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10. Pathology and Oncology MCQs

Practice Set 123 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 2441

Topic: Bone Tumors

A 14-year-old boy presents with a painful scoliosis that is worse at night and relieved by NSAIDs. Imaging reveals a radiolucent nidus with surrounding sclerosis in the pedicle of T8 on the right side. How will this scoliotic deformity most likely present clinically?

. Structural curve with severe rotation towards the right
. Non-structural curve with the concavity directed towards the right
. Non-structural curve with the convexity directed towards the right
. Structural curve with the apex at L2
. A compensatory curve secondary to a pelvic obliquity

Correct Answer & Explanation

. Non-structural curve with the concavity directed towards the right

Explanation

Spinal osteoid osteomas typically present in the posterior elements and cause asymmetric muscle spasm, leading to a non-structural scoliosis. The concavity of the curve is typically directed toward the side of the lesion (the right side in this scenario).

Question 2442

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a slowly enlarging, painful soft tissue mass near her knee joint. Biopsy reveals a biphasic spindle cell neoplasm. Cytogenetic analysis is most likely to demonstrate which of the following translocations?

. 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 characterized by the t(X;18) translocation, leading to the SYT-SSX fusion gene. It often presents in young adults as a painful mass near a joint (though rarely intra-articular) and can exhibit biphasic (epithelial and spindle cell) histology.

Question 2443

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with distal femur pain. Imaging reveals a destructive metaphyseal lesion with a 'sunburst' periosteal reaction and a Codman's triangle. Core needle biopsy confirms high-grade intramedullary osteosarcoma. Which of the following genetic mutations or translocations is most strongly associated with the pathogenesis of this tumor?

. t(11;22) translocation
. t(X;18) translocation
. Mutation in the EXT1 gene
. Mutations in the RB1 and TP53 tumor suppressor genes
. t(12;16) translocation

Correct Answer & Explanation

. Mutations in the RB1 and TP53 tumor suppressor genes

Explanation

Osteosarcoma is strongly associated with mutations in tumor suppressor genes, notably RB1 (associated with hereditary retinoblastoma) and TP53 (associated with Li-Fraumeni syndrome). t(11;22) is characteristic of Ewing sarcoma, t(X;18) of synovial sarcoma, EXT1 of hereditary multiple exostoses, and t(12;16) of myxoid liposarcoma.

Question 2444

Topic: 10. Pathology and Oncology

A 65-year-old female with known breast cancer presents with functional, weight-bearing thigh pain. Radiographs demonstrate a purely lytic lesion in the peritrochanteric region of the proximal femur. The lesion spans 50% (1/3 to 2/3) of the cortical diameter. Using Mirels' criteria for impending pathologic fractures, what is her calculated score and the associated clinical recommendation?

. Score 7; local radiotherapy alone is adequate
. Score 8; prophylactic fixation is optional
. Score 9; prophylactic fixation is recommended
. Score 10; prophylactic fixation is recommended
. Score 11; prophylactic fixation is highly recommended

Correct Answer & Explanation

. Score 11; prophylactic fixation is highly recommended

Explanation

Mirels' scoring system evaluates 4 variables (Site, Pain, Lesion, Size), scoring each from 1 to 3. Site: Peritrochanteric = 3. Pain: Functional (aggravated by weight-bearing) = 3. Lesion type: Lytic = 3. Size: 1/3 to 2/3 of cortex = 2. Total score = 3 + 3 + 3 + 2 = 11. A Mirels score of 9 or greater carries a high risk of fracture (>33%), and prophylactic internal fixation is highly recommended.

Question 2445

Topic: 10. Pathology and Oncology

A 14-year-old boy has been diagnosed with a high-grade intramedullary osteosarcoma of the distal femur. He undergoes 10 weeks of neoadjuvant chemotherapy followed by surgical resection. Which of the following parameters obtained from the resected specimen provides the most significant prognostic value for long-term overall survival?

. Percentage of tumor necrosis
. Surgical margin width (greater than 2 cm)
. Presence of chondroblastic elements
. Mitotic index of the residual tumor cells
. Expression of p-glycoprotein

Correct Answer & Explanation

. Percentage of tumor necrosis

Explanation

In the management of high-grade osteosarcoma, the histologic response to neoadjuvant chemotherapy is the single most important prognostic factor for long-term survival. This is quantified by the percentage of tumor necrosis in the resected specimen (Huvos grading system). A 'good' response is defined as greater than 90% tumor necrosis, which correlates with significantly improved disease-free and overall survival rates compared to patients with less than 90% necrosis.

Question 2446

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a deep, slow-growing soft tissue mass in the popliteal fossa. Excisional biopsy confirms a biphasic tumor with both epithelial and spindle cell components. Which of the following cytogenetic abnormalities is classically associated with this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The diagnosis is synovial sarcoma, which classicially presents as a deep soft tissue mass near a joint (often the knee/popliteal fossa) in young adults. Histologically, it can be biphasic (epithelial and spindle cells) or monophasic. It is characterized by the t(X;18)(p11;q11) chromosomal translocation, which results in the SYT-SSX fusion gene. t(11;22) is Ewing sarcoma; t(12;16) is myxoid liposarcoma; t(2;13) is alveolar rhabdomyosarcoma; t(9;22) is extraskeletal myxoid chondrosarcoma (and CML).

Question 2447

Topic: Bone Tumors

A 22-year-old male presents with chronic, dull back pain that is worsened at night. He reports the pain is poorly relieved by aspirin. Radiographs and CT scan reveal a 2.5 cm radiolucent lesion with a sclerotic margin located in the posterior elements of the L3 vertebra. What is the most likely diagnosis?

. Osteoid osteoma
. Osteoblastoma
. Aneurysmal bone cyst
. Eosinophilic granuloma
. Chondroblastoma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Osteoblastoma and osteoid osteoma share similar histological features but are differentiated primarily by size and clinical presentation. Osteoblastomas are typically larger than 2.0 cm (while osteoid osteomas are < 1.5 - 2 cm). Osteoblastomas have a strong predilection for the posterior elements of the spine and produce pain that is less characteristically nocturnal and less dramatically responsive to NSAIDs or aspirin compared to osteoid osteoma.

Question 2448

Topic: 10. Pathology and Oncology

A 30-year-old male presents with chronic anterior leg pain. Radiographs reveal a multi-loculated, eccentric, osteolytic lesion in the anterior cortex of the tibial diaphysis. Biopsy reveals islands of epithelial cells in a fibrous stroma. What is the most appropriate definitive management?

. Curettage and bone grafting
. Curettage with liquid nitrogen cryotherapy and cementation
. Wide surgical resection
. Primary radiation therapy
. Chemotherapy followed by en bloc resection

Correct Answer & Explanation

. Wide surgical resection

Explanation

The clinical, radiographic, and histological findings describe an adamantinoma, a low-grade malignant bone tumor that almost exclusively occurs in the anterior tibial cortex. It does not respond well to radiation or chemotherapy. The standard treatment is wide surgical resection to prevent local recurrence.

Question 2449

Topic: 10. Pathology and Oncology

A 15-year-old male undergoes neoadjuvant chemotherapy followed by wide resection of an osteosarcoma of the distal femur. Histopathologic analysis of the resected tumor specimen is performed. Which of the following findings is considered the single most important prognostic factor for long-term survival in this patient?

. Initial tumor volume greater than 100 mL
. Presence of a skip metastasis in the same bone
. Percentage of tumor necrosis induced by chemotherapy
. Positive surgical margins
. Alkaline phosphatase level at the time of diagnosis

Correct Answer & Explanation

. Percentage of tumor necrosis induced by chemotherapy

Explanation

The percentage of tumor necrosis following neoadjuvant chemotherapy (evaluated by mapping the resected specimen, classically graded by the Huvos system) is the most significant prognostic factor for long-term survival in conventional osteosarcoma. A good response is defined as >90% necrosis. While margins and skip lesions are important, tumor necrosis percentage is the classic primary prognostic indicator evaluated post-resection.

Question 2450

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in the diaphysis of his left femur. Radiographs reveal a permeative, destructive lesion with an onion-skin periosteal reaction. A biopsy is performed, and molecular pathology identifies a specific chromosomal translocation. Which translocation is most diagnostic for this neoplasm?

. 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. The t(11;22)(q24;q12) translocation is present in approximately 85% of Ewing sarcomas, resulting in the EWS-FLI1 fusion gene. t(X;18) is associated with synovial sarcoma; t(12;16) with myxoid liposarcoma; t(2;13) with alveolar rhabdomyosarcoma; and t(9;22) is the Philadelphia chromosome (CML).

Question 2451

Topic: 10. Pathology and Oncology

A 14-year-old boy completes neoadjuvant chemotherapy and undergoes surgical resection for a non-metastatic osteosarcoma of the distal femur. What is the most important prognostic factor for his long-term survival?

. The initial tumor size at presentation
. The histologic subtype of the osteosarcoma
. The percentage of tumor necrosis observed in the resected specimen
. The type of definitive surgical resection (amputation vs. limb salvage)
. Patient age and gender

Correct Answer & Explanation

. The percentage of tumor necrosis observed in the resected specimen

Explanation

The most significant prognostic factor for long-term survival in patients with non-metastatic osteosarcoma is the histologic response to neoadjuvant chemotherapy, defined by the percentage of tumor necrosis in the resected specimen. Greater than 90% necrosis identifies 'good responders' and is associated with significantly better outcomes.

Question 2452

Topic: 10. Pathology and Oncology

A 12-year-old presents with a diaphyseal bone lesion. Biopsy reveals sheets of small, round, blue cells with CD99 positivity. Cytogenetic analysis is ordered. Which of the following chromosomal translocations is most characteristic of this malignancy?

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

Correct Answer & Explanation

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

Explanation

The presentation is classic for Ewing Sarcoma. The hallmark cytogenetic abnormality for Ewing Sarcoma is the t(11;22)(q24;q12) translocation, which creates the EWS-FLI1 fusion gene. t(X;18) is seen in Synovial Sarcoma. t(2;13) is seen in Alveolar Rhabdomyosarcoma. t(12;16) is seen in Myxoid Liposarcoma. t(9;22) is the Philadelphia chromosome seen in CML.

Question 2453

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 is performed. Which of the following chromosomal translocations is most characteristic of this tumor?

. t(11;22)(q24;q12)
. t(X;18)(p11;q11)
. 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, resulting in the EWS-FLI1 fusion protein. Translocation t(X;18) is seen in synovial sarcoma; t(12;16) in myxoid liposarcoma; t(2;13) in alveolar rhabdomyosarcoma.

Question 2454

Topic: Bone Tumors

A 22-year-old male presents with dull, aching pain in his posterior thoracic spine that is not reliably relieved by NSAIDs. Radiographs and a CT scan reveal a 2.5 cm radiolucent nidus in the right lamina of T8 with surrounding sclerosis. What is the most likely diagnosis?

. Osteoid osteoma
. Osteoblastoma
. Aneurysmal bone cyst
. Giant cell tumor
. Eosinophilic granuloma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Both osteoid osteoma and osteoblastoma have similar histologic appearances (woven bone, prominent osteoblasts), but they are differentiated primarily by size and clinical presentation. Osteoblastomas are typically > 2 cm (often > 1.5-2.0 cm threshold used), locate commonly in the posterior elements of the spine, and cause dull aching pain that is less likely to have dramatic relief with NSAIDs/aspirin compared to osteoid osteoma (which is < 1.5 cm and classically features severe nocturnal pain dramatically relieved by NSAIDs).

Question 2455

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic shoulder pain and a lytic lesion in the proximal humeral epiphysis. Radiographs show a well-defined geographic lytic lesion with central punctate calcifications. Histological examination reveals sheets of cells with abundant clear cytoplasm, distinct cell membranes, and areas of malignant hyaline cartilage intermixed with woven bone. What is the most likely diagnosis?

. Chondroblastoma
. Giant Cell Tumor
. Clear cell chondrosarcoma
. Ewing sarcoma
. Osteoblastoma

Correct Answer & Explanation

. Clear cell chondrosarcoma

Explanation

Clear cell chondrosarcoma is a rare, low-grade variant of chondrosarcoma that characteristically occurs in the epiphysis of long bones (typically proximal femur or humerus) in adults (third to fifth decade). It often mimics chondroblastoma radiographically (which also occurs in the epiphysis but usually in younger patients prior to physeal closure), but histologically features cells with clear cytoplasm and malignant hyaline cartilage.

Question 2456

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slow-growing, painful mass in his left tibial diaphysis. Radiographs show a distinct, multi-loculated, expansile osteolytic 'soap-bubble' lesion within the anterior cortex of the tibia. Biopsy demonstrates a biphasic tumor with nests of basaloid epithelial cells dispersed within a fibrous stroma. What is the most appropriate definitive management for this lesion?

. Curettage and bone grafting
. Preoperative chemotherapy followed by wide resection
. Wide surgical resection
. Radiation therapy
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

The clinical, radiographic, and histologic presentation is classic for adamantinoma. Adamantinoma is a rare, low-grade malignant bone tumor that almost exclusively occurs in the anterior diaphyseal cortex of the tibia. It is biphasic, displaying both epithelial and osteofibrous components. It is notoriously resistant to both chemotherapy and radiation. The standard of care is wide surgical resection.

Question 2457

Topic: 10. Pathology and Oncology

Which of the following is the most significant adverse prognostic factor for overall survival in a patient with conventional high-grade osteosarcoma?

. High alkaline phosphatase at presentation
. Male gender
. Presence of skip metastases
. Tumor size greater than 8 cm
. Proximal tibial location

Correct Answer & Explanation

. Presence of skip metastases

Explanation

While high serum alkaline phosphatase and large tumor size are poor prognostic factors, the presence of macroscopic metastases (including skip lesions within the same bone or distant pulmonary metastases) is the most significant adverse prognostic indicator for overall survival in osteosarcoma.

Question 2458

Topic: 10. Pathology and Oncology

A 45-year-old patient presents with a painful cartilaginous lesion in the proximal femur. Which of the following histological features most reliably differentiates a low-grade (Grade 1) chondrosarcoma from a benign enchondroma?

. Presence of a cartilaginous matrix
. Binucleated chondrocytes
. Permeation and entrapment of host trabecular bone
. Myxoid degeneration of the stroma
. Lobular growth pattern

Correct Answer & Explanation

. Permeation and entrapment of host trabecular bone

Explanation

Distinguishing enchondroma from low-grade chondrosarcoma can be challenging. The most reliable histological feature of low-grade chondrosarcoma is its infiltrative growth pattern, demonstrating permeation of the marrow space and entrapment of pre-existing host lamellar bone trabeculae.

Question 2459

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in his diaphyseal femur. Biopsy reveals sheets of small round blue cells. Molecular testing of the tumor tissue is most likely to reveal which of the following chromosomal translocations?

. t(11;22)(q24;q12)
. t(X;18)(p11;q11)
. 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 presentation is classic for Ewing sarcoma. Over 90% of Ewing sarcomas are characterized by the t(11;22)(q24;q12) translocation, which results in the fusion of the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11. t(X;18) is seen in synovial sarcoma; t(12;16) in myxoid liposarcoma; t(2;13) in alveolar rhabdomyosarcoma; and t(9;22) in chronic myelogenous leukemia.

Question 2460

Topic: Bone Tumors

In evaluating a 16-year-old male with a newly diagnosed conventional high-grade osteosarcoma of the distal femur, appropriate staging studies are obtained. Among standard laboratory values, which of the following is considered an independent poor prognostic indicator for overall survival?

. Elevated serum calcium
. Elevated serum alkaline phosphatase (ALP)
. Decreased serum phosphorus
. Elevated C-reactive protein (CRP)
. Elevated serum uric acid

Correct Answer & Explanation

. Elevated serum alkaline phosphatase (ALP)

Explanation

In the staging and risk stratification of osteosarcoma, elevated levels of serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) at the time of diagnosis have been consistently shown in large cooperative group studies (like the European Osteosarcoma Intergroup) to be independent adverse prognostic factors, correlating with a higher risk of metastasis and poorer overall survival.

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