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10. Pathology and Oncology MCQs

Practice Set 287 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 5721

Topic: 10. Pathology and Oncology

In the Enneking staging system for benign musculoskeletal tumors, what defines a Stage 3 (aggressive) lesion?

. Latent lesion confined entirely within the capsule
. Active lesion expanding the cortex but remaining contained
. Symptomatic lesion that has breached the tumor capsule into reactive tissue
. Lesion with regional lymph node metastasis
. Lesion with distant pulmonary metastasis

Correct Answer & Explanation

. Symptomatic lesion that has breached the tumor capsule into reactive tissue

Explanation

A Stage 3 benign tumor is classified as locally aggressive in the Enneking system. It is characterized by progressive growth, rapid cortical destruction, and extension through the capsule into the surrounding reactive zone.

Question 5722

Topic: Bone Tumors

A 65-year-old male presents with a painful, destructive lytic lesion in his proximal humerus. Laboratory evaluation reveals hypercalcemia and an elevated total serum protein. Which test is most definitive for confirming the underlying diagnosis?

. Serum alkaline phosphatase level
. Serum protein electrophoresis (SPEP)
. Technetium-99m bone scintigraphy
. Prostate specific antigen (PSA)
. Erythrocyte sedimentation rate (ESR)

Correct Answer & Explanation

. Serum protein electrophoresis (SPEP)

Explanation

The clinical picture strongly suggests multiple myeloma, the most common primary bone malignancy in older adults. SPEP and UPEP are essential diagnostic tests to identify the characteristic monoclonal spike (M-protein) associated with this disease.

Question 5723

Topic: Bone Tumors

A 15-year-old boy presents with progressive knee pain. Radiographs reveal an ill-defined metaphyseal lytic lesion in the distal femur with periosteal elevation forming an acute angle with the cortex. What is this radiographic sign called, and what does it typically indicate?

. Onion skinning; Ewing sarcoma
. Fallen leaf sign; Unicameral bone cyst
. Codman triangle; Osteosarcoma
. Popcorn calcification; Chondrosarcoma
. Shepherd's crook deformity; Fibrous dysplasia

Correct Answer & Explanation

. Codman triangle; Osteosarcoma

Explanation

The Codman triangle is a pattern of periosteal reaction where the periosteum is rapidly lifted by an aggressive lesion, forming an angle with the underlying normal cortex. It is classically associated with highly aggressive primary bone tumors like osteosarcoma.

Question 5724

Topic: 10. Pathology and Oncology
In the management of high-grade appendicular osteosarcoma, histologic evaluation assesses tumor necrosis following neoadjuvant chemotherapy. According to the Huvos grading system, a "good response" predictive of improved survival is defined as:
. Greater than 50% tumor necrosis
. Greater than 75% tumor necrosis
. Greater than 90% tumor necrosis
. Greater than 99% tumor necrosis
. Complete absence of mitotic figures

Correct Answer & Explanation

. Greater than 90% tumor necrosis

Explanation

A "good response" to neoadjuvant chemotherapy in osteosarcoma is classically defined as greater than 90% tumor necrosis (Huvos Grade III or IV). This degree of necrosis is a strong independent predictor of overall disease-free survival.

Question 5725

Topic: 10. Pathology and Oncology

In a 15-year-old patient diagnosed with a high-grade intramedullary osteosarcoma of the distal femur, what is the most important prognostic factor for long-term overall survival?

. Tumor volume at initial presentation
. Specific histologic subtype (e.g., osteoblastic vs. chondroblastic)
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Initial serum alkaline phosphatase level
. Presence of a skip metastasis within the same bone

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for overall survival in patients with localized high-grade osteosarcoma. A 'good response' is typically defined as greater than 90% tumor necrosis upon histologic examination of the resected specimen.

Question 5726

Topic: Bone Tumors

A 70-year-old female presents with severe, atraumatic back pain. Radiographs reveal multiple 'punched-out' lytic lesions in the skull and a compression fracture of L2. Serum protein electrophoresis shows a monoclonal spike. Which of the following laboratory findings is also most characteristically associated with this patient's underlying disease?

. Elevated serum alkaline phosphatase
. Hypocalcemia
. Elevated Bence Jones proteins in the urine
. Decreased erythrocyte sedimentation rate (ESR)
. Negative Rouleaux formation on blood smear

Correct Answer & Explanation

. Elevated Bence Jones proteins in the urine

Explanation

The patient's presentation is highly characteristic of multiple myeloma, the most common primary malignancy of bone in adults. Characteristic laboratory findings include hypercalcemia (not hypocalcemia), normal alkaline phosphatase (unless there is a healing fracture), M-spike on SPEP, positive Rouleaux formation, and the presence of Bence Jones proteins (free light chains) in the urine.

Question 5727

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a permeative lytic lesion in the diaphysis of the femur with an 'onion skin' periosteal reaction. Biopsy reveals sheets of small, round, blue cells. Which of the following chromosomal translocations is most characteristic of this malignancy?

. t(X;18) (SYT-SSX)
. t(11;22) (EWSR1-FLI1)
. t(2;13) (PAX3-FOXO1)
. t(12;21) (ETV6-RUNX1)
. t(9;22) (BCR-ABL)

Correct Answer & Explanation

. t(11;22) (EWSR1-FLI1)

Explanation

The clinical and histological presentation describes Ewing sarcoma. The most common defining chromosomal translocation in Ewing sarcoma is t(11;22), which results in the EWSR1-FLI1 fusion protein (found in about 85% of cases). t(X;18) is seen in synovial sarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma.

Question 5728

Topic: 10. Pathology and Oncology

A 16-year-old male presents with distal femoral pain. Imaging reveals a mixed lytic/sclerotic lesion with a "sunburst" periosteal reaction. Biopsy confirms high-grade osteosarcoma. Which of the following laboratory markers, when elevated at presentation, serves as an independent negative prognostic indicator for survival?

. C-reactive protein (CRP)
. Serum calcium
. Serum alkaline phosphatase (ALP)
. Erythrocyte sedimentation rate (ESR)
. Serum parathyroid hormone (PTH)

Correct Answer & Explanation

. Serum alkaline phosphatase (ALP)

Explanation

Elevated levels of serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) at the time of initial diagnosis are recognized as independent negative prognostic factors in osteosarcoma. They generally correlate with a higher tumor burden and poorer overall survival.

Question 5729

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a diaphyseal femur lesion showing an onion-skin periosteal reaction. Histology reveals small blue round cells. Which of the following cytogenetic abnormalities is most characteristic of this tumor?

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

Correct Answer & Explanation

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

Explanation

The clinical and histologic picture describes Ewing sarcoma. The most common translocation associated with this tumor is t(11;22)(q24;q12), which results in the EWS-FLI1 fusion protein.

Question 5730

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with progressive thigh pain. Radiographs demonstrate an aggressive, permeative lytic lesion in the diaphysis of the femur with an "onion-skin" periosteal reaction. A biopsy is obtained. Which of the following genetic translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma typically presents in the diaphysis of long bones in children and is associated with a characteristic "onion-skin" periosteal reaction. It is defined molecularly by the t(11;22) chromosomal translocation, resulting in the EWS-FLI1 fusion protein.

Question 5731

Topic: Bone Tumors

A 16-year-old boy presents with aching pain in his proximal tibia that is significantly worse at night and is dramatically relieved by taking ibuprofen. Radiographs reveal a cortical sclerosis surrounding a small radiolucent nidus. The pathophysiology of this lesion's pain mechanism is primarily driven by high levels of which substance?

. Prostaglandin E2
. Interleukin-1
. Tumor necrosis factor-alpha
. Leukotriene B4
. Bradykinin

Correct Answer & Explanation

. Prostaglandin E2

Explanation

The classic presentation describes an osteoid osteoma. The nidus of an osteoid osteoma produces high concentrations of Prostaglandin E2 (PGE2) due to elevated cyclooxygenase-2 (COX-2) expression, which mediates the characteristic night pain that responds well to NSAIDs.

Question 5732

Topic: 10. Pathology and Oncology

A 16-year-old male presents with a suspicious lesion in the distal femur, highly concerning for osteosarcoma. A biopsy is planned. Which principle is most critical to ensure optimal management and potential limb salvage?

. The biopsy incision should be transverse to minimize scarring.
. The biopsy should be performed through the largest muscle belly to allow for adequate tissue sampling.
. The biopsy tract must be planned such that it can be completely excised en bloc with the tumor during definitive surgery.
. Neurovascular structures should be meticulously avoided, even if it compromises direct access to the lesion.
. A percutaneous core needle biopsy is always superior to an open incisional biopsy for diagnostic yield.

Correct Answer & Explanation

. The biopsy tract must be planned such that it can be completely excised en bloc with the tumor during definitive surgery.

Explanation

For suspected bone tumors like osteosarcoma, the biopsy technique is paramount and can significantly impact the patient's prognosis and potential for limb salvage. The most critical principle is that the biopsy tract must be meticulously planned and performed so that it can be completely excised en bloc with the tumor during the definitive oncologic resection. A contaminated biopsy tract can necessitate a wider margin of resection or even amputation if not properly managed. Transverse incisions are generally avoided in extremities, and planning through muscle bellies should also consider the definitive surgical approach. While avoiding neurovascular structures is important, it shouldn't completely compromise access or proper planning. The choice between core needle and open biopsy depends on the tumor and institutional expertise, and neither is 'always superior'.

Question 5733

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive knee pain and a palpable mass over the distal femur. Radiographs reveal a mixed lytic and sclerotic lesion with a 'sunburst' periosteal reaction. Biopsy confirms high-grade intramedullary osteosarcoma. What is the most widely accepted standard of care?

. Immediate transfemoral amputation followed by radiation therapy
. Radiation therapy followed by wide surgical resection
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Wide surgical resection alone
. Adjuvant chemotherapy followed by local radiation therapy

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

Osteosarcoma is treated optimally with a combination of neoadjuvant chemotherapy, wide surgical resection (limb salvage when possible), and adjuvant chemotherapy. This multimodal approach significantly improves long-term survival rates compared to surgery alone.

Question 5734

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with progressive mid-thigh pain and fevers. Radiographs show a permeative diaphyseal lesion with an 'onion skin' periosteal reaction. A biopsy reveals a small, round, blue cell tumor. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is classically characterized by the t(11;22) chromosomal translocation, which results in the EWS-FLI1 fusion protein. This genetic marker is diagnostic and essential in differentiating it from other small round blue cell tumors.

Question 5735

Topic: 10. Pathology and Oncology

A 15-year-old male presents with deep, aching distal femur pain. Plain radiographs reveal a mixed lytic and sclerotic lesion in the distal femoral metaphysis with a sunburst periosteal reaction. What is the most appropriate next step in management before performing a biopsy?

. Initiate neoadjuvant chemotherapy
. Perform a marginal excision
. Obtain MRI of the entire femur and a chest CT
. Perform a fine needle aspiration (FNA) in the clinic
. Administer local radiation therapy

Correct Answer & Explanation

. Obtain MRI of the entire femur and a chest CT

Explanation

The clinical and radiographic presentation is highly suspicious for osteosarcoma. Prior to any biopsy, complete local and systemic staging must be performed, including an MRI of the entire involved bone (to check for skip lesions) and a chest CT (to evaluate for pulmonary metastases).

Question 5736

Topic: 10. Pathology and Oncology

An 11-year-old boy presents with pain and swelling in his left mid-thigh. Radiographs show a permeative diaphyseal lesion with an 'onion-skin' periosteal reaction. Which of the following cytogenetic abnormalities is most characteristically associated with this tumor?

. t(11;22)(q24;q12)
. t(X;18)(p11;q11)
. t(9;22)(q22;q12)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)

Correct Answer & Explanation

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

Explanation

Ewing sarcoma classically presents with a permeative diaphyseal lesion and 'onion-skin' periostitis. It is genetically characterized by the t(11;22)(q24;q12) translocation, resulting in the EWS-FLI1 fusion gene.

Question 5737

Topic: Bone Tumors

A 15-year-old boy presents with progressive knee pain and swelling. Radiographs show a destructive metaphyseal lesion in the distal femur with a sunburst periosteal reaction and Codman's triangle. Biopsy confirms high-grade osteosarcoma. What is the most appropriate treatment algorithm?

. Immediate amputation
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Wide surgical resection followed by radiation therapy
. Radiation therapy followed by wide surgical resection
. Intralesional curettage with bone grafting

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

High-grade osteosarcoma is treated with a combination of neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy. Radiation therapy is generally ineffective for osteosarcoma and is reserved for highly specific, unresectable cases.

Question 5738

Topic: 10. Pathology and Oncology

A 32-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic, expansile lesion in the epiphysis of the proximal tibia without a sclerotic margin. MRI shows no soft tissue extension. Biopsy confirms mononuclear cells with scattered multinucleated giant cells. What is the standard surgical treatment?

. En bloc resection with endoprosthetic reconstruction
. Extended intralesional curettage, high-speed burring, and bone cement packing
. Amputation above the knee
. Observation with serial radiographs
. Primary radiation therapy

Correct Answer & Explanation

. Extended intralesional curettage, high-speed burring, and bone cement packing

Explanation

Giant cell tumors (GCT) of bone are locally aggressive epiphyseal lesions typically seen in young adults. Standard treatment involves extended intralesional curettage with chemical or thermal adjuvants (e.g., high-speed burr, phenol) and packing with polymethylmethacrylate (PMMA) to reduce recurrence risk.

Question 5739

Topic: 10. Pathology and Oncology

A 32-year-old female presents with progressive knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion in the distal femur without sclerotic margins. Biopsy shows multinucleated giant cells in a background of mononuclear stromal cells. Which of the following is the most appropriate initial surgical management?

. En bloc resection and endoprosthetic reconstruction
. Intralesional curettage, high-speed burring, and bone cement packing
. Amputation above the knee
. Radiation therapy alone
. Core needle biopsy followed by neoadjuvant chemotherapy

Correct Answer & Explanation

. Intralesional curettage, high-speed burring, and bone cement packing

Explanation

Giant cell tumors are locally aggressive, benign bone tumors usually affecting the epiphyses of long bones. The standard of care for resectable lesions is extended intralesional curettage using chemical or thermal adjuvants, followed by filling the defect with polymethylmethacrylate (PMMA).

Question 5740

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with knee pain. Radiographs reveal a sunburst periosteal reaction and Codman's triangle in the distal femur. Biopsy confirms osteosarcoma. Which of the following genetic alterations is most closely associated with this condition?

. t(11;22) translocation
. t(X;18) translocation
. Mutation in the RB1 gene
. Mutation in the GNAS1 gene
. t(12;16) translocation

Correct Answer & Explanation

. Mutation in the RB1 gene

Explanation

Mutations in the Retinoblastoma (RB1) and p53 tumor suppressor genes are strongly associated with osteosarcoma. The t(11;22) translocation is characteristic of Ewing sarcoma, t(X;18) of synovial sarcoma, GNAS1 mutation of fibrous dysplasia, and t(12;16) of myxoid liposarcoma.

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