Menu

10. Pathology and Oncology MCQs

Practice Set 122 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 2421

Topic: 10. Pathology and Oncology
Following neoadjuvant chemotherapy for conventional high-grade osteosarcoma, surgical resection is performed. According to the Huvos grading system, what percentage of tumor necrosis is considered a 'good response' and is the most significant prognostic factor for long-term survival?
. Greater than 50%
. Greater than 75%
. Greater than 90%
. Greater than 95%
. 100% only

Correct Answer & Explanation

. Greater than 90%

Explanation

The percentage of tumor necrosis following neoadjuvant chemotherapy is the most important prognostic factor for conventional osteosarcoma. A 'good response' is defined as at least 90% tumor necrosis (Huvos Grade III is 90-99% and Grade IV is 100% necrosis). Patients with >=90% necrosis have a significantly better 5-year survival rate compared to poor responders (<90% necrosis).

Question 2422

Topic: 10. Pathology and Oncology

A 62-year-old female with breast cancer presents with right thigh pain. Radiographs reveal a lytic metastatic lesion in the peritrochanteric region of the right femur, involving greater than 2/3 of the cortical diameter. She describes moderate pain with weight-bearing. Using Mirels' criteria, what is her score and the recommended management regarding prophylactic fixation?

. Score 8; radiotherapy alone is indicated
. Score 9; prophylactic internal fixation is highly recommended
. Score 10; prophylactic internal fixation is highly recommended
. Score 11; prophylactic internal fixation is highly recommended
. Score 7; conservative management with bisphosphonates

Correct Answer & Explanation

. Score 11; prophylactic internal fixation is highly recommended

Explanation

Mirels' criteria assess the risk of impending pathologic fracture based on four categories, each scoring 1 to 3 points: Site (Upper extremity=1, Lower extremity=2, Peritrochanteric=3), Pain (Mild=1, Moderate=2, Functional=3), Lesion Nature (Blastic=1, Mixed=2, Lytic=3), and Size (<1/3 cortex=1, 1/3-2/3 cortex=2, >2/3 cortex=3). Calculation: Peritrochanteric (3) + Moderate pain (2) + Lytic (3) + Size >2/3 (3) = 11. A Mirels' score of >= 9 indicates a high risk of fracture, and prophylactic internal fixation is highly recommended.

Question 2423

Topic: 10. Pathology and Oncology

A 60-year-old male presents with a destructive radiolucent lesion in his proximal femur. Histological examination reveals two distinct morphological components: a well-differentiated hyaline cartilage tumor sharply juxtaposed against a high-grade, non-cartilaginous spindle cell sarcoma. What is the most likely diagnosis?

. Osteosarcoma
. Clear cell chondrosarcoma
. Dedifferentiated chondrosarcoma
. Mesenchymal chondrosarcoma
. Ewing sarcoma

Correct Answer & Explanation

. Dedifferentiated chondrosarcoma

Explanation

Dedifferentiated chondrosarcoma is characterized by a bimorphic histological appearance featuring a low-grade cartilage tumor abruptly adjacent to a high-grade, non-cartilaginous sarcoma (often resembling osteosarcoma, fibrosarcoma, or undifferentiated pleomorphic sarcoma). This typically occurs in older adults and carries a poor prognosis.

Question 2424

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a painful mass in the diaphysis of his left femur. Radiographs show a permeative, destructive lesion with an 'onion-skin' periosteal reaction. A core needle biopsy is performed. Which of the following chromosomal translocations is most characteristic of the suspected diagnosis?

. t(X;18)(p11;q11)
. t(11;22)(q24;q12)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)
. 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 by the t(11;22)(q24;q12) translocation, which results in the EWS-FLI1 fusion protein. t(X;18) is seen in synovial sarcoma. t(12;16) is seen in myxoid liposarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(9;22) is the Philadelphia chromosome seen in CML and occasionally in some chondrosarcomas.

Question 2425

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a destructive diaphyseal lesion of the femur with a multilamellated 'onion-skin' periosteal reaction. Biopsy reveals uniform small round blue cells. Which chromosomal translocation is most characteristically associated with this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and histological picture describes Ewing sarcoma. The most common chromosomal translocation is t(11;22)(q24;q12), which results in the EWS-FLI1 fusion protein and is found in approximately 85-90% of Ewing sarcoma cases. The t(X;18) translocation is associated with synovial sarcoma, and t(2;13) is associated with alveolar rhabdomyosarcoma.

Question 2426

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a rapidly enlarging soft tissue mass in his forearm. Biopsy reveals small round blue cells. Cytogenetic analysis demonstrates a t(2;13) chromosomal translocation. What is the most likely diagnosis?

. Ewing sarcoma
. Synovial sarcoma
. Alveolar rhabdomyosarcoma
. Clear cell sarcoma
. Myxoid liposarcoma

Correct Answer & Explanation

. Alveolar rhabdomyosarcoma

Explanation

The t(2;13) chromosomal translocation is characteristic of alveolar rhabdomyosarcoma, resulting in the PAX3-FOXO1 fusion gene. Ewing sarcoma is associated with t(11;22), synovial sarcoma with t(X;18), clear cell sarcoma with t(12;22), and myxoid liposarcoma with t(12;16).

Question 2427

Topic: 10. Pathology and Oncology

According to Mirels' criteria for predicting the risk of a pathologic fracture through a metastatic bone lesion, which of the following scenarios yields the highest possible score (3 points) for its respective category?

. Lesion located in the upper extremity
. Lesion is blastic in radiographic appearance
. Lesion involves less than 1/3 of the cortical diameter
. Patient experiences severe pain with functional loading
. Lesion located in the diaphyseal region of the femur

Correct Answer & Explanation

. Patient experiences severe pain with functional loading

Explanation

Mirels' scoring system evaluates Site, Pain, Lesion type, and Size (1 to 3 points each). Pain: Mild (1), Moderate (2), Severe/Functional (3). Site: Upper extremity (1), Lower extremity (2), Peritrochanteric (3). Lesion type: Blastic (1), Mixed (2), Lytic (3). Size: <1/3 cortex (1), 1/3 to 2/3 (2), >2/3 (3). Therefore, severe pain yields 3 points. Diaphyseal lower extremity yields 2 points.

Question 2428

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with an aggressive diaphyseal lesion of the femur. Biopsy reveals small round blue cells. Molecular testing is positive for the t(11;22)(q24;q12) chromosomal translocation. Which fusion gene product is characteristic of this tumor?

. BCR-ABL
. EWS-FLI1
. SYT-SSX
. PAX3-FOXO1
. TLS-CHOP

Correct Answer & Explanation

. EWS-FLI1

Explanation

The clinical presentation and histology are classic for Ewing sarcoma. Over 85% of Ewing sarcomas exhibit the t(11;22)(q24;q12) translocation, which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11, resulting in the EWS-FLI1 fusion protein. SYT-SSX is found in synovial sarcoma, PAX3-FOXO1 in alveolar rhabdomyosarcoma, and TLS-CHOP in myxoid liposarcoma.

Question 2429

Topic: 10. Pathology and Oncology

A 22-year-old male presents with chronic, painful scoliosis. Radiographs demonstrate a 3.0 cm expansile, lytic lesion with a sclerotic rim in the pedicle of the L3 vertebra. The patient reports that his pain is dull, aching, and not reliably relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). What is the most likely diagnosis?

. Osteoid osteoma
. Osteoblastoma
. Aneurysmal bone cyst
. Giant cell tumor
. Multiple myeloma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Osteoblastoma is a benign bone-forming tumor that is histologically identical to an osteoid osteoma but is distinguished clinically and radiographically. Osteoblastomas are typically larger than 2 cm, frequently involve the posterior elements of the spine (causing painful scoliosis), tend to be progressive, and characteristically do NOT have the dramatic pain relief with NSAIDs seen in osteoid osteomas.

Question 2430

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with knee pain and a palpable mass in the distal femur. Radiographs show a permeative, destructive lesion in the metaphysis with a 'sunburst' periosteal reaction. Biopsy reveals sheets of uniform, small round blue cells. Immunohistochemistry is strongly positive for CD99 (MIC2). Which chromosomal translocation is most characteristic of this tumor?

. 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

The patient has Ewing sarcoma, characterized by small round blue cells and CD99 positivity. The most common chromosomal translocation is t(11;22)(q24;q12), which results in the EWS-FLI1 fusion protein. t(X;18) is seen in synovial sarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(12;16) is seen in myxoid liposarcoma.

Question 2431

Topic: Bone Tumors

A 16-year-old male complains of severe night pain in his right mid-thigh that is dramatically relieved by aspirin. Radiographs show a thickened cortical diaphyseal area with a 7 mm radiolucent nidus. What is the most appropriate initial definitive treatment for this condition?

. En bloc wide resection of the diaphyseal cortex
. External beam radiation therapy
. Neoadjuvant chemotherapy followed by curettage
. Radiofrequency ablation (RFA)
. Below-knee amputation

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical presentation (night pain relieved by NSAIDs/aspirin) and radiographic findings (cortical thickening with a <1.5 cm radiolucent nidus) are classic for an osteoid osteoma. The standard of care for definitive treatment, if conservative medical management fails or is undesired, is minimally invasive CT-guided Radiofrequency Ablation (RFA).

Question 2432

Topic: 10. Pathology and Oncology

In the treatment of osteosarcoma, which of the following is the most important prognostic factor for long-term overall survival?

. The initial size of the tumor
. The percentage of tumor necrosis following neoadjuvant chemotherapy
. The patient's age at diagnosis
. The anatomic location of the primary tumor
. The specific histologic subtype of osteosarcoma

Correct Answer & Explanation

. The percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The most powerful predictor of long-term survival in patients with non-metastatic osteosarcoma is the histologic response of the tumor to neoadjuvant chemotherapy, defined by the percentage of tumor necrosis at the time of definitive resection. A good response is typically defined as >= 90% necrosis.

Question 2433

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a painless, slow-growing mass on the posterior aspect of her distal thigh. Radiographs demonstrate a dense, lobulated, ossified mass attached to the posterior cortex of the distal femur via a broad base, with a 'string sign' radiolucent cleft. Genetic analysis of this tumor is most likely to reveal an amplification of which of the following genes?

. EWS-FLI1
. EXT1
. MDM2
. RB1
. GNAS

Correct Answer & Explanation

. MDM2

Explanation

The clinical and radiographic presentation is classic for a parosteal osteosarcoma (dense surface lesion, posterior distal femur, 'string sign' separating the tumor from the cortex). Parosteal osteosarcomas are low-grade surface osteosarcomas characterized cytogenetically by ring chromosomes containing an amplification of the 12q13-15 region, which includes the MDM2 and CDK4 genes.

Question 2434

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a slow-growing, painful mass near her knee joint. Biopsy reveals a biphasic tumor demonstrating both epithelial and spindle cell components. Which of the following chromosomal translocations is most characteristic of this lesion?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The clinical and histologic description is classic for synovial sarcoma. Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene. t(11;22) is seen in Ewing sarcoma; t(12;16) in myxoid liposarcoma; t(9;22) in extraskeletal myxoid chondrosarcoma; and t(2;13) in alveolar rhabdomyosarcoma.

Question 2435

Topic: 10. Pathology and Oncology

A 60-year-old male presents with deep thigh pain. Radiographs of the proximal femur demonstrate a large intramedullary lesion with endosteal scalloping and intralesional 'rings and arcs' calcification. Biopsy confirms a Grade 2 conventional chondrosarcoma. What is the standard and most definitive surgical treatment for this lesion?

. Intralesional curettage, adjuvant phenol, and bone grafting
. Preoperative radiation followed by wide surgical resection
. Neoadjuvant chemotherapy followed by wide surgical resection
. Wide surgical resection with negative margins
. Amputation at the hip joint

Correct Answer & Explanation

. Wide surgical resection with negative margins

Explanation

Conventional chondrosarcomas, particularly Grades 2 and 3, are notoriously resistant to both chemotherapy and radiation. The mainstay of treatment is wide surgical resection achieving negative margins. While intralesional curettage may be acceptable for benign enchondromas or selected Grade 1 atypical cartilaginous tumors in the appendicular skeleton, Grade 2 lesions require wide excision to prevent recurrence and metastasis.

Question 2436

Topic: 10. Pathology and Oncology
A 16-year-old boy completes neoadjuvant chemotherapy for a conventional high-grade distal femoral osteosarcoma, followed by wide surgical resection. Histopathologic analysis of the resected specimen reveals 95% tumor necrosis. According to the Huvos grading system, what grade does this response represent, and how does it affect prognosis?
. Grade II; it is considered a poor response with an unfavorable prognosis
. Grade III; it is considered a good response with a favorable prognosis
. Grade III; it is considered a poor response with an unfavorable prognosis
. Grade IV; it is considered a good response with a favorable prognosis
. Grade IV; it is considered a poor response with an unfavorable prognosis

Correct Answer & Explanation

. Grade III; it is considered a good response with a favorable prognosis

Explanation

The Huvos grading system evaluates histologic response to chemotherapy in osteosarcoma. Grade I: little or no necrosis (<50%). Grade II: 50-90% necrosis. Grade III: >90% necrosis but with identifiable viable tumor cells. Grade IV: 100% necrosis (no viable cells). A response of 90% or greater (Grades III and IV) is considered a 'good response' and is the most important positive prognostic indicator for long-term survival in osteosarcoma patients.

Question 2437

Topic: 10. Pathology and Oncology

While soft tissue sarcomas generally metastasize hematogenously to the lungs, certain subtypes have a higher propensity for lymphatic spread to regional lymph nodes. Which of the following soft tissue sarcomas is most likely to exhibit lymphatic metastasis?

. Pleomorphic undifferentiated sarcoma
. Fibrosarcoma
. Synovial sarcoma
. Liposarcoma
. Malignant peripheral nerve sheath tumor

Correct Answer & Explanation

. Synovial sarcoma

Explanation

Soft tissue sarcomas that commonly metastasize to lymph nodes can be remembered by the mnemonic RSECA: Rhabdomyosarcoma, Synovial sarcoma, Epithelioid sarcoma, Clear cell sarcoma, and Angiosarcoma. Synovial sarcoma has a well-documented propensity for lymphatic spread compared to other adult soft tissue sarcomas.

Question 2438

Topic: 10. Pathology and Oncology

A 60-year-old woman with metastatic breast cancer presents with a newly identified lytic lesion in her left peritrochanteric femur. The lesion involves 50% of the cortical diameter. She reports moderate, aching pain with weight-bearing. Using Mirels' criteria, what is her calculated score, and what is the recommendation?

. Score 7; Observation with local radiation
. Score 8; Observation and bisphosphonates
. Score 9; Prophylactic internal fixation
. Score 10; Prophylactic internal fixation
. Score 11; Neoadjuvant chemotherapy before surgery

Correct Answer & Explanation

. Score 10; Prophylactic internal fixation

Explanation

Mirels' scoring system for impending pathologic fractures assigns 1, 2, or 3 points for four categories. Site: Upper limb (1), Lower limb (2), Peritrochanteric (3). Pain: Mild (1), Moderate (2), Severe (3). Size: <1/3 (1), 1/3-2/3 (2), >2/3 (3). Type: Blastic (1), Mixed (2), Lytic (3). This patient's score: Peritrochanteric (3) + Moderate pain (2) + Size 50% (2) + Lytic (3) = 10. A score >= 9 is a strong indication for prophylactic fixation.

Question 2439

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a deep, slow-growing soft tissue mass in his thigh near the knee joint. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Molecular testing of the biopsy specimen is most likely to identify which of the following chromosomal translocations?

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

Correct Answer & Explanation

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

Explanation

The clinical and histological description is classic for a synovial sarcoma (a deep soft tissue mass near a joint in a young adult, with biphasic histology). Synovial sarcoma is uniquely characterized by the t(X;18)(p11;q11) chromosomal translocation, which results in the SYT-SSX fusion gene. The t(11;22) is seen in Ewing sarcoma, t(12;16) in myxoid liposarcoma, t(9;22) in extraskeletal myxoid chondrosarcoma, and t(2;13) in alveolar rhabdomyosarcoma.

Question 2440

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic hip pain. Radiographs demonstrate a lytic lesion with intralesional calcifications located strictly in the epiphysis of the proximal femur. Biopsy reveals cells with abundant clear cytoplasm and central nuclei, arranged in a lobular pattern. Based on the clinical demographic and location, what is the most likely diagnosis?

. Chondroblastoma
. Giant Cell Tumor
. Clear Cell Chondrosarcoma
. Enchondroma
. Osteosarcoma

Correct Answer & Explanation

. Clear Cell Chondrosarcoma

Explanation

Clear cell chondrosarcoma is a rare, low-grade malignant bone tumor that characteristically arises in the epiphysis of long bones (most commonly the proximal femur or proximal humerus). It often clinically and radiographically mimics chondroblastoma. However, chondroblastoma typically occurs in patients with open physes or under the age of 20, whereas clear cell chondrosarcoma usually presents in adults aged 20 to 50 years. The histology featuring cells with clear cytoplasm confirms the diagnosis.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page