Menu

10. Pathology and Oncology MCQs

Practice Set 321 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 6401

Topic: 10. Pathology and Oncology

A 55-year-old male presents with deep pelvic pain. Imaging reveals a large, lobulated soft tissue mass arising from the ilium with internal "ring and arc" calcifications and cortical breakthrough. Biopsy confirms Grade II conventional chondrosarcoma. What is the treatment of choice?

. Neoadjuvant chemotherapy followed by wide resection
. Radiation therapy alone
. Wide surgical resection
. Intralesional curettage with local adjuvants
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

Conventional chondrosarcoma is notably resistant to both chemotherapy and radiation therapy due to its poor vascularity and slow growth fraction. The mainstay of treatment is wide surgical resection with negative margins.

Question 6402

Topic: 10. Pathology and Oncology

A 40-year-old male with severe hemophilia B presents with an enlarging, painless mass in his right ilium. Radiographs show a large, expansile lytic lesion destroying the cortex, with an associated soft-tissue mass. Biopsy is contraindicated. What is the most likely diagnosis?

. Osteosarcoma
. Ewing sarcoma
. Hemophilic pseudotumor
. Brown tumor of hyperparathyroidism
. Aneurysmal bone cyst

Correct Answer & Explanation

. Hemophilic pseudotumor

Explanation

A hemophilic pseudotumor is an encapsulated hematoma caused by repeated intraosseous or subperiosteal bleeding, often presenting as a destructive, expansile lytic lesion on imaging. Biopsy can lead to uncontrollable hemorrhage or chronic fistulae and must be avoided.

Question 6403

Topic: Bone Tumors

An 11-year-old girl presents with fever, elevated ESR, and a painful thigh. Radiographs demonstrate a permeative, diaphyseal lytic lesion in the femur with a multilamellated ("onion skin") periosteal reaction. Cytogenetic testing reveals a t(11;22) translocation. Which fusion protein is produced by this translocation?

. EWS-FLI1
. SYT-SSX1
. PAX3-FOXO1
. TLS-CHOP
. BCR-ABL

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) chromosomal translocation in >85% of cases. This results in the EWS-FLI1 fusion protein, which acts as an aberrant transcription factor driving oncogenesis.

Question 6404

Topic: 10. Pathology and Oncology

A 22-year-old male presents with progressive, dull back pain that is not completely relieved by NSAIDs. Imaging reveals an expansile, 2.5 cm lytic lesion involving the posterior elements of the L4 vertebra with cortical thinning. Biopsy shows interconnected woven bone trabeculae lined by prominent osteoblasts in a vascular stroma. What distinguishes this lesion from an osteoid osteoma?

. Malignant transformation rate of 15%
. Presence of a t(11;22) translocation
. Size greater than 2 cm and unresponsiveness to NSAIDs
. Location strictly within the anterior vertebral body
. Presence of an abundant calcified chondroid matrix

Correct Answer & Explanation

. Size greater than 2 cm and unresponsiveness to NSAIDs

Explanation

Osteoblastomas are histologically identical to osteoid osteomas but are distinguished clinically by their larger size (>2 cm) and lack of dramatic pain relief with NSAIDs. They most commonly occur in the posterior elements of the spine and can be locally aggressive.

Question 6405

Topic: Bone Tumors

An 18-year-old male presents with persistent mid-thigh night pain that is reliably relieved by ibuprofen. Imaging shows a radiolucent nidus surrounded by reactive sclerosis.

If conservative management fails, what is the best next step in management?

. Amputation
. En bloc resection
. Radiofrequency ablation
. Curettage and bone grafting
. Primary radiation therapy

Correct Answer & Explanation

. Radiofrequency ablation

Explanation

Osteoid osteoma classically presents with night pain relieved by NSAIDs. Radiofrequency ablation is the gold standard minimally invasive surgical treatment when symptomatic management fails.

Question 6406

Topic: Bone Tumors

A 22-year-old male undergoes excision of a cortical bone lesion in his proximal femur. Histology reveals a highly vascularized nidus of woven bone surrounded by sclerotic cortical bone.

The central nidus typically produces high levels of which substance?

. Interleukin-1
. Prostaglandin E2
. Tumor necrosis factor alpha
. Vascular endothelial growth factor
. Bone morphogenetic protein 2

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteomas have a central nidus that produces high levels of Prostaglandin E2 (PGE2). This excess PGE2 production is the mechanism responsible for the intense local pain that is classically relieved by NSAIDs.

Question 6407

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a permeative lytic lesion in the femoral diaphysis with an associated onion-skin periosteal reaction. Biopsy shows uniform small round blue cells. Which chromosomal translocation is most characteristic of this diagnosis?

. 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

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation in 85% of cases. This results in the formation of the EWS-FLI1 fusion protein.

Question 6408

Topic: 10. Pathology and Oncology

Which of the following is the single most important prognostic factor for overall survival in a patient presenting with a high-grade intramedullary osteosarcoma?

. Patient age at diagnosis
. Tumor size
. Histologic subtype
. Presence of pulmonary metastases
. Extent of intra-articular involvement

Correct Answer & Explanation

. Presence of pulmonary metastases

Explanation

The presence of distant metastasis at the time of diagnosis is the most critical prognostic factor for overall survival in osteosarcoma patients. The lungs are the most common site of metastasis.

Question 6409

Topic: 10. Pathology and Oncology
A 25-year-old female sustains a subtrochanteric femur fracture through a benign-appearing ground-glass cystic lesion. She has a history of precocious puberty and large café-au-lait spots. Which of the following best describes the underlying pathophysiology?
. Disruption of normal type I collagen synthesis
. Defect in osteoclast-mediated bone resorption
. Gs-alpha protein mutation leading to increased cAMP
. FGFR3 mutation inhibiting chondrocyte proliferation
. Overexpression of RANKL

Correct Answer & Explanation

. Gs-alpha protein mutation leading to increased cAMP

Explanation

McCune-Albright syndrome consists of polyostotic fibrous dysplasia, precocious puberty, and café-au-lait spots. It is caused by a somatic activating mutation in the GNAS gene, leading to increased intracellular cAMP via the Gs-alpha protein.

Question 6410

Topic: 10. Pathology and Oncology

A 40-year-old male with severe Hemophilia A presents with an expanding, painless mass in the pelvis accompanied by osteolytic destruction of the ilium. What is the most appropriate initial management of this lesion?

. Immediate wide en bloc resection
. Core needle biopsy to rule out malignancy
. Factor replacement therapy and immobilization
. Radiation therapy
. Marginal excision

Correct Answer & Explanation

. Factor replacement therapy and immobilization

Explanation

Hemophilic pseudotumors are encapsulated hematomas causing pressure necrosis of adjacent bone. Initial management is prolonged factor replacement and immobilization; biopsy is strictly contraindicated due to bleeding risk.

Question 6411

Topic: Bone Tumors
A 65-year-old male presents with deep thigh pain. Radiographs reveal a lytic lesion in the proximal femur with endosteal scalloping >2/3 of cortical thickness and intralesional popcorn calcifications. What is the most appropriate definitive treatment for a conventional grade II lesion?
. Intralesional curettage and bone grafting
. Wide surgical resection
. Neoadjuvant chemotherapy followed by wide resection
. Primary radiation therapy
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

Conventional high-grade (Grade II or III) chondrosarcomas are largely resistant to chemotherapy and radiation. Wide surgical resection is the mainstay of treatment to prevent local recurrence.

Question 6412

Topic: Bone Tumors

A 14-year-old boy presents with worsening right thigh pain, typically at night, relieved by NSAIDs. An image is shown.

What is the classic radiolucent nidus size limit for this diagnosis?

. < 1.5 cm
. 1.5 - 3.0 cm
. > 3.0 cm
. > 5.0 cm
. > 10.0 cm

Correct Answer & Explanation

. < 1.5 cm

Explanation

Osteoid osteoma typically presents with nocturnal pain relieved by NSAIDs. The nidus is radiolucent and classically less than 1.5 cm in diameter. Lesions larger than this are considered osteoblastomas.

Question 6413

Topic: 10. Pathology and Oncology

A 12-year-old girl is evaluated for multiple bony prominences around her knees and wrists. Genetic testing reveals a mutation in the EXT1 gene. She is at highest risk for developing which of the following malignant tumors?

. Osteosarcoma
. Ewing sarcoma
. Secondary chondrosarcoma
. Malignificant fibrous histiocytoma
. Chondroblastoma

Correct Answer & Explanation

. Secondary chondrosarcoma

Explanation

Multiple Hereditary Exostoses (MHE) is an autosomal dominant condition linked to EXT1, EXT2, and EXT3 genes. Patients have a 1-5% lifetime risk of malignant transformation to a secondary chondrosarcoma, typically in adulthood.

Question 6414

Topic: Bone Tumors
A 9-year-old girl is found to have a "shepherd's crook" deformity of her proximal femur, café-au-lait spots with irregular "coast of Maine" borders, and precocious puberty. What is the underlying genetic mutation responsible for this triad?
. EXT1 mutation
. FGFR3 mutation
. GNAS1 somatic mutation
. COL1A1 mutation
. Runx2 mutation

Correct Answer & Explanation

. GNAS1 somatic mutation

Explanation

The clinical presentation is classic for McCune-Albright syndrome, which consists of polyostotic fibrous dysplasia, café-au-lait macules, and endocrine abnormalities. It is caused by a somatic, post-zygotic activating mutation in the GNAS1 gene.

Question 6415

Topic: Bone Tumors

A 16-year-old boy has an osteoid osteoma of the proximal tibia confirmed by imaging.

He has failed conservative management with NSAIDs. What is the current gold standard minimally invasive treatment for this lesion?

. Intralesional steroid injection
. Radiofrequency ablation (RFA)
. Cryotherapy
. Curettage and bone grafting
. En bloc resection

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

Radiofrequency ablation (RFA) under CT guidance has become the gold standard treatment for osteoid osteoma when medical management fails. It offers a high success rate, minimal morbidity, and rapid recovery compared to open surgical excision.

Question 6416

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain and a palpable mass. Radiographs show a "sunburst" periosteal reaction in the distal femur. Biopsy reveals malignant spindle cells producing osteoid. What is the most important prognostic factor for his long-term survival?

. Size of the primary tumor
. Extent of tumor necrosis following neoadjuvant chemotherapy
. Histologic subtype
. Preoperative alkaline phosphatase levels
. Location of the tumor

Correct Answer & Explanation

. Extent of tumor necrosis following neoadjuvant chemotherapy

Explanation

In conventional high-grade osteosarcoma, the degree of tumor necrosis (>90% indicates a good response) following neoadjuvant chemotherapy is the most critical prognostic factor for long-term survival.

Question 6417

Topic: 10. Pathology and Oncology

A 60-year-old man presents with dull pelvic pain. Pelvic radiograph reveals a large, ill-defined lytic lesion in the ilium with "popcorn" calcifications. Biopsy shows atypical chondrocytes in a hyaline cartilage matrix. What is the primary treatment for this condition?

. Primary radiotherapy
. Neoadjuvant chemotherapy followed by excision
. Wide surgical resection
. Denosumab therapy
. Intralesional curettage

Correct Answer & Explanation

. Wide surgical resection

Explanation

Conventional chondrosarcomas are characteristically resistant to both chemotherapy and radiotherapy. Therefore, wide surgical resection with negative margins is the primary and most effective treatment modality.

Question 6418

Topic: 10. Pathology and Oncology

A 10-year-old boy presents with fever, weight loss, and mid-shaft femur pain. Radiographs show an "onion-skin" periosteal reaction. Molecular testing of the biopsy specimen is expected to reveal which of the following chromosomal translocations?

. 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

Ewing sarcoma is a small round blue cell tumor that classically occurs in the diaphysis of long bones in children. It is characterized by the t(11;22)(q24;q12) translocation, which results in the EWS-FLI1 fusion protein.

Question 6419

Topic: 10. Pathology and Oncology

A 16-year-old boy has a painless, firm mass at the proximal medial tibia. Radiographs reveal a sessile bony outgrowth that is continuous with the medullary cavity of the underlying bone. When would surgical excision be definitively indicated?

. Diagnosis of the lesion before skeletal maturity
. Rapid growth or new onset of pain after skeletal maturity
. Cosmetic appearance of the bump
. Prophylaxis against malignant transformation in solitary lesions
. Patient is 12 years old

Correct Answer & Explanation

. Rapid growth or new onset of pain after skeletal maturity

Explanation

Osteochondromas are the most common benign bone tumors. Excision is indicated for mechanical symptoms, neurovascular compromise, or rapid growth/new pain after skeletal maturity, suggesting malignant transformation to chondrosarcoma.

Question 6420

Topic: Bone Tumors

A 20-year-old man underwent excision of a small bone lesion causing severe night pain.

Which of the following substances is produced in excess by the nidus, explaining the dramatic response to aspirin?

. Serotonin
. Prostaglandin E2 (PGE2)
. Histamine
. Substance P
. Interleukin-1

Correct Answer & Explanation

. Prostaglandin E2 (PGE2)

Explanation

The nidus of an osteoid osteoma produces high levels of Prostaglandin E2 (PGE2) due to increased COX-2 expression. This mediates the intense pain and explains the characteristic relief provided by NSAIDs and aspirin.

Test Yourself

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

On this Page