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10. Pathology and Oncology MCQs

Practice Set 47 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 921

Topic: 10. Pathology and Oncology
A 45-year-old female undergoes a biopsy of a posterior distal femoral surface lesion, which returns as a low-grade parosteal osteosarcoma. Imaging demonstrates that the tumor is entirely confined within the fascia of the posterior thigh compartment without marrow invasion or distant metastasis. What is the Enneking surgical stage?
. IA
. IB
. IIA
. IIB
. III

Correct Answer & Explanation

. IA

Explanation

The tumor is low grade (G1) and intracompartmental (T1) without metastasis (M0), classifying it as Enneking Stage IA. Stage IB would involve extracompartmental extension beyond the native compartment.

Question 922

Topic: 10. Pathology and Oncology
A 15-year-old girl is diagnosed with a conventional high-grade osteosarcoma of the proximal humerus. MRI confirms the tumor remains completely contained within the medullary canal and cortex, with no soft tissue mass or distant metastasis. What is her Enneking stage?
. IA
. IB
. IIA
. IIB
. III

Correct Answer & Explanation

. IIA

Explanation

A high-grade (G2), intracompartmental (T1) tumor with no metastases (M0) is classified as Enneking Stage IIA. Once it breaches the cortex into the soft tissue, it becomes Stage IIB.

Question 923

Topic: 10. Pathology and Oncology

A 14-year-old boy has an incidental finding of an eccentric, cortically based, well-circumscribed sclerotic-margined radiolucent lesion in the distal tibia. It is asymptomatic and biopsy confirms a non-ossifying fibroma. What is the Enneking stage for this benign lesion?

. Stage 1
. Stage 2
. Stage 3
. Stage IA
. Stage IB

Correct Answer & Explanation

. Stage 1

Explanation

Enneking Stage 1 describes a latent benign tumor that is static or healing, well-marginated, and asymptomatic, such as a typical non-ossifying fibroma. Stage 2 lesions are actively growing but remain contained.

Question 924

Topic: 10. Pathology and Oncology

In the Enneking staging system for musculoskeletal tumors, which of the following events automatically changes a tumor from intracompartmental (T1) to extracompartmental (T2)?

. Invasion into the medullary canal
. Extension from the metaphysis into the epiphysis
. Intra-articular extension into the joint space
. Expansion causing endosteal scalloping
. Invasion of the cancellous bone

Correct Answer & Explanation

. Intra-articular extension into the joint space

Explanation

Joints are considered extracompartmental spaces in the Enneking staging system. Therefore, intra-articular extension upgrades the local anatomy from T1 to T2.

Question 925

Topic: 10. Pathology and Oncology
A 62-year-old man presents with groin pain. Imaging reveals a large, destructive lesion of the ilium with a massive associated soft tissue mass extending into the gluteal musculature. Biopsy confirms a grade 3 dedifferentiated chondrosarcoma. Staging CTs are negative for metastasis. What is the Enneking stage?
. IB
. IIA
. IIB
. III
. IV

Correct Answer & Explanation

. IIB

Explanation

This is a high-grade tumor (G2) with extracompartmental extension (T2) and no metastases (M0), classifying it as Enneking Stage IIB. Dedifferentiated chondrosarcomas are universally high grade.

Question 926

Topic: 10. Pathology and Oncology

A surgeon performs a resection of a soft tissue sarcoma. Pathology analysis reveals that the resection plane passed entirely through the pseudocapsule and the surrounding reactive tissue, but did not cut directly into the gross tumor. According to Enneking's surgical margins, how is this resection classified?

. Intralesional
. Marginal
. Wide
. Radical
. Contaminated

Correct Answer & Explanation

. Marginal

Explanation

A marginal excision involves a dissection plane through the pseudocapsule or reactive zone, which may contain microscopic satellite lesions. A wide margin requires a continuous cuff of normal tissue in all directions.

Question 927

Topic: 10. Pathology and Oncology

A 30-year-old female is diagnosed with an Enneking Stage 3 benign giant cell tumor of the proximal tibia with an extensive soft-tissue component. She is treated with neoadjuvant denosumab. What is the primary surgical goal of this neoadjuvant therapy prior to definitive joint-preserving resection?

. To induce malignant transformation to a resectable low-grade sarcoma
. To eradicate microscopic pulmonary metastases
. To stimulate endosteal scalloping
. To allow for intralesional curettage by shrinking the soft tissue mass and ossifying the margins
. To increase tumor vascularity to aid in surgical dissection

Correct Answer & Explanation

. To allow for intralesional curettage by shrinking the soft tissue mass and ossifying the margins

Explanation

Denosumab inhibits RANKL, leading to tumor consolidation and a peripheral rim of ossification. This facilitates joint-preserving intralesional extended curettage for aggressive Stage 3 GCTs that might otherwise require en bloc resection.

Question 928

Topic: 10. Pathology and Oncology
A 25-year-old male has an indolent, low-grade adamantinoma of the tibial diaphysis. Imaging shows the tumor has broken through the anterior cortex and involves the anterior compartment musculature. No metastases are identified. What is the Enneking stage?
. IA
. IB
. IIA
. IIB
. III

Correct Answer & Explanation

. IB

Explanation

The tumor is low grade (G1) with extracompartmental extension (T2) into the anterior compartment muscles, and no metastases (M0), making it Enneking Stage IB. Adamantinomas are typically low-grade malignant bone tumors.

Question 929

Topic: 10. Pathology and Oncology

What is the minimum recommended oncologic surgical margin to achieve local control with the lowest risk of recurrence for an Enneking Stage IIB osteosarcoma after appropriate neoadjuvant chemotherapy?

. Intralesional
. Marginal
. Wide
. Radical
. Amputation

Correct Answer & Explanation

. Wide

Explanation

A wide surgical margin, which encompasses the tumor along with a continuous cuff of normal tissue, is the standard of care for high-grade sarcomas (Stage IIA/IIB). Radical margins are rarely required today due to the efficacy of modern chemotherapy.

Question 930

Topic: 10. Pathology and Oncology

A 19-year-old male presents with persistent thoracic spine pain not relieved by NSAIDs. Imaging reveals a 2.5 cm expansile, radiolucent lesion in the T8 posterior elements with a thin rim of surrounding reactive sclerosis. The cortex is thinned but intact. Biopsy shows an osteoblastoma. What is the Enneking benign stage?

. Stage 1
. Stage 2
. Stage 3
. Stage IA
. Stage IB

Correct Answer & Explanation

. Stage 2

Explanation

Enneking Stage 2 describes active benign tumors that grow progressively and expand the bone but remain contained within a thin cortical shell or periosteal margin. Osteoblastomas typically fit this profile.

Question 931

Topic: 10. Pathology and Oncology
A 50-year-old woman is diagnosed with a high-grade pleomorphic sarcoma of the quadriceps. Preoperative staging reveals no lung metastases, but a biopsy of an enlarged inguinal lymph node confirms the presence of sarcoma cells. According to the Enneking musculoskeletal staging system, what is her stage?
. IIA
. IIB
. III
. IV
. V

Correct Answer & Explanation

. III

Explanation

In the Enneking staging system, any metastasis, whether regional (lymph node) or distant (pulmonary), automatically classifies the tumor as Stage III. This is distinct from other staging systems like the AJCC.

Question 932

Topic: 10. Pathology and Oncology

According to the Enneking principles of oncologic resection, which of the following best describes a "radical" surgical margin?

. Removal of the tumor with a 2-cm cuff of normal tissue in all planes
. Removal of the entire longitudinal anatomic compartment containing the tumor
. Excision through the pseudocapsule and reactive zone
. Amputation proximal to the tumor through the involved bone
. Excision of the tumor with an intact fascial plane on only one aspect

Correct Answer & Explanation

. Removal of the entire longitudinal anatomic compartment containing the tumor

Explanation

A radical margin involves the en bloc removal of the tumor along with the entire anatomic compartment(s) from origin to insertion. A wide margin only requires a cuff of normal tissue.

Question 933

Topic: 10. Pathology and Oncology

When comparing the Enneking surgical staging system to the American Joint Committee on Cancer (AJCC) staging system for bone sarcomas, which of the following variables is included in the AJCC system but explicitly excluded from the Enneking system?

. Histologic grade
. Presence of distant metastasis
. Presence of regional lymph node metastasis
. Anatomic compartmentalization
. Tumor size

Correct Answer & Explanation

. Tumor size

Explanation

The AJCC staging system for bone sarcomas incorporates tumor size (e.g., >8 cm) as a key staging variable. The Enneking system focuses purely on histologic grade, compartmental boundaries, and metastasis.

Question 934

Topic: 10. Pathology and Oncology
A 12-year-old girl is diagnosed with Ewing sarcoma of the diaphyseal femur. Imaging shows a large soft tissue mass breaking through the cortex. A staging bone marrow biopsy is positive for isolated clusters of Ewing sarcoma cells, though chest CT is clear. What is her Enneking stage?
. IIA
. IIB
. III
. IIIA
. IV

Correct Answer & Explanation

. III

Explanation

The presence of tumor cells in the bone marrow distant from the primary site constitutes metastasis (M1). In the Enneking system, any metastasis automatically makes it a Stage III tumor.

Question 935

Topic: 10. Pathology and Oncology

In the context of Enneking staging, which of the following anatomic structures is considered an intracompartmental space rather than an extracompartmental space?

. Popliteal fossa
. Femoral triangle
. Anterior compartment of the thigh
. Axilla
. Subcutaneous fat

Correct Answer & Explanation

. Anterior compartment of the thigh

Explanation

The anterior compartment of the thigh is bounded by fascial septa and bone, making it a true anatomic intracompartmental space. The popliteal fossa, femoral triangle, axilla, and subcutaneous fat lack complete fascial boundaries and are extracompartmental.

Question 936

Topic: 10. Pathology and Oncology

A 35-year-old asymptomatic male is found to have an Enneking Stage 1 benign enchondroma in his proximal humerus on radiographs taken after a minor shoulder sprain. What is the most appropriate management?

. Extended intralesional curettage with phenol
. Wide en bloc resection
. Observation with serial radiographs
. Prophylactic internal fixation
. Neoadjuvant chemotherapy followed by marginal excision

Correct Answer & Explanation

. Observation with serial radiographs

Explanation

Enneking Stage 1 benign tumors are latent, asymptomatic, and carry a very low risk of progression. Observation with serial radiographs is the standard of care.

Question 937

Topic: 10. Pathology and Oncology
A 16-year-old male with a high-grade osteosarcoma of the distal femur undergoes staging MRI. A second, discrete focus of osteosarcoma is found within the proximal medullary canal of the same femur, separated from the primary tumor by normal marrow. How does this finding affect the Enneking stage?
. It changes the local stage from T1 to T2
. It is considered a skip metastasis, automatically upgrading the tumor to Stage III
. It downgrades the required surgical margin to marginal
. It has no effect on the Enneking stage as it is in the same compartment
. It changes the histologic grade from G1 to G2

Correct Answer & Explanation

. It is considered a skip metastasis, automatically upgrading the tumor to Stage III

Explanation

In the Enneking staging system, a skip metastasis within the same bone or adjacent compartment is classified as regional metastasis (M1). This upgrades the tumor to Stage III and portends a poorer prognosis.

Question 938

Topic: 10. Pathology and Oncology
A 42-year-old female is diagnosed with a grade 1 chondrosarcoma originating in the medullary canal of the proximal femur. MRI demonstrates that the tumor has extensively thinned the cortex and caused endosteal scalloping, but the cortex remains intact without soft tissue extension. What is the Enneking stage?
. IA
. IB
. IIA
. IIB
. III

Correct Answer & Explanation

. IA

Explanation

The tumor is low grade (G1) and remains confined within the osseous compartment (T1), with no metastases (M0). Cortical thinning without breakthrough remains an intracompartmental lesion, making it Stage IA.

Question 939

Topic: 10. Pathology and Oncology
A 15-year-old girl presents with a rapidly enlarging distal femur mass. Biopsy reveals conventional osteosarcoma. MRI shows the tumor filling the medullary canal and breaking through the posterior cortex into the vastus intermedius, but not crossing the joint line. Chest CT and bone scan are negative for metastases. What is the Enneking surgical stage of this tumor?
. Stage IA
. Stage IB
. Stage IIA
. Stage IIB
. Stage III

Correct Answer & Explanation

. Stage IIB

Explanation

This is a high-grade tumor (G2), which is extracompartmental (T2) due to cortical breach into the muscle, with no metastases (M0). According to the Enneking staging system, G2, T2, M0 is classified as Stage IIB.

Question 940

Topic: 10. Pathology and Oncology

Which of the following anatomic locations is classified as an inherently extracompartmental space in the Enneking staging system?

. Medullary canal of the femur
. Anterior compartment of the thigh
. Popliteal fossa
. Posterior compartment of the leg
. Deltoid muscle

Correct Answer & Explanation

. Popliteal fossa

Explanation

Extracompartmental spaces lack robust fascial boundaries and natively include the popliteal fossa, axilla, femoral triangle, and paraspinal spaces. Primary tumors arising in these regions are automatically classified as T2.

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