate Enneking Stage III classification for a malignant tumor?
. High-grade tumor with large extracompartmental extension
. Low-grade tumor with skip lesions
. Any tumor with lung metastases
. Tumor recurrence after initial wide excision
. Tumor involving two adjacent anatomical compartments

Correct Answer & Explanation

. Any tumor with lung metastases

Explanation

The presence of distant metastases (M1), such as lung metastases, automatically classifies any malignant tumor as Enneking Stage III, regardless of its grade or local extent.

Question 5332

Topic: 10. Pathology and Oncology

What is the primary determinant of tumor 'T' stage (T1 vs T2) in the Enneking system for bone sarcomas?

. Tumor size in centimeters
. Cortical integrity
. Involvement of adjacent joints
. Intracompartmental vs. extracompartmental extension
. Presence of pathological fracture

Correct Answer & Explanation

. Intracompartmental vs. extracompartmental extension

Explanation

The 'T' stage (local extent) in Enneking's system primarily differentiates based on whether the tumor is contained within its anatomical compartment (T1, intracompartmental) or has extended beyond it (T2, extracompartmental). Cortical integrity and pathological fracture are aspects that contribute to determining T stage, but the overarching principle is compartmental confinement.

Question 5333

Topic: 10. Pathology and Oncology
A biopsy indicates a low-grade chondrosarcoma (G1). Imaging shows the tumor has extended through the cortex into the adjacent soft tissues but remains relatively contained within the periosseous reactive zone (T2). No metastases are found (M0). What is the Enneking stage?
. Stage IA
. Stage IB
. Stage IIA
. Stage IIB
. Stage III

Correct Answer & Explanation

. Stage IB

Explanation

A low-grade tumor (G1) that is extracompartmental (T2) and without metastases (M0) is classified as Enneking Stage IB.

Question 5334

Topic: 10. Pathology and Oncology

For a Stage 2 (Active) benign tumor, such as a symptomatic enchondroma with cortical expansion, what is the most appropriate surgical margin according to Enneking principles?

. Intralesional curettage
. Marginal excision
. Wide excision
. Radical resection
. Observation

Correct Answer & Explanation

. Intralesional curettage

Explanation

Stage 2 benign tumors are locally active and progressive, often requiring more thorough removal than Stage 1 lesions. However, they are still typically treated with intralesional curettage, often augmented with adjuvant therapy (e.g., cryotherapy, phenol) to reduce recurrence rates, as they do not invade healthy tissue in the way malignant tumors do.

Question 5335

Topic: 10. Pathology and Oncology

What defines a surgical margin as 'intralesional' in Enneking's classification?

. The plane of dissection passes through the reactive zone of the tumor.
. The plane of dissection passes through healthy tissue outside the reactive zone.
. The plane of dissection passes directly through the tumor tissue itself.
. The entire anatomical compartment containing the tumor is removed.
. The tumor is simply debulked without a clear margin.

Correct Answer & Explanation

. The plane of dissection passes directly through the tumor tissue itself.

Explanation

An intralesional margin implies that the surgical incision or plane of dissection enters and passes through the tumor mass itself, resulting in macroscopic tumor being left behind or gross contamination of the wound.

Question 5336

Topic: 10. Pathology and Oncology

When evaluating the local extent (T-stage) of a bone tumor, which imaging modality is generally superior for determining compartmental involvement and soft tissue extension?

. Plain radiographs
. CT scan
. Bone scintigraphy
. MRI with contrast
. Ultrasound

Correct Answer & Explanation

. MRI with contrast

Explanation

MRI with contrast is superior for evaluating soft tissue involvement, marrow extension, neurovascular compromise, and assessing compartmental boundaries, all crucial for accurate T-staging in the Enneking system and surgical planning.

Question 5337

Topic: 10. Pathology and Oncology

A surgeon performs an intralesional curettage for a giant cell tumor. What is the expected Enneking surgical margin outcome?

. Wide
. Marginal
. Intralesional
. Radical
. Clear

Correct Answer & Explanation

. Intralesional

Explanation

Intralesional curettage, by definition, means that the tumor is scooped out, and the plane of dissection is within the tumor itself. This is an intralesional margin and invariably leaves microscopic, if not macroscopic, tumor cells behind.

Question 5338

Topic: 10. Pathology and Oncology

Which of the following benign tumors is most likely to be classified as Stage 3 (Aggressive) and require a marginal or wide excision?

. Fibrous dysplasia
. Osteochondroma
. Desmoid tumor (extra-abdominal)
. Unicameral bone cyst
. Non-ossifying fibroma

Correct Answer & Explanation

. Desmoid tumor (extra-abdominal)

Explanation

Desmoid tumors, though histologically benign, are locally aggressive, infiltrative, and have a high local recurrence rate. They often necessitate marginal or even wide excisions to achieve local control, aligning with the characteristics of an Enneking Stage 3 benign tumor.

Question 5339

Topic: 10. Pathology and Oncology

According to the Enneking system, what is the 'reactive zone' surrounding a tumor?

. The zone of necrotic tissue within the tumor itself.
. The area of healthy tissue immediately adjacent to the tumor, free of tumor cells.
. A layer of compressed normal tissue and granulation tissue that forms around a tumor.
. The region where chemotherapy has induced tumor regression.
. The area of bone sclerosis seen on radiographs.

Correct Answer & Explanation

. A layer of compressed normal tissue and granulation tissue that forms around a tumor.

Explanation

The reactive zone is a layer of compressed normal tissue, edema, and granulation tissue that forms a biological barrier around the tumor (or its pseudocapsule). It often contains microscopic tumor extensions, making it an unsafe plane for marginal excision of malignant lesions.

Question 5340

Topic: 10. Pathology and Oncology

What is the primary purpose of pathological evaluation of surgical margins after tumor resection?

. To confirm the tumor diagnosis.
. To determine the Enneking stage retrospectively.
. To assess the adequacy of the surgical procedure in achieving local control.
. To predict the patient's long-term survival.
. To guide systemic chemotherapy decisions.

Correct Answer & Explanation

. To assess the adequacy of the surgical procedure in achieving local control.

Explanation

Pathological evaluation of surgical margins is crucial to assess if tumor cells are present at the edge of the resected specimen. A positive margin indicates inadequate resection and increases the risk of local recurrence, thereby guiding decisions for further surgery or adjuvant radiotherapy to achieve local control.

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