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10. Pathology and Oncology MCQs

Practice Set 125 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 2481

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a slow-growing, painful mass near his knee joint. An incisional biopsy confirms the diagnosis of synovial sarcoma. Which of the following chromosomal translocations is uniquely diagnostic for this soft tissue malignancy?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characteristically defined by the t(X;18)(p11;q11) chromosomal translocation, which results in the SYT-SSX fusion gene (specifically SYT-SSX1, SYT-SSX2, or rarely SYT-SSX4). This molecular marker is present in over 90% of cases and is key for diagnostic confirmation. Options A, B, D, and E represent translocations for Ewing sarcoma, CML/Chondrosarcoma, myxoid liposarcoma, and alveolar rhabdomyosarcoma, respectively.

Question 2482

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive, nocturnal thigh pain and a low-grade fever. Radiographs demonstrate a permeative, diaphyseal lesion in the femur with an extensive periosteal 'onion-skin' reaction. Core needle biopsy reveals sheets of uniform small, round, blue cells. Which of the following cytogenetic translocations is most characteristically associated with this specific neoplasm?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical presentation, radiographic 'onion-skin' periosteal reaction, and histology (small round blue cells) are classic for Ewing sarcoma. The pathognomonic cytogenetic abnormality in over 90% of Ewing sarcoma cases is the t(11;22)(q24;q12) translocation, which results in the EWS-FLI1 fusion protein.

Question 2483

Topic: 10. Pathology and Oncology

A 25-year-old female presents with chronic aching in her anterior leg. Radiographs reveal an expansile, multilocular, radiolucent lesion in the diaphysis of the tibia. Biopsy demonstrates a biphasic tumor with nests of epithelial cells in a fibrous stroma. What is the most appropriate definitive management?

. Curettage, burring, and bone grafting
. Neoadjuvant chemotherapy followed by marginal excision
. Radiation therapy
. Wide surgical resection
. Amputation

Correct Answer & Explanation

. Wide surgical resection

Explanation

The clinical, radiographic, and histologic descriptions (epithelial and mesenchymal cells in the tibial diaphysis) are pathognomonic for adamantinoma. It is a low-grade, slow-growing malignant bone tumor. Because it is resistant to chemotherapy and radiation, and has a high local recurrence rate with intralesional procedures, the treatment of choice is wide surgical resection with limb salvage reconstruction.

Question 2484

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with pain and swelling over his mid-thigh. Radiographs demonstrate a permeative, destructive lytic lesion in the femoral diaphysis with a prominent 'onion skin' periosteal reaction. Core needle biopsy confirms a small round blue cell tumor. Which of the following chromosomal translocations is most pathognomonic for this disease?

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

Correct Answer & Explanation

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

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation in >90% of cases, resulting in the EWS-FLI1 fusion protein. t(X;18) is associated with synovial sarcoma; t(9;22) with CML (Philadelphia chromosome); t(12;16) with myxoid liposarcoma; and t(2;13) with alveolar rhabdomyosarcoma.

Question 2485

Topic: 10. Pathology and Oncology
A 14-year-old male undergoes neoadjuvant chemotherapy followed by wide surgical resection of an osteosarcoma of the distal femur. Pathological evaluation of the resected specimen is performed. Which of the following findings is the most significant predictor of long-term survival?
. Tumor volume less than 100 cm3
. Clear surgical margins > 2 cm
. Greater than 90% tumor necrosis in response to chemotherapy
. Absence of vascular invasion on histology
. Predominance of chondroblastic subtype over osteoblastic subtype

Correct Answer & Explanation

. Greater than 90% tumor necrosis in response to chemotherapy

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for long-term survival in conventional high-grade osteosarcoma. Greater than 90% necrosis (Huvos grade III or IV) defines a 'good responder' and is associated with significantly higher survival rates compared to poor responders.

Question 2486

Topic: 10. Pathology and Oncology
A 60-year-old male presents with deep hip pain. Radiographs show a large, purely lytic lesion in the periacetabular ilium with endosteal scalloping and focal cortical breakthrough. Biopsy confirms a Grade II (intermediate-grade) conventional chondrosarcoma. What is the treatment of choice?
. Neoadjuvant chemotherapy followed by wide surgical resection
. Intralesional curettage with phenol adjuvant and cementation
. Wide surgical resection alone
. Primary radiation therapy
. Wide surgical resection followed by adjuvant chemotherapy

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas are notoriously resistant to both chemotherapy and radiation therapy. For intermediate (Grade II) and high-grade (Grade III) lesions, as well as any conventional chondrosarcoma with aggressive imaging features (cortical breakthrough, large size in pelvis), the definitive treatment is wide surgical resection alone to achieve negative margins.

Question 2487

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slowly enlarging, painful mass deep in the thigh near the knee joint. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Cytogenetic analysis is ordered. Which of the following chromosomal translocations is highly specific for this diagnosis?

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

Correct Answer & Explanation

. t(X;18)(p11;q11)

Explanation

The clinical scenario and biopsy describe a Synovial Sarcoma. The highly specific chromosomal translocation for synovial sarcoma is t(X;18)(p11.2;q11.2), which results in the SYT-SSX fusion gene. t(11;22) is Ewing's sarcoma; t(9;22) is Extraskeletal myxoid chondrosarcoma; t(2;13) is Alveolar rhabdomyosarcoma; t(12;16) is Myxoid liposarcoma.

Question 2488

Topic: 10. Pathology and Oncology

A 66-year-old female with a known history of multiple myeloma complains of progressively worsening pain in her right thigh. Radiographs demonstrate a purely lytic lesion in the peritrochanteric region of her right femur. The lesion spans 60% of the bone's cross-sectional diameter. She rates her pain as moderate, occurring mainly with weight-bearing. Applying Mirels' criteria, what is her cumulative score and the appropriate clinical recommendation?

. Score 8; Observation and radiation therapy
. Score 9; Prophylactic internal fixation
. Score 10; Prophylactic internal fixation
. Score 11; Amputation
. Score 12; Neoadjuvant chemotherapy followed by wide resection

Correct Answer & Explanation

. Score 10; Prophylactic internal fixation

Explanation

Mirels' scoring system determines the risk of pathologic fracture and the need for prophylactic fixation. It is based on 4 categories (1 to 3 points each): Site (Upper extremity=1, Lower extremity=2, Peritrochanteric=3); Pain (Mild=1, Moderate=2, Severe=3); Size (<1/3=1, 1/3-2/3=2, >2/3=3); and Radiographic nature (Blastic=1, Mixed=2, Lytic=3). For this patient: Site = Peritrochanteric (3); Pain = Moderate (2); Size = 60%, which is between 1/3 and 2/3 (2); Nature = Lytic (3). Total Score = 3 + 2 + 2 + 3 = 10. A score >= 9 dictates prophylactic internal fixation.

Question 2489

Topic: 10. Pathology and Oncology

A 16-year-old male presents with severe pain and swelling in his distal thigh. Radiographs display a destructive metaphyseal lesion with a "sunburst" periosteal reaction and Codman's triangle. MRI suggests an intramedullary osteosarcoma. You plan to perform an open biopsy. Which of the following is an essential surgical oncology principle regarding the biopsy technique?

. The biopsy incision should be placed transversely to follow Langer's lines for improved cosmesis
. The biopsy tract must be oriented longitudinally and positioned so it can be excised en bloc during definitive tumor resection
. An excisional biopsy is strictly preferred over a core needle biopsy to ensure adequate tissue sampling
. The biopsy should traverse multiple muscle compartments to ensure adequate margins around the biopsy tract
. A tourniquet should be inflated during the procedure and deflated before closure to clear tumor cells from the field

Correct Answer & Explanation

. The biopsy tract must be oriented longitudinally and positioned so it can be excised en bloc during definitive tumor resection

Explanation

The biopsy tract in a suspected malignant bone tumor is considered contaminated with tumor cells. A fundamental principle of orthopedic oncology is that the biopsy tract must be meticulously planned (usually longitudinally) so that it lies directly within the planned definitive surgical incision. This allows the entire tract to be completely excised en bloc with the tumor during the definitive wide resection. Transverse incisions or traversing clean compartments drastically complicates future limb-salvage surgery and may necessitate amputation.

Question 2490

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive thigh pain. Radiographs demonstrate a permeative diaphyseal lesion in the femur with a multilaminated 'onion skin' periosteal reaction. A biopsy confirms Ewing sarcoma. Which of the following chromosomal translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

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

Explanation

Ewing sarcoma is classically associated with the t(11;22)(q24;q12) translocation, which leads to the fusion of the EWSR1 gene on chromosome 22 with the FLI1 gene on chromosome 11. t(9;22) is seen in CML; t(12;16) in myxoid liposarcoma; t(X;18) in synovial sarcoma; and t(2;13) in alveolar rhabdomyosarcoma.

Question 2491

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive knee pain. Radiographs demonstrate a permeative diaphyseal lesion in the femur with a laminated 'onion-skin' periosteal reaction. Histology reveals sheets of small round blue cells. Which of the following chromosomal translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

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

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. Ewing sarcoma is characterized histologically as a small round blue cell tumor and is associated with the t(11;22)(q24;q12) translocation in over 90% of cases, resulting in the EWS-FLI1 fusion protein. t(X;18) is associated with synovial sarcoma; t(2;13) with alveolar rhabdomyosarcoma; t(12;16) with myxoid liposarcoma.

Question 2492

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a destructive diaphyseal lesion of the femur with a large soft tissue mass. Biopsy shows uniform small round blue cells. Cytogenetic analysis reveals a t(11;22)(q24;q12) translocation. Which of the following fusion genes is responsible for the pathogenesis of this tumor?

. SYT-SSX1
. EWSR1-FLI1
. PAX3-FOXO1
. EWS-ATF1
. COL1A1-PDGFB

Correct Answer & Explanation

. EWSR1-FLI1

Explanation

The patient has Ewing sarcoma, characterized by the t(11;22) translocation, which results in the EWSR1-FLI1 fusion gene. SYT-SSX1 is seen in synovial sarcoma (t(X;18)). PAX3-FOXO1 is seen in alveolar rhabdomyosarcoma (t(2;13)). EWS-ATF1 is seen in clear cell sarcoma (t(12;22)). COL1A1-PDGFB is seen in dermatofibrosarcoma protuberans.

Question 2493

Topic: 10. Pathology and Oncology

A 45-year-old man presents with a painful shoulder. Imaging reveals a large cartilaginous tumor in the proximal humerus with endosteal scalloping and soft tissue extension. Biopsy confirms a Grade II chondrosarcoma. Molecular testing is most likely to reveal a mutation in which of the following genes?

. EXT1
. IDH1 or IDH2
. GNAS
. RB1
. TP53

Correct Answer & Explanation

. IDH1 or IDH2

Explanation

Mutations in Isocitrate Dehydrogenase 1 or 2 (IDH1/IDH2) are highly prevalent (up to 50-60%) in central chondrosarcomas and enchondromas (as seen in Ollier disease and Maffucci syndrome). EXT1/EXT2 mutations are associated with osteochondromas. GNAS mutations are seen in fibrous dysplasia. RB1 and TP53 are more commonly associated with osteosarcoma.

Question 2494

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive thigh pain. Radiographs reveal a destructive diaphyseal lesion in the femur with a 'lamellated' or 'onion-skin' periosteal reaction. Biopsy shows uniform small round blue cells. The most likely genetic translocation associated with this tumor results in a fusion gene that acts as an aberrant transcription factor. Which translocation is diagnostic?

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

Correct Answer & Explanation

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

Explanation

The clinical and radiographic presentation is classic for Ewing Sarcoma. The hallmark genetic mutation is a balanced reciprocal translocation t(11;22)(q24;q12), creating the EWS-FLI1 fusion protein, which is found in about 85% of cases. t(X;18) is Synovial Sarcoma; t(12;16) is Myxoid Liposarcoma; t(2;13) is Alveolar Rhabdomyosarcoma.

Question 2495

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a permeative lytic lesion in the diaphysis of the femur with an associated 'onion-skin' periosteal reaction. A biopsy confirms Ewing sarcoma. Which of the following cytogenetic abnormalities is most characteristic of this diagnosis?

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

Correct Answer & Explanation

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

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation in approximately 85% of cases, which fuses the EWS gene to the FLI1 transcription factor gene. t(X;18) is seen in synovial sarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(9;22) is the Philadelphia chromosome (CML). t(12;16) is seen in myxoid liposarcoma.

Question 2496

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain. Radiographs show a mixed lytic and sclerotic lesion in the distal femur with a 'sunburst' periosteal reaction. A core needle biopsy confirms conventional high-grade osteosarcoma. Which MRI sequence is most accurate for determining the precise longitudinal intramedullary extent (skip lesions) of the tumor for surgical planning?

. T2-weighted fat-suppressed axial images
. T1-weighted longitudinal (sagittal/coronal) images
. Short tau inversion recovery (STIR) axial images
. T1-weighted post-contrast axial images
. Gradient echo axial sequences

Correct Answer & Explanation

. T1-weighted longitudinal (sagittal/coronal) images

Explanation

T1-weighted longitudinal (sagittal or coronal) sequences of the entire involved bone are the most accurate imaging modality for evaluating the intramedullary extent of osteosarcoma and identifying skip metastases. The normal high-signal fatty marrow provides excellent contrast against the low-signal tumor tissue on T1 sequences.

Question 2497

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive thigh pain. Radiographs demonstrate a permeative diaphyseal lesion of the femur with an 'onion skin' periosteal reaction. A biopsy shows sheets of small round blue cells. Which chromosomal translocation is most characteristically associated with this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical, radiographic, and histologic findings describe Ewing Sarcoma. Over 85% of Ewing sarcomas are characterized by the t(11;22)(q24;q12) chromosomal translocation, which results in the EWS-FLI1 fusion gene. t(9;22) is seen in CML or extraskeletal myxoid chondrosarcoma; t(X;18) in synovial sarcoma; t(12;16) in myxoid liposarcoma; and t(2;13) in alveolar rhabdomyosarcoma.

Question 2498

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful, swollen thigh. Radiographs show a permeative diaphyseal lesion with a periosteal 'onion-skin' reaction in the femur. Biopsy confirms Ewing sarcoma. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

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

Explanation

Ewing sarcoma is classically associated with the t(11;22)(q24;q12) translocation, resulting in the EWS-FLI1 fusion protein. t(X;18) is associated with Synovial Sarcoma; t(12;16) with Myxoid Liposarcoma; t(9;22) with Extraskeletal Myxoid Chondrosarcoma; and t(2;13) with Alveolar Rhabdomyosarcoma.

Question 2499

Topic: 10. Pathology and Oncology
A 60-year-old male is diagnosed with a Grade II conventional chondrosarcoma of the proximal femur. Which of the following is the standard of care for surgical treatment of this lesion?
. Intralesional curettage with phenol adjuvant
. Wide surgical resection
. Radiotherapy alone
. Chemotherapy followed by marginal excision
. Amputation

Correct Answer & Explanation

. Wide surgical resection

Explanation

Conventional chondrosarcomas (Grade II and III) are relatively resistant to both chemotherapy and radiotherapy. The standard treatment is wide surgical resection with negative margins. Intralesional curettage is reserved for benign cartilaginous lesions or select Grade I chondrosarcomas (atypical cartilaginous tumors) in the appendicular skeleton.

Question 2500

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful, swollen left mid-thigh. Radiographs reveal a permeative, destructive diaphyseal lesion of the femur with a laminated 'onion-skin' periosteal reaction. Biopsy demonstrates a proliferation of small round blue cells. Which of the following chromosomal translocations is the most common genetic hallmark of this tumor?

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

Correct Answer & Explanation

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

Explanation

The clinical, radiographic, and histological findings are classic for Ewing sarcoma. The most common chromosomal translocation in Ewing sarcoma is t(11;22)(q24;q12), which fuses the EWSR1 gene on chromosome 22 with the FLI1 gene on chromosome 11. t(X;18) is seen in synovial sarcoma, t(2;13) in alveolar rhabdomyosarcoma, and t(12;16) in myxoid liposarcoma.

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