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10. Pathology and Oncology MCQs

Practice Set 198 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 3941

Topic: 10. Pathology and Oncology

A 70-year-old male with a history of chronic alcoholism and liver cirrhosis develops a painful, enlarging mass in his proximal humerus. Biopsy reveals epithelioid hemangioendothelioma. Staging shows no regional lymph node or distant metastases. Given the primary tumor's aggressive local growth potential, what is the typical surgical margin required for definitive treatment of this primary bone tumor?

. Intralesional
. Marginal
. Wide
. Radical
. Contaminated

Correct Answer & Explanation

. Wide

Explanation

Epithelioid hemangioendothelioma, despite its often low-grade histological appearance, can behave aggressively with a tendency for local recurrence and multifocal presentation. For definitive treatment of primary bone tumors considered malignant or with significant aggressive potential, a 'wide' surgical margin is generally required. A wide margin involves removing the tumor en bloc with a cuff of healthy normal tissue completely surrounding the lesion. Marginal excision risks local recurrence for such lesions. Intralesional is for benign tumors or palliative care. Radical excision involves removal of an entire anatomical compartment (e.g., amputation), which may be necessary in extreme cases but is not the general requirement for all malignant bone tumors if wide excision is achievable. Contaminated margins are not a goal.

Question 3942

Topic: 10. Pathology and Oncology

A 10-year-old female presents with severe pain and swelling in her right tibia. Biopsy confirms Ewing sarcoma. Staging studies reveal extensive metastatic disease to the lungs and multiple bones. What is the most critical prognostic factor for this patient, beyond the primary tumor characteristics?

. Patient age
. Tumor size
. Location of primary tumor
. Presence and extent of metastatic disease
. Response to neoadjuvant chemotherapy

Correct Answer & Explanation

. Presence and extent of metastatic disease

Explanation

For Ewing sarcoma, as with most aggressive sarcomas, the presence and extent of metastatic disease at presentation is the single most critical prognostic factor. Patients with localized disease have significantly better survival rates than those with metastatic disease. While age, tumor size, and location are also important prognostic indicators for localized disease, the presence of widespread metastases fundamentally alters the prognosis. Response to neoadjuvant chemotherapy is crucial for localized disease but is not a primary factorat presentationwhen metastases are already identified.

Question 3943

Topic: 10. Pathology and Oncology

Which of the following is generally considered a contraindication to limb-salvage surgery for a primary high-grade bone sarcoma of the extremity?

. Pathological fracture through the tumor
. Pediatric patient with open physes
. Proximity to a major nerve
. Extensive neurovascular bundle involvement not amenable to reconstruction
. Large tumor size (>10 cm)

Correct Answer & Explanation

. Extensive neurovascular bundle involvement not amenable to reconstruction

Explanation

Extensive involvement of the neurovascular bundle that precludes a wide margin resection without sacrificing critical neurovascular structures, and where reconstruction is not feasible or would result in a non-functional limb, is generally a contraindication to limb-salvage surgery. In such cases, amputation may be necessary to achieve oncologic clearance and a functional outcome. While a pathological fracture can complicate limb salvage, it is not an absolute contraindication if soft tissue contamination can be managed. Open physes in children require careful consideration but do not contraindicate limb salvage (often addressed with expandable prostheses or growth-sparing techniques). Proximity to a major nerve can be challenging but is often managed with meticulous dissection or nerve grafting if necessary, not an absolute contraindication. Large tumor size makes limb salvage more difficult but is not an absolute contraindication if oncologic margins and functional outcomes can be achieved.

Question 3944

Topic: 10. Pathology and Oncology

A 45-year-old male undergoes wide local excision for a 6 cm high-grade myxofibrosarcoma of the forearm. Pathological review reveals tumor at the deep margin (R1 resection). What is the most appropriate next step in management?

. Observation with close follow-up
. Systemic chemotherapy
. Adjuvant radiation therapy to the tumor bed
. Repeat wide local excision
. Amputation of the forearm

Correct Answer & Explanation

. Repeat wide local excision

Explanation

For soft tissue sarcomas, a positive surgical margin (R1: microscopic tumor at margin; R2: macroscopic tumor at margin) is a strong predictor of local recurrence. The primary goal is to achieve negative margins (R0). Therefore, the most appropriate next step after an R1 resection of a high-grade soft tissue sarcoma is typically a re-excision to obtain clear margins, if technically feasible without unacceptable morbidity. If re-excision is not possible or carries significant risk, then adjuvant radiation therapy may be considered, but re-excision is generally preferred for achieving local control. Chemotherapy is not typically indicated for local control of R1 resections. Amputation is usually reserved for unresectable tumors or recurrent disease after multiple attempts at limb salvage.

Question 3945

Topic: 10. Pathology and Oncology

Which histological subtype of primary bone sarcoma is most commonly associated with a preceding history of Paget's disease of bone?

. Osteosarcoma
. Chondrosarcoma
. Ewing sarcoma
. Fibrosarcoma
. Giant cell tumor of bone

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common primary malignant bone tumor to arise in bone affected by Paget's disease (Paget's sarcoma). These are typically high-grade, aggressive osteosarcomas occurring in older patients, often presenting in the femur, pelvis, or humerus. While other sarcomas can rarely occur, osteosarcoma is by far the most recognized association.

Question 3946

Topic: 10. Pathology and Oncology
A patient with osteosarcoma of the proximal tibia has an excellent response to neoadjuvant chemotherapy, with >90% tumor necrosis on post-chemotherapy pathological examination of the resected specimen. How does this finding correlate with prognosis?
. It indicates a poor prognosis due to rapid tumor turnover.
. It is a strong positive prognostic factor, associated with improved survival.
. It has no significant correlation with overall prognosis.
. It suggests a high likelihood of distant metastatic recurrence.
. It primarily impacts the choice of adjuvant radiation therapy.

Correct Answer & Explanation

. It is a strong positive prognostic factor, associated with improved survival.

Explanation

For osteosarcoma, the degree of tumor necrosis after neoadjuvant chemotherapy is a critical prognostic factor. Patients who achieve >90% tumor necrosis (a 'good responder') have significantly better long-term survival rates compared to those with <90% necrosis ('poor responders'). This robust pathological response indicates the efficacy of systemic treatment against micrometastatic disease and is strongly associated with improved prognosis. It does not indicate poor prognosis or high likelihood of distant recurrence; quite the opposite.

Question 3947

Topic: 10. Pathology and Oncology

In the UICC staging of giant cell tumor of bone (GCTB), what is the significance of pulmonary metastases?

. They automatically classify the GCTB as malignant (sarcoma).
. They signify a poor prognosis, similar to other aggressive sarcomas.
. They are considered rare and usually associated with very aggressive primary tumors.
. They are classified as M1 disease but often have a relatively indolent course, sometimes amenable to surgery.
. They are not included in the UICC staging for GCTB, as GCTB is considered benign.

Correct Answer & Explanation

. They are classified as M1 disease but often have a relatively indolent course, sometimes amenable to surgery.

Explanation

Giant cell tumor of bone (GCTB) is an unusual bone tumor that, while histologically benign, has local aggressive potential and a small but definite risk of pulmonary metastases (3-5%). These pulmonary metastases, even though classified as M1 disease, often have a more indolent course than metastases from conventional high-grade sarcomas. They are often multiple, small, and can remain stable for long periods. They are amenable to surgical resection in many cases, and their presence does not necessarily imply a rapidly fatal outcome or malignant transformation, though they do indicate a more aggressive biological behavior than localized GCTB. They are indeed included in the UICC staging (M1).

Question 3948

Topic: 10. Pathology and Oncology

Which of the following describes the preferred surgical approach for a low-grade (G1) appendicular chondrosarcoma with an intact cortical shell and no extra-osseous extension?

. Intralesional curettage
. Marginal excision
. Wide en bloc resection
. Amputation
. Radiation therapy alone

Correct Answer & Explanation

. Marginal excision

Explanation

For low-grade (G1) chondrosarcomas that are intra-osseous and do not have significant cortical destruction or soft tissue extension, a marginal excision is often considered appropriate. This involves removing the tumor with a narrow margin of normal tissue surrounding it. While intralesional curettage can be considered for very low-grade, well-contained lesions in specific anatomical sites, marginal excision offers better local control for G1 chondrosarcomas. Wide en bloc resection is generally reserved for higher-grade lesions or those with extra-osseous extension. Amputation is typically for extensive, unresectable, or recurrent disease.

Question 3949

Topic: 10. Pathology and Oncology

A 15-year-old female with a known osteosarcoma of the distal femur undergoes a chest CT as part of her staging workup. The CT reveals a 3 mm indeterminate pulmonary nodule. What is the most appropriate next step in management?

. Proceed with neoadjuvant chemotherapy as planned and re-evaluate the nodule after treatment.
. Perform an immediate biopsy of the pulmonary nodule.
. Discontinue neoadjuvant chemotherapy and initiate palliative care.
. Repeat chest CT in 3 months to monitor the nodule's growth.
. Perform a PET-CT to further characterize the nodule.

Correct Answer & Explanation

. Proceed with neoadjuvant chemotherapy as planned and re-evaluate the nodule after treatment.

Explanation

Small, indeterminate pulmonary nodules (especially <5 mm) are common, and many are benign. For osteosarcoma, neoadjuvant chemotherapy is a critical part of the treatment regimen. It is standard practice to proceed with chemotherapy as planned. The nodules are then re-evaluated after chemotherapy; many will either disappear, remain stable (suggesting benignity), or grow (suggesting malignancy and requiring further intervention like resection). Immediate biopsy of such small nodules is often non-diagnostic and carries risks. Discontinuing chemotherapy and starting palliative care would be premature and inappropriate. Monitoring with repeat CT is often done, but typically after the initial chemotherapy phase for osteosarcoma, as the primary goal is to treat the known disease effectively.

Question 3950

Topic: 10. Pathology and Oncology

Which feature of a soft tissue mass on MRI is most indicative of malignancy and would warrant immediate biopsy?

. Homogeneous signal intensity
. Well-defined capsule
. Infiltration into adjacent structures
. Absence of contrast enhancement
. Location in the subcutaneous fat

Correct Answer & Explanation

. Infiltration into adjacent structures

Explanation

Infiltration into adjacent structures (muscle, fascia, neurovascular bundles, or bone) is a strong indicator of malignancy in a soft tissue mass. Malignant tumors tend to have infiltrative growth patterns. Homogeneous signal intensity and a well-defined capsule are more characteristic of benign lesions. Malignant tumors typically show heterogeneous signal intensity and often lack a well-defined capsule. Absence of contrast enhancement is usually seen in benign lesions (e.g., simple cysts, some lipomas), whereas most malignant soft tissue tumors enhance. While subcutaneous fat location can harbor sarcomas, deep-seated lesions are generally at higher risk of malignancy, and location alone isn't as indicative as infiltrative growth.

Question 3951

Topic: 10. Pathology and Oncology

What is the primary reason why 'Frozen Section Biopsy' is generally discouraged as the definitive diagnostic tool for suspected soft tissue or bone sarcomas?

. It requires specialized equipment not available in most hospitals.
. It has a high false-negative rate for low-grade tumors.
. Accurate grading and subtyping, crucial for planning, are often not possible.
. It significantly increases the risk of tumor dissemination.
. It is more painful for the patient than needle biopsy.

Correct Answer & Explanation

. Accurate grading and subtyping, crucial for planning, are often not possible.

Explanation

Frozen section biopsy is primarily used for rapid intraoperative assessment (e.g., checking margins), but it is generally insufficient for the definitive diagnosis of sarcomas. The complexity and heterogeneity of sarcomas mean that accurate grading and subtyping, which are crucial for treatment planning (e.g., choice of chemotherapy, surgical approach), often require extensive immunohistochemical staining and sometimes molecular studies that cannot be performed on frozen sections. A high false-negative rate for low-grade tumors is a concern, but the main issue is the inability to get precise characterization. It doesn't inherently increase dissemination risk more than other biopsies if performed correctly, and pain levels are comparable to other surgical biopsies.

Question 3952

Topic: 10. Pathology and Oncology

A 5-year-old child presents with a femoral shaft lesion and constitutional symptoms. Biopsy confirms Ewing sarcoma. What is the most common site of distant metastasis at presentation for Ewing sarcoma?

. Brain
. Liver
. Lymph nodes
. Lungs and other bones
. Kidneys

Correct Answer & Explanation

. Lungs and other bones

Explanation

Ewing sarcoma is highly aggressive and commonly presents with metastatic disease. The most common sites of distant metastasis at presentation are the lungs (pulmonary metastases) and other bones (skeletal metastases). Bone marrow involvement is also frequent. While other sites can be involved, lungs and other bones are the predominant sites. Lymph node involvement is less common than for carcinomas but can occur. Brain, liver, and kidneys are less frequent primary metastatic sites at presentation.

Question 3953

Topic: Bone Tumors

A 30-year-old patient undergoes surgical resection of a low-grade chondrosarcoma from the proximal humerus. The surgeon achieves an intralesional margin due to anatomical constraints (proximity to glenoid and neurovascular structures) but meticulously burrs the cavity and uses adjuvant cryotherapy. What is the most significant risk associated with this approach for a chondrosarcoma?

. Increased risk of pathological fracture
. High rate of distant metastasis
. Significant increase in local recurrence
. Development of post-operative infection
. Compromised shoulder function

Correct Answer & Explanation

. Significant increase in local recurrence

Explanation

Chondrosarcomas, even low-grade ones, are known for their potential for local recurrence, especially after intralesional or marginal resections. Chondrosarcoma cells can be left behind within the pseudo-capsule or surrounding tissues with intralesional approaches. While adjuvant treatments like burring and cryotherapy aim to reduce this risk, an intralesional margin inherently carries a significantly higher risk of local recurrence compared to marginal or wide excisions. Pathological fracture, distant metastasis (for low-grade, this risk is low), infection, and functional compromise are potential complications of any surgery but not themost significantrisk specific to an intralesional approach for chondrosarcoma. Local recurrence is the primary concern for oncologic outcome.

Question 3954

Topic: 10. Pathology and Oncology

In the context of the 8th edition UICC staging for soft tissue sarcomas, which characteristic automatically upgrades the T-stage to T4, irrespective of tumor size?

. Tumor depth (superficial vs. deep)
. Tumor location (trunk vs. extremity)
. Invasion of major neurovascular structures
. High histological grade (G3)
. Presence of regional lymph node metastases

Correct Answer & Explanation

. Invasion of major neurovascular structures

Explanation

For soft tissue sarcomas of the trunk and extremities (8th edition UICC), T4 is defined as a tumor of any size that invades a major neurovascular structure, bone, joint, or visceral organs. This is a critical distinction that reflects the increased complexity and morbidity of resection, and often poorer prognosis. Tumor depth (superficial vs. deep) used to be a T-stage modifier but is now primarily a prognostic factor. Tumor location doesn't change the T-stage definition but might influence overall prognosis. High histological grade is the G-stage. Regional lymph node metastases are part of the N-stage.

Question 3955

Topic: 10. Pathology and Oncology

Which of the following bone tumors is characteristically pain-responsive to NSAIDs and often appears as a small, lucent nidus with surrounding dense sclerosis on X-ray?

. Osteosarcoma
. Ewing sarcoma
. Osteoid osteoma
. Enchondroma
. Non-ossifying fibroma

Correct Answer & Explanation

. Osteoid osteoma

Explanation

Osteoid osteoma is a benign bone-forming tumor characterized by nocturnal pain that is classically relieved by NSAIDs (like aspirin). Radiographically, it presents as a small lucent nidus (typically <1.5-2 cm) surrounded by a zone of reactive sclerosis. This classic presentation makes it distinct from the other options, which either do not have this pain response (Enchondroma, Non-ossifying fibroma) or have very different radiographic appearances and clinical presentations (Osteosarcoma, Ewing Sarcoma).

Question 3956

Topic: 10. Pathology and Oncology

A 60-year-old male presents with a painful mass in his sacrum. Biopsy reveals chordoma. What is the most common site of distant metastasis for chordoma?

. Lung
. Liver
. Brain
. Regional lymph nodes
. Bone

Correct Answer & Explanation

. Lung

Explanation

Chordoma is a rare, slow-growing, malignant bone tumor derived from notochordal remnants, most commonly found in the sacrococcygeal region and skull base. While it is characterized by local aggressiveness and high rates of local recurrence, distant metastases do occur, with the lung being the most common site. Bone and soft tissue metastases also occur but are less frequent than lung metastases. Liver and brain metastases are relatively rare.

Question 3957

Topic: 10. Pathology and Oncology
Which of the following pathological findings is most suggestive of an aggressive, high-grade soft tissue sarcoma?
. Scattered mitotic figures, no necrosis
. Uniform cells, bland nuclei, minimal pleomorphism
. Extensive cellular pleomorphism, numerous atypical mitotic figures, geographic necrosis
. Presence of fatty differentiation, well-defined septae
. Sclerotic stroma, low cellularity

Correct Answer & Explanation

. Extensive cellular pleomorphism, numerous atypical mitotic figures, geographic necrosis

Explanation

The combination of extensive cellular pleomorphism (variation in cell size and shape), numerous atypical mitotic figures (indicating rapid and uncontrolled cell division), and geographic necrosis (areas of dead tumor cells, often extensive) are hallmark features of high-grade, aggressive soft tissue sarcomas. These features are key components in grading systems like FNCLCC. The other options describe features more typical of low-grade sarcomas or benign lesions.

Question 3958

Topic: 10. Pathology and Oncology

For a patient diagnosed with a Stage IIB (UICC 8th ed.) osteosarcoma of the proximal tibia, which M-stage (metastasis) is implicitly assumed?

. M0
. M1a
. M1b
. Mx
. M0 and M1a

Correct Answer & Explanation

. M0

Explanation

In the 8th edition UICC staging for bone sarcomas, Stage IIB refers to a high-grade (G3 or G2 if applicable by context, typically G3 for osteosarcoma) tumor with T2 (tumor >8 cm) or T3 (skip lesions) butwithoutany regional lymph node involvement (N0) or distant metastasis (M0). The presence of any metastasis (M1) would automatically upgrade the stage to Stage IV. Therefore, for Stage IIB, M0 is implicitly assumed.

Question 3959

Topic: 10. Pathology and Oncology

A 12-year-old male with a distal femoral Ewing sarcoma undergoes neoadjuvant chemotherapy. After 3 cycles, MRI shows significant tumor shrinkage and sclerotic changes within the tumor. What is the most appropriate interpretation of these imaging findings?

. The tumor is progressing despite chemotherapy.
. The patient is a poor responder to chemotherapy, requiring a change in regimen.
. These findings are suggestive of a good response to chemotherapy.
. The tumor is likely benign and does not require further treatment.
. The patient should proceed directly to amputation.

Correct Answer & Explanation

. These findings are suggestive of a good response to chemotherapy.

Explanation

Significant tumor shrinkage (reduction in size) and sclerotic changes (increased bone density) within a bone sarcoma after neoadjuvant chemotherapy are strong indicators of a good response to treatment. These changes represent tumor cell kill and replacement by osteoid/fibrotic tissue. This often correlates with a good pathological response (high percentage of necrosis). Tumor progression would involve growth or new lesions. A poor response would show minimal change or continued growth. Proceeding directly to amputation or assuming benignity would be incorrect based on these positive findings.

Question 3960

Topic: 10. Pathology and Oncology

Which of the following is considered the primary role of a positron emission tomography (PET) scan in the staging of musculoskeletal sarcomas?

. Assessing local tumor extent and invasion of neurovascular structures.
. Identifying skip lesions within the primary bone.
. Detecting distant metastases and occult disease, particularly in lymph nodes or bone.
. Evaluating tumor response to neoadjuvant chemotherapy.
. Differentiating between benign and malignant bone lesions.

Correct Answer & Explanation

. Detecting distant metastases and occult disease, particularly in lymph nodes or bone.

Explanation

The primary role of PET-CT in the staging of musculoskeletal sarcomas is to detect distant metastases and occult disease, particularly in regional lymph nodes or other bones, and sometimes in lung/liver, especially when conventional imaging is equivocal. Sarcomas are often metabolically active, making PET-CT sensitive for metastatic disease. MRI is superior for local extent and neurovascular involvement. Skip lesions are primarily detected by MRI. While PET-CT can sometimes help evaluate response, pathological necrosis is the gold standard. Differentiating benign from malignant is primarily done by biopsy, though PET can aid in identifying suspicious lesions.

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