Menu

10. Pathology and Oncology MCQs

Practice Set 120 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 2381

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a diaphyseal femur lesion with an 'onion skin' periosteal reaction. A biopsy is performed, and cytogenetic analysis reveals a t(11;22)(q24;q12) translocation. Which of the following fusion products is most characteristic of this tumor?

. SYT-SSX1
. PAX3-FOXO1
. TLS-CHOP
. EWS-FLI1
. COL1A1-PDGFB

Correct Answer & Explanation

. EWS-FLI1

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. The t(11;22)(q24;q12) translocation is present in approximately 85% of cases and results in the EWS-FLI1 fusion protein. SYT-SSX is associated with synovial sarcoma; PAX3-FOXO1 is alveolar rhabdomyosarcoma; TLS-CHOP is myxoid liposarcoma; COL1A1-PDGFB is dermatofibrosarcoma protuberans.

Question 2382

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a destructive, lytic metaphyseal lesion of the distal femur. Biopsy shows blood-filled cystic spaces separated by septae. The septae contain highly pleomorphic stromal cells producing delicate lace-like osteoid. What is the most likely diagnosis?

. Aneurysmal bone cyst
. Telangiectatic osteosarcoma
. Giant cell tumor
. Chondroblastoma
. Ewing sarcoma

Correct Answer & Explanation

. Telangiectatic osteosarcoma

Explanation

Telangiectatic osteosarcoma mimics aneurysmal bone cysts (ABC) radiographically and grossly (blood-filled spaces). The distinguishing feature is the presence of malignant, highly pleomorphic, osteoid-producing cells in the septae. An ABC contains benign myofibroblasts and multinucleated giant cells without malignant osteoid.

Question 2383

Topic: 10. Pathology and Oncology

A 65-year-old male presents with back pain and a pathological fracture of L2. Laboratory workup reveals hypercalcemia, renal insufficiency, and anemia. Serum protein electrophoresis shows an M-spike. Which of the following is the most definitive diagnostic test to confirm multiple myeloma?

. Skeletal survey
. Bone marrow biopsy demonstrating >10% clonal plasma cells
. Urine immunofixation showing Bence Jones proteins
. MRI of the spine showing multiple lytic lesions
. Elevated beta-2 microglobulin levels

Correct Answer & Explanation

. Bone marrow biopsy demonstrating >10% clonal plasma cells

Explanation

The definitive diagnosis of multiple myeloma requires a bone marrow biopsy showing >10% clonal plasma cells (or a biopsy-proven bony/extramedullary plasmacytoma) along with myeloma-defining events such as end-organ damage (CRAB criteria: hypercalcemia, renal failure, anemia, bone lesions).

Question 2384

Topic: 10. Pathology and Oncology

A 14-year-old girl is diagnosed with high-grade conventional osteosarcoma of the distal femur. She completes a course of neoadjuvant chemotherapy followed by wide surgical resection. Which of the following factors determined from the resected specimen is the most important prognostic indicator for overall survival?

. The absolute size of the initial tumor
. The distance of the closest surgical margin
. The percentage of tumor necrosis
. The presence of skip metastases in the medullary canal
. The histologic subtype (e.g., chondroblastic vs. fibroblastic)

Correct Answer & Explanation

. The percentage of tumor necrosis

Explanation

In the treatment of conventional high-grade osteosarcoma, the degree of tumor necrosis in the resected specimen following neoadjuvant chemotherapy (the histologic response) is the single most important prognostic factor for long-term survival. A good response is typically defined as >= 90% tumor necrosis (Huvos grading system).

Question 2385

Topic: Bone Tumors

A 25-year-old male presents with chronic, dull posterior knee pain. Radiographs show a heavily ossified, lobulated mass attached by a broad base to the posterior cortex of the distal femur. MRI confirms no medullary involvement. Biopsy reveals a low-grade spindle cell stroma with well-formed woven bone trabeculae. What is the most likely diagnosis and its general prognosis compared to conventional osteosarcoma?

. Parosteal osteosarcoma; better prognosis
. Periosteal osteosarcoma; better prognosis
. High-grade surface osteosarcoma; worse prognosis
. Parosteal osteosarcoma; worse prognosis
. Periosteal osteosarcoma; worse prognosis

Correct Answer & Explanation

. Parosteal osteosarcoma; better prognosis

Explanation

Parosteal osteosarcoma is a low-grade surface osteosarcoma that classically arises from the posterior aspect of the distal femur. It typically presents as a heavily ossified, broad-based mass with no medullary involvement in its early stages. It has a significantly better prognosis than conventional high-grade intramedullary osteosarcoma. Periosteal osteosarcoma is intermediate-grade, chondroblastic, and more commonly affects the anterior tibia.

Question 2386

Topic: Bone Tumors

What specific genetic mutation is strongly associated with the pathogenesis of multiple enchondromatosis (Ollier disease and Maffucci syndrome)?

. EXT1 / EXT2
. GNAS1
. IDH1 / IDH2
. RUNX2
. COL1A1

Correct Answer & Explanation

. IDH1 / IDH2

Explanation

Somatic mosaic mutations in the isocitrate dehydrogenase (IDH1 and IDH2) genes are the primary drivers of Ollier disease and Maffucci syndrome. EXT1/EXT2 mutations are associated with Multiple Hereditary Exostoses. GNAS1 mutations are linked to fibrous dysplasia (McCune-Albright syndrome). RUNX2 is associated with cleidocranial dysplasia, and COL1A1 with osteogenesis imperfecta.

Question 2387

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic shoulder pain. Radiographs reveal a lytic lesion in the proximal humeral epiphysis. Biopsy demonstrates abundant clear cytoplasm, centrally located nuclei, and areas of conventional chondrosarcoma intimately associated with woven bone trabeculae. Immunohistochemistry is positive for S-100. Which of the following is the most likely diagnosis?

. Chondroblastoma
. Giant cell tumor
. Clear cell chondrosarcoma
. Osteoblastoma
. Aneurysmal bone cyst

Correct Answer & Explanation

. Clear cell chondrosarcoma

Explanation

Clear cell chondrosarcoma is a low-grade malignant cartilage tumor that typically occurs in the epiphysis of long bones (most commonly the proximal femur and humerus) in patients in their 3rd to 5th decades. It is distinguished from chondroblastoma, which also occurs in the epiphysis but usually in younger, skeletally immature patients, and has a different histologic profile (chicken-wire calcification, coffee-bean nuclei).

Question 2388

Topic: 10. Pathology and Oncology

A 24-year-old female presents with a deep, slow-growing, painful mass in her popliteal fossa. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Molecular testing is ordered. Which of the following chromosomal translocations is pathognomonic for this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The clinical picture and biphasic histology describe a synovial sarcoma. The characteristic cytogenetic abnormality found in >90% of synovial sarcomas is the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene.

Question 2389

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a diaphyseal femur lesion showing an 'onion skin' periosteal reaction. A biopsy confirms a small round blue cell tumor. Which of the following cytogenetic abnormalities is most diagnostic of this condition?

. t(X;18)(p11;q11)
. t(11;22)(q24;q12)
. t(9;22)(q22;q12)
. t(12;16)(q13;p11)
. MDM2 gene amplification

Correct Answer & Explanation

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

Explanation

Ewing sarcoma is characterized by 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; and MDM2 amplification with Parosteal/Low-grade central osteosarcoma.

Question 2390

Topic: Bone Tumors

A 55-year-old man undergoes resection of a large cartilaginous tumor of the proximal femur. Histopathology reveals abundant hyaline cartilage with hypercellularity, binucleate cells, and myxoid changes without osteoid matrix production. Which genetic mutation is most frequently associated with this primary bone malignancy?

. RUNX2 mutation
. IDH1 or IDH2 mutation
. TP53 mutation
. EXT1 or EXT2 mutation
. RB1 gene deletion

Correct Answer & Explanation

. IDH1 or IDH2 mutation

Explanation

The histopathology describes a primary chondrosarcoma. Mutations in IDH1 and IDH2 (Isocitrate Dehydrogenase) are found in up to 50-60% of central chondrosarcomas. EXT1/EXT2 are associated with osteochondromas.

Question 2391

Topic: 10. Pathology and Oncology

Mutations in the IDH1 and IDH2 genes are most characteristic of which of the following primary bone tumors?

. Osteosarcoma
. Ewing sarcoma
. Chondrosarcoma
. Giant cell tumor of bone
. Chordoma

Correct Answer & Explanation

. Chondrosarcoma

Explanation

Isocitrate dehydrogenase (IDH) 1 and 2 mutations are found in a high percentage of central enchondromas and conventional central chondrosarcomas. These mutations result in the production of the oncometabolite D-2-hydroxyglutarate.

Question 2392

Topic: 10. Pathology and Oncology

A 62-year-old female with breast cancer presents with a metastatic lesion in her femur. According to Mirels' criteria, which combination of factors yields the highest score, strongly indicating the need for prophylactic internal fixation?

. Upper extremity, blastic lesion, <1/3 cortical diameter, mild pain
. Lower extremity, blastic lesion, 1/3-2/3 cortical diameter, moderate pain
. Upper extremity, mixed lesion, >2/3 cortical diameter, moderate pain
. Lower extremity, lytic lesion, >2/3 cortical diameter, severe pain
. Peritrochanteric region, lytic lesion, <1/3 cortical diameter, mild pain

Correct Answer & Explanation

. Lower extremity, lytic lesion, >2/3 cortical diameter, severe pain

Explanation

Mirels' scoring system evaluates the risk of pathologic fracture based on four criteria: Site (upper extremity=1, lower extremity=2, peritrochanteric=3), Pain (mild=1, moderate=2, severe=3), Lesion character (blastic=1, mixed=2, lytic=3), and Size (<1/3=1, 1/3-2/3=2, >2/3=3). Option D (Lower extremity [2], lytic [3], >2/3 [3], severe pain [3]) yields a score of 11. A score of 9 or greater strongly recommends prophylactic fixation.

Question 2393

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic shoulder pain. Radiographs reveal a lytic lesion in the proximal humeral epiphysis with a sclerotic margin. Biopsy shows large cells with abundant clear cytoplasm and central nuclei, interspersed among woven bone. What is the most appropriate management?

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

Correct Answer & Explanation

. Wide surgical resection

Explanation

Clear cell chondrosarcoma typically presents in the epiphysis of long bones (proximal humerus/femur) in young adults (20-50 yrs). Histology shows characteristic clear cells. It is a low-grade malignant bone tumor. Because intralesional curettage leads to high recurrence rates, and it is resistant to chemotherapy and radiation, wide surgical resection is the standard of care.

Question 2394

Topic: 10. Pathology and Oncology

A 25-year-old male presents with chronic, dull pain in his anterior leg. Radiographs demonstrate a multiloculated, expansile, eccentric, mixed lytic-sclerotic lesion in the anterior cortex of the tibial diaphysis. Biopsy reveals islands of epithelial cells in a fibrous stroma. What is the best treatment for this lesion?

. Intralesional curettage and bone grafting
. Wide surgical resection and limb reconstruction
. Chemotherapy followed by intralesional curettage
. Primary amputation
. External beam radiation therapy

Correct Answer & Explanation

. Wide surgical resection and limb reconstruction

Explanation

The clinical, radiographic, and histologic presentation (epithelial cells in fibrous stroma) is classic for an adamantinoma. This is a rare, low-grade malignant bone tumor that almost exclusively occurs in the anterior tibial diaphysis. Because it is malignant and resistant to radiation and chemotherapy, the standard of care is wide surgical resection with limb-salvage reconstruction.

Question 2395

Topic: 10. Pathology and Oncology

A 25-year-old female presents with a painless, slow-growing mass on the posterior aspect of her distal femur. Radiographs show a dense, ossified mass attached to the cortex by a broad base, with a thin radiolucent cleft between the tumor and the underlying bone (string sign). Histopathology reveals low-grade spindle cells with woven bone. What is the most characteristic genetic alteration associated with this tumor?

. t(11;22) EWSR1-FLI1
. t(X;18) SYT-SSX
. MDM2 and CDK4 gene amplification
. H3F3A mutation
. EXT1 and EXT2 mutations

Correct Answer & Explanation

. MDM2 and CDK4 gene amplification

Explanation

The clinical and radiographic presentation describes a parosteal osteosarcoma, a low-grade surface osteosarcoma. The 'string sign' is classic on imaging. At the molecular level, parosteal osteosarcomas are characterized by supernumerary ring chromosomes leading to the amplification of MDM2 and CDK4 genes (12q13-15). t(11;22) is seen in Ewing sarcoma, t(X;18) in synovial sarcoma, H3F3A in giant cell tumors/chondroblastoma, and EXT1/2 in osteochondromas.

Question 2396

Topic: 10. Pathology and Oncology

A 65-year-old female with multiple myeloma is evaluated for prophylactic fixation of an impending pathologic fracture. According to Mirels' criteria, which of the following combinations of clinical and radiographic findings yields the highest score, heavily indicating the need for prophylactic internal fixation?

. Upper limb, blastic lesion, <1/3 cortex diameter
. Lower limb, mixed lesion, 1/3-2/3 cortex diameter
. Peritrochanteric region, lytic lesion, >2/3 cortex diameter
. Spine, mixed lesion, >2/3 cortex diameter
. Upper limb, lytic lesion, <1/3 cortex diameter

Correct Answer & Explanation

. Peritrochanteric region, lytic lesion, >2/3 cortex diameter

Explanation

Mirels' criteria scores four variables (1-3 points each): Site (Upper limb=1, Lower limb=2, Peritrochanteric=3), Nature (Blastic=1, Mixed=2, Lytic=3), Size (<1/3=1, 1/3-2/3=2, >2/3=3), and Pain (Mild=1, Mod=2, Functional=3). Option C represents Peritrochanteric (3) + Lytic (3) + >2/3 (3) = 9 points (excluding pain), strongly recommending prophylactic fixation (score >8 is an indication).

Question 2397

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with knee pain. MRI shows an expansile, multi-cystic lesion in the distal femur metaphysis with multiple fluid-fluid levels. Core needle biopsy reveals blood-filled spaces. Which histologic feature most reliably differentiates telangiectatic osteosarcoma from an aneurysmal bone cyst (ABC) in this setting?

. Presence of fluid-fluid levels on MRI
. Cellular atypia and pleomorphism in the septal stromal cells
. Presence of multinucleated giant cells
. Location of the lesion in the metaphysis
. A high presence of reactive woven bone

Correct Answer & Explanation

. Cellular atypia and pleomorphism in the septal stromal cells

Explanation

Both ABCs and telangiectatic osteosarcomas can present as expansile lytic lesions with fluid-fluid levels on MRI. The key distinguishing feature is histology: telangiectatic osteosarcoma exhibits malignant, highly pleomorphic stromal cells with atypical mitoses and malignant osteoid in the septa, whereas the septa in an ABC contain benign cells.

Question 2398

Topic: 10. Pathology and Oncology

A 15-year-old male presents with a painful, swollen mass in his proximal humerus. Biopsy demonstrates uniform, small blue round cells with PAS-positive cytoplasmic glycogen. Genetic analysis is requested to confirm the diagnosis. Which of the following chromosomal translocations is most characteristic of Ewing sarcoma?

. 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

Ewing sarcoma is characterized by 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(2;13) with alveolar rhabdomyosarcoma; and t(9;22) is the Philadelphia chromosome seen in CML.

Question 2399

Topic: 10. Pathology and Oncology
In a patient diagnosed with high-grade intramedullary osteosarcoma, which of the following factors is considered the most significant prognostic indicator for long-term survival?
. The initial size of the tumor
. The anatomic location of the tumor
. The histologic subtype (e.g., osteoblastic vs chondroblastic)
. The percentage of tumor necrosis following neoadjuvant chemotherapy
. The patient's age at diagnosis

Correct Answer & Explanation

. The percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The percentage of tumor necrosis following neoadjuvant chemotherapy is the most critical prognostic factor for overall survival in high-grade osteosarcoma. A good response is typically defined as >= 90% tumor necrosis (Huvos grade III or IV).

Question 2400

Topic: 10. Pathology and Oncology

A 16-year-old male undergoes wide surgical resection for a conventional high-grade osteosarcoma of the distal femur following a course of neoadjuvant chemotherapy. Pathologic analysis of the resected specimen reveals 95% tumor necrosis. This histological finding is the most reliable predictor for which of the following?

. High likelihood of local recurrence
. Development of secondary leukemia
. Improved overall survival
. Progression to skip metastases
. Resistance to future methotrexate therapy

Correct Answer & Explanation

. Improved overall survival

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for overall survival in patients with osteosarcoma. A necrosis rate of > 90% is classified as a 'good response' and is correlated with significantly improved overall survival.

Test Yourself

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

On this Page