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10. Pathology and Oncology MCQs

Practice Set 170 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 3381

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain and a palpable mass in the distal femur. Radiographs reveal a mixed lytic and sclerotic lesion with a 'sunburst' periosteal reaction. Core needle biopsy confirms high-grade, conventional osteosarcoma. What is the standard initial management?

. Immediate above-knee amputation
. Primary wide surgical excision followed by radiation
. Neoadjuvant chemotherapy
. Definitive radiation therapy
. Intralesional curettage and bone grafting

Correct Answer & Explanation

. Neoadjuvant chemotherapy

Explanation

The standard of care for high-grade conventional osteosarcoma is neoadjuvant chemotherapy, followed by wide surgical resection, and then adjuvant chemotherapy. The histological response to initial chemotherapy is a major prognostic factor.

Question 3382

Topic: 10. Pathology and Oncology

A 10-year-old girl is diagnosed with Ewing sarcoma of the diaphysis of the humerus. Which specific chromosomal translocation is most classically associated with this malignancy?

. t(X;18)
. t(9;22)
. t(11;22)
. t(12;16)
. t(2;13)

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is driven by a characteristic fusion of the EWS gene with the FLI1 gene. This is caused by the t(11;22)(q24;q12) chromosomal translocation in approximately 85% of cases.

Question 3383

Topic: 10. Pathology and Oncology

A 65-year-old man presents with a destructive lesion in the proximal humerus. Biopsy confirms metastatic clear cell renal cell carcinoma. He is scheduled for wide resection and endoprosthetic reconstruction. What is the most critical pre-operative step?

. Pre-operative radiation therapy
. Neoadjuvant chemotherapy
. Pre-operative arterial embolization
. Intralesional steroid injection
. Bone marrow aspiration

Correct Answer & Explanation

. Pre-operative arterial embolization

Explanation

Metastatic renal cell carcinoma lesions are highly vascular and prone to massive intraoperative hemorrhage. Pre-operative selective arterial embolization, typically 24-48 hours before surgery, significantly reduces surgical blood loss.

Question 3384

Topic: 10. Pathology and Oncology
A 55-year-old man presents with dull pain in the proximal femur. Radiographs show a lytic lesion with 'rings and arcs' calcification. MRI reveals endosteal scalloping involving >2/3 of the cortical thickness. Biopsy confirms grade II chondrosarcoma. What is the primary modality of treatment?
. Definitive radiation therapy
. Neoadjuvant chemotherapy followed by curettage
. Wide surgical resection
. Intralesional curettage with liquid nitrogen cryotherapy
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

Intermediate and high-grade chondrosarcomas (Grades II and III) are largely resistant to both chemotherapy and radiation. Wide surgical resection with negative margins is the definitive standard of care.

Question 3385

Topic: 10. Pathology and Oncology

A 14-year-old boy has a high-grade intramedullary osteosarcoma of the distal femur. Following neoadjuvant chemotherapy and wide resection, what histological finding in the resected specimen is the most important prognostic factor for overall survival?

. Percentage of tumor necrosis
. Tumor volume
. Presence of chondroblastic differentiation
. Number of mitotic figures per high-power field
. Width of the surgical margin

Correct Answer & Explanation

. Percentage of tumor necrosis

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy (Huvos grading system) is the most significant prognostic factor in osteosarcoma. Greater than 90% necrosis indicates a good response and correlates with better overall survival.

Question 3386

Topic: 10. Pathology and Oncology

A 10-year-old boy presents with a diaphyseal lytic lesion of the fibula with an "onion-skin" periosteal reaction. Biopsy shows uniform small blue round cells. Which chromosomal translocation is most characteristic of this tumor?

. t(11;22)(q24;q12)
. t(9;22)(q34;q11)
. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)

Correct Answer & Explanation

. t(11;22)(q24;q12)

Explanation

Ewing sarcoma is classically characterized by the t(11;22)(q24;q12) translocation, which results in the EWS-FLI1 fusion protein. This molecular marker is used to confirm the diagnosis.

Question 3387

Topic: 10. Pathology and Oncology
A 55-year-old man is found to have a 6 cm calcified intramedullary lesion in his proximal humerus with endosteal scalloping. Biopsy confirms grade II (intermediate-grade) chondrosarcoma. What is the most appropriate definitive management?
. Neoadjuvant chemotherapy followed by wide resection
. Intralesional curettage and bone grafting
. Wide surgical resection alone
. Primary radiation therapy
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas (especially grade II and III) are notably resistant to both chemotherapy and radiotherapy. The standard of care is wide surgical resection with negative margins.

Question 3388

Topic: Bone Tumors

A 65-year-old man presents with severe back pain and a solitary lytic lesion in the L3 vertebral body. Laboratory testing reveals an M spike on serum protein electrophoresis. What imaging modality is considered the standard of care for staging skeletal involvement in this disease?

. Technetium-99m bone scan
. Whole-body low-dose CT or PET-CT
. Ultrasound of the abdomen
. Gadolinium-enhanced MRI of the brain
. Plain radiography limited to symptomatic areas

Correct Answer & Explanation

. Whole-body low-dose CT or PET-CT

Explanation

Whole-body low-dose CT or PET-CT is the standard imaging modality for the skeletal survey in multiple myeloma. Technetium-99m bone scans are often false-negative because myeloma lesions are purely lytic and lack the osteoblastic activity required for tracer uptake.

Question 3389

Topic: Bone Tumors

A 19-year-old male complains of severe, progressively worsening right thigh pain that occurs primarily at night and is dramatically relieved by NSAIDs. Imaging shows a radiolucent nidus surrounded by dense reactive sclerosis. What is the most definitive, minimally invasive treatment?

. Wide en bloc resection
. Chemotherapy followed by local resection
. Radiofrequency ablation (RFA)
. Extended curettage with phenol adjuvant
. Intravenous bisphosphonates

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. CT-guided radiofrequency ablation (RFA) is the definitive, minimally invasive standard of care, offering excellent success rates and minimal morbidity compared to open surgery.

Question 3390

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful diaphyseal mass in his right femur, low-grade fever, and an elevated erythrocyte sedimentation rate (ESR). Biopsy reveals sheets of uniform small round blue cells. Cytogenetic analysis of this tumor is most likely to demonstrate which of the following translocations?

. t(9;22)
. t(X;18)
. t(11;22)
. t(2;13)
. t(12;16)

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and histologic findings are diagnostic of Ewing sarcoma. The classic chromosomal translocation associated with Ewing sarcoma is t(11;22), which results in the EWS-FLI1 fusion protein.

Question 3391

Topic: 10. Pathology and Oncology

In the multimodal management of high-grade, conventional intramedullary osteosarcoma of the distal femur, which of the following is considered the most critical prognostic factor for long-term patient survival?

. Tumor size at the time of presentation
. Type of limb-salvage reconstruction performed
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Patient's chronologic age at diagnosis
. Preoperative serum alkaline phosphatase levels

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The histologic response to neoadjuvant chemotherapy, specifically greater than 90% tumor necrosis, is the single most important prognostic factor for overall survival in osteosarcoma. Poor responders have a significantly higher risk of metastasis and mortality.

Question 3392

Topic: 10. Pathology and Oncology
A 60-year-old man presents with dull pain in his proximal humerus. Radiographs reveal a large lytic lesion with intralesional "popcorn" calcifications and endosteal scalloping >2/3 of the cortical thickness. Biopsy confirms grade II chondrosarcoma. What is the most appropriate definitive treatment?
. Intralesional curettage and bone grafting
. Intralesional curettage with polymethylmethacrylate cementation
. Neoadjuvant chemotherapy followed by wide resection
. Wide surgical resection alone
. Definitive external beam radiation therapy

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas (especially grade II and III) are highly resistant to both chemotherapy and radiation. The standard of care is wide surgical resection alone with negative margins.

Question 3393

Topic: Bone Tumors

An 18-year-old male presents with painful scoliosis. Imaging reveals a 2.5 cm radiolucent lesion with a mineralized matrix in the posterior elements of L3. The pain is persistent and is only partially relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). What is the most likely diagnosis?

. Osteoid osteoma
. Osteoblastoma
. Aneurysmal bone cyst
. Giant cell tumor
. Chondroblastoma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Osteoblastomas are histologically similar to osteoid osteomas but are distinguished by being larger (>1.5-2.0 cm), exhibiting progressive growth, and causing pain that is less responsive to NSAIDs. They commonly occur in the posterior elements of the spine.

Question 3394

Topic: Bone Tumors

A 65-year-old man presents with new-onset back pain, anemia, and an M-spike on serum protein electrophoresis. Radiographs show a compression fracture of T12 and punched-out lytic skull lesions. Which of the following imaging modalities is most sensitive for detecting additional early osseous lesions in this patient?

. Technetium-99m bone scan
. Skeletal survey radiographs
. Whole-body MRI
. Dual-energy X-ray absorptiometry (DEXA) scan
. Diagnostic skeletal ultrasound

Correct Answer & Explanation

. Whole-body MRI

Explanation

Whole-body MRI (or PET-CT) is highly sensitive for detecting bone marrow involvement in multiple myeloma. Technetium-99m bone scans are notoriously insensitive because myeloma lesions are purely osteolytic and lack the osteoblastic response needed for tracer uptake.

Question 3395

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a painful mass in his distal femur. Radiographs show a "sunburst" periosteal reaction. He has a history of bilateral enucleation as an infant. Which mutated gene is most directly implicated in both of his neoplastic conditions?

. TP53
. RB1
. EXT1
. APC
. NF1

Correct Answer & Explanation

. RB1

Explanation

The patient has a history of bilateral retinoblastoma, which is strongly associated with mutations in the RB1 tumor suppressor gene. This mutation significantly increases the lifetime risk of developing osteosarcoma.

Question 3396

Topic: 10. Pathology and Oncology

A 60-year-old man presents with dull, aching hip pain. Radiographs show a lytic lesion in the proximal femur with endosteal scalloping and "rings and arcs" calcification. Biopsy confirms a grade II chondrosarcoma. What is the mainstay of treatment?

. Neoadjuvant chemotherapy followed by wide resection
. Primary radiation therapy
. Wide surgical resection alone
. Intralesional curettage and bone grafting
. Denosumab therapy

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas are generally resistant to chemotherapy and radiation. The mainstay of treatment is wide surgical resection with negative margins.

Question 3397

Topic: 10. Pathology and Oncology

A 14-year-old girl presents with fever and localized pain in her mid-tibia. Radiographs show a permeative, diaphyseal lytic lesion with an "onion-skin" periosteal reaction. Histology reveals small round blue cells. Which of the following immunohistochemical markers and genetic translocations are characteristic of this tumor?

. CD99 positive; t(11;22)
. CD34 positive; t(X;18)
. S-100 positive; t(12;16)
. Vimentin positive; t(9;22)
. Cytokeratin positive; t(2;13)

Correct Answer & Explanation

. CD99 positive; t(11;22)

Explanation

Ewing sarcoma is a small round blue cell tumor typically positive for CD99 (MIC2). It is driven by the t(11;22) translocation resulting in the EWS-FLI1 fusion gene.

Question 3398

Topic: Bone Tumors

A 22-year-old male presents with dull, aching pain in his mid-back that is constant, night-predominant, and only partially relieved by ibuprofen. CT scan shows a 3.5 cm expansile lytic lesion in the posterior elements of T8 with a distinct radiolucent nidus and surrounding sclerosis. What is the most likely diagnosis?

. Osteoid osteoma
. Osteosarcoma
. Aneurysmal bone cyst
. Osteoblastoma
. Chondromyxoid fibroma

Correct Answer & Explanation

. Osteoblastoma

Explanation

While similar histologically to an osteoid osteoma, an osteoblastoma is larger (typically >2 cm), often found in the posterior elements of the spine, and has pain that is less consistently relieved by NSAIDs.

Question 3399

Topic: 10. Pathology and Oncology

A 14-year-old boy is diagnosed with high-grade osteosarcoma of the distal femur. Following neoadjuvant chemotherapy, what percentage of tumor necrosis is the threshold defining a 'good histological response' according to the Huvos grading system?

. 50%
. 75%
. 90%
. 95%
. 99%

Correct Answer & Explanation

. 90%

Explanation

A good histological response to neoadjuvant chemotherapy in osteosarcoma is defined as greater than 90% tumor necrosis. This is the single most significant prognostic factor for overall survival.

Question 3400

Topic: 10. Pathology and Oncology

A 9-year-old boy presents with a diaphyseal lesion of the fibula with an 'onion skin' periosteal reaction. A biopsy reveals small blue round cells. Which chromosomal translocation is most commonly associated with this malignancy?

. t(11;22)
. t(9;22)
. t(X;18)
. t(12;16)
. t(2;13)

Correct Answer & Explanation

. t(11;22)

Explanation

The presentation is classic for Ewing sarcoma, which is characterized by the t(11;22) translocation resulting in the EWS-FLI1 fusion protein. This anomaly is found in approximately 85-90% of Ewing sarcoma cases.

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