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10. Pathology and Oncology MCQs

Practice Set 166 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 3301

Topic: Bone Tumors

When evaluating plain radiographs of a patient with Dysplasia Epiphysealis Hemimelica (DEH), what is the classic radiographic hallmark of the lesion?

. Symmetrical enlargement of the entire epiphysis with a single central lucency
. Asymmetric epiphyseal enlargement with multiple ossification centers
. A purely lytic epiphyseal lesion with a sclerotic margin
. Sunburst periosteal reaction extending from the metaphysis

Correct Answer & Explanation

. Asymmetric epiphyseal enlargement with multiple ossification centers

Explanation

Correct Answer: Asymmetric epiphyseal enlargement with multiple ossification centersOn radiographs, DEH lesions characteristically show asymmetric epiphyseal enlargement (due to the hemimelic nature of the disease) accompanied by multiple ossification centers.

Question 3302

Topic: 10. Pathology and Oncology

A 7-year-old boy presents with the clinical finding shown below. If a biopsy of the underlying bony mass is performed, the histological appearance will most closely resemble which of the following benign bone tumors?




. Osteoid osteoma
. Osteochondroma
. Chondroblastoma
. Enchondroma
. Giant cell tumor

Correct Answer & Explanation

. Osteochondroma

Explanation

Correct Answer: OsteochondromaThe image demonstrates a moderate, painless, bone-hard swelling at the lateral side of the ankle, characteristic of Dysplasia Epiphysealis Hemimelica (DEH). Histologically, DEH lesions are similar to osteochondromas (featuring a cartilage cap over trabecular bone). The key distinguishing factor is their anatomical origin: osteochondromas arise from the metaphysis or diaphysis, whereas DEH arises from the epiphysis.

Question 3303

Topic: Bone Tumors

The imaging below demonstrates a protruding bone mass in a 10-year-old patient. Unlike a standard exostosis, this specific lesion originates from which anatomical region?




. Diaphysis
. Metaphysis
. Physis
. Epiphysis
. Apophysis

Correct Answer & Explanation

. Epiphysis

Explanation

Correct Answer: EpiphysisThe provided radiograph and MRI show a protruding bone mass extending into the popliteal fossa. This is a classic presentation of Dysplasia Epiphysealis Hemimelica (DEH). While histologically identical to an osteochondroma, DEH is defined by its origin from the epiphysis, whereas true osteochondromas arise from the metaphysis or diaphysis.

Question 3304

Topic: Bone Tumors

A 5-year-old boy undergoes excision of a bony mass causing a deformity at the medial aspect of the distal tibia. Histological examination reveals a cartilage-capped bony outgrowth. Which of the following features definitively distinguishes Dysplasia Epiphysealis Hemimelica from a solitary osteochondroma in this patient?

. The presence of a hyaline cartilage cap
. The continuity of the medullary cavity with the host bone
. The origin of the lesion from the epiphysis
. The presence of endochondral ossification
. The age of the patient

Correct Answer & Explanation

. The origin of the lesion from the epiphysis

Explanation

Correct Answer: The origin of the lesion from the epiphysisHistologically, DEH is indistinguishable from an osteochondroma. The definitive distinguishing feature is the anatomical site of origin: DEH arises from the epiphysis, whereas osteochondromas arise from the metaphysis or diaphysis.

Question 3305

Topic: Bone Tumors

A 6-year-old child is evaluated for a suspected skeletal developmental disorder affecting the epiphyses. Which of the following constellations of symptoms is most classically associated with the presentation of Dysplasia Epiphysealis Hemimelica?

. Painless hypermobility and recurrent dislocations
. Bone-hard mass, deformity, aching pains, and limited range of motion
. Night pain relieved by NSAIDs and a radiolucent nidus
. Rapidly growing soft tissue mass with overlying skin erythema
. Symmetrical polyarticular joint swelling and morning stiffness

Correct Answer & Explanation

. Bone-hard mass, deformity, aching pains, and limited range of motion

Explanation

Correct Answer: Bone-hard mass, deformity, aching pains, and limited range of motionThe most common presenting symptoms of Dysplasia Epiphysealis Hemimelica (DEH) include the presence of a mass with the consistency of bone, visible deformity, aching pains, and a limited range of motion in the affected joint.

Question 3306

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a posterior knee mass and limited flexion. Imaging is shown below. If a biopsy is taken from the protruding mass, the histological appearance will most closely resemble which of the following lesions?



. Osteoid osteoma
. Chondroblastoma
. Osteochondroma
. Enchondroma
. Giant cell tumor

Correct Answer & Explanation

. Osteochondroma

Explanation

Correct Answer: OsteochondromaThe imaging demonstrates a protruding bone mass from the distal femoral epiphysis into the popliteal fossa, typical of Dysplasia Epiphysealis Hemimelica (DEH). Histologically, the lesion is identical to an osteochondroma. The key differentiating factor is location: osteochondromas arise from the metaphysis or diaphysis, whereas DEH arises from the epiphysis.

Question 3307

Topic: Bone Tumors

Both Dysplasia Epiphysealis Hemimelica (DEH) and osteochondroma share similar histological features. Which of the following characteristics best differentiates DEH from a typical osteochondroma?

. DEH lacks a cartilage cap.
. DEH arises from the epiphysis, whereas osteochondroma arises from the metaphysis or diaphysis.
. DEH is typically a malignant precursor.
. Osteochondroma presents with multiple ossification centers within the joint space.
. DEH exclusively affects the upper limbs.

Correct Answer & Explanation

. DEH arises from the epiphysis, whereas osteochondroma arises from the metaphysis or diaphysis.

Explanation

Correct Answer: DEH arises from the epiphysis, whereas osteochondroma arises from the metaphysis or diaphysis.Histologically, DEH is similar to an osteochondroma (both have a cartilage cap and underlying trabecular bone). However, osteochondromas arise from the metaphysis or diaphysis, whereas DEH uniquely arises from the epiphysis, leading to intra-articular pathology and joint deformity.

Question 3308

Topic: 10. Pathology and Oncology

An 8-year-old male presents with asymmetric medial swelling of his left knee and a progressive varus deformity. Radiographs show a mass arising from the medial distal femoral epiphysis. If aggressive surgical excision is performed, what is the most significant long-term risk?

. Malignant transformation to chondrosarcoma
. Early onset secondary osteoarthritis
. Pathological fracture of the diaphysis
. Rapid systemic metastasis
. Spontaneous osteonecrosis of the femoral head

Correct Answer & Explanation

. Early onset secondary osteoarthritis

Explanation

Surgical excision of DEH risks damaging the normal articular cartilage and joint mechanics. This often leads to premature secondary osteoarthritis if the joint surface cannot be smoothly restored.

Question 3309

Topic: 10. Pathology and Oncology

Which of the following best describes the natural history of the lesions in Dysplasia Epiphysealis Hemimelica?

. They undergo spontaneous regression by adolescence
. They continue to grow aggressively throughout adulthood
. They stop enlarging once skeletal maturity is reached
. They invariably undergo malignant transformation in the third decade
. They detach to become intra-articular loose bodies

Correct Answer & Explanation

. They stop enlarging once skeletal maturity is reached

Explanation

The growth of DEH lesions parallels the growth of the child. Enlargement of the osteocartilaginous mass characteristically ceases at skeletal maturity.

Question 3310

Topic: Bone Tumors

A 4-year-old child presents with irregular, multi-centric radiopaque foci adjacent to the medial aspect of the distal tibial epiphysis on plain radiographs. Over the next two years, these foci are expected to:

. Migrate into the metaphysis
. Resorb completely without intervention
. Enlarge and merge with the main epiphyseal ossification center
. Penetrate the articular cartilage and cause a hemarthrosis
. Induce an adjacent osteosarcoma

Correct Answer & Explanation

. Enlarge and merge with the main epiphyseal ossification center

Explanation

Early radiographic findings of DEH include multiple irregular ossification centers adjacent to the epiphysis. Over time, these foci enlarge and coalesce into a single mass that merges with the native epiphysis.

Question 3311

Topic: 10. Pathology and Oncology

You evaluate a 6-year-old boy whose parents report a painless, hard swelling on the medial aspect of his ankle.

He has full range of motion and no deformity. What is the most appropriate management?

. Immediate en bloc resection
. Diagnostic core needle biopsy
. Observation and clinical monitoring
. Epiphysiodesis of the contralateral limb
. Intralesional steroid injection

Correct Answer & Explanation

. Observation and clinical monitoring

Explanation

Asymptomatic lesions of DEH that do not cause mechanical blocks, pain, or progressive deformity should be observed. Premature or unnecessary surgery carries a high risk of joint stiffness and iatrogenic degeneration.

Question 3312

Topic: Bone Tumors

Which of the following best describes the fundamental pathogenesis of Dysplasia Epiphysealis Hemimelica (Trevor disease)?

. Failure of primary spongiosa resorption
. Autosomal dominant mutation in EXT1
. Avascular necrosis of the secondary ossification center
. Proliferation of an epiphyseal osteochondroma
. Metaphyseal fibrous defect

Correct Answer & Explanation

. Proliferation of an epiphyseal osteochondroma

Explanation

Dysplasia Epiphysealis Hemimelica (DEH), or Trevor disease, is essentially an osteochondroma arising from the epiphysis. It results from an asymmetrical, hamartomatous proliferation of the epiphyseal cartilage.

Question 3313

Topic: Bone Tumors

Which of the following MRI findings is most characteristic of Dysplasia Epiphysealis Hemimelica and helps confirm the diagnosis preoperatively?

. High T1 signal indicating fatty marrow replacement
. Double-line sign pathognomonic for osteonecrosis
. A cartilage cap contiguous with the normal epiphyseal cartilage
. Disruption of the physis with a fibrous tether
. Intramedullary cystic lesion with fluid-fluid levels

Correct Answer & Explanation

. A cartilage cap contiguous with the normal epiphyseal cartilage

Explanation

MRI is crucial for evaluating DEH, demonstrating a hyperintense cartilage cap on T2-weighted images that is continuous with the normal articular cartilage of the epiphysis. This confirms its epiphyseal origin.

Question 3314

Topic: 10. Pathology and Oncology

A 5-year-old girl is diagnosed with DEH of the ankle. What is the primary indication for surgical excision in this patient?

. Mild cosmetic asymmetry
. Diagnosis confirmation in asymptomatic patients
. Prophylaxis against malignant transformation
. Mechanical block to joint range of motion
. Incidental finding on trauma radiograph

Correct Answer & Explanation

. Mechanical block to joint range of motion

Explanation

Asymptomatic DEH should be observed. Surgical excision is indicated primarily for pain, progressive deformity, or mechanical symptoms such as joint locking or restriction of motion.

Question 3315

Topic: Bone Tumors

A 5-year-old boy presents with an asymmetric valgus deformity of the right knee. MRI is performed to evaluate an irregular ossific mass adjacent to the medial condyle. What is the most characteristic MRI finding of this lesion?

. A fluid-filled cyst with a thick sclerotic rim
. An epiphyseal osteocartilaginous mass showing corticomedullary continuity with the underlying bone
. A diaphyseal intramedullary lesion with multiple fluid-fluid levels
. A hyperintense metaphyseal mass with punctate popcorn calcifications
. Subperiosteal reactive bone formation with a sunburst periosteal reaction

Correct Answer & Explanation

. An epiphyseal osteocartilaginous mass showing corticomedullary continuity with the underlying bone

Explanation

On MRI, DEH typically appears as an epiphyseal mass that demonstrates corticomedullary continuity with the host bone. This appearance mimics an osteochondroma, but it uniquely originates from the epiphysis.

Question 3316

Topic: 10. Pathology and Oncology

A parent of an 8-year-old child recently diagnosed with Dysplasia Epiphysealis Hemimelica asks about the risk of the lesion undergoing malignant transformation. What is the correct evidence-based counseling?

. The risk is approximately 10%, necessitating prophylactic excision
. The risk is significantly higher in upper extremity lesions
. Malignant transformation has not been well-documented and the risk is considered negligible
. The risk increases exponentially after skeletal maturity, requiring annual MRI surveillance
. The lesion is a low-grade chondrosarcoma variant and requires immediate wide resection

Correct Answer & Explanation

. Malignant transformation has not been well-documented and the risk is considered negligible

Explanation

DEH is a benign developmental disorder rather than a true neoplasm. Malignant transformation is extremely rare, with virtually no well-documented cases in the literature.

Question 3317

Topic: 10. Pathology and Oncology

Which of the following represents the most appropriate primary indication for surgical excision of a lesion in a patient with Dysplasia Epiphysealis Hemimelica?

. Incidental radiographic finding in an asymptomatic patient
. Prophylaxis against future malignant transformation
. Prevention or correction of progressive articular deformity and mechanical block
. Progression of the lesion to involve the contralateral extremity
. To obtain a definitive biopsy ruling out Ewing sarcoma

Correct Answer & Explanation

. Prevention or correction of progressive articular deformity and mechanical block

Explanation

Surgery for DEH is indicated for symptomatic patients to relieve pain, correct or prevent progressive joint deformity, and resolve mechanical blocks to motion. Asymptomatic lesions can be safely observed.

Question 3318

Topic: 10. Pathology and Oncology

In a patient with untreated Dysplasia Epiphysealis Hemimelica (Trevor disease) involving the ankle, which of the following secondary changes is most likely to develop due to chronic mechanical joint incongruity?

. Charcot neuroarthropathy
. Early-onset secondary osteoarthritis
. Avascular necrosis of the talus
. Spontaneous joint fusion (ankylosis)
. Malignant transformation to secondary chondrosarcoma

Correct Answer & Explanation

. Early-onset secondary osteoarthritis

Explanation

If left untreated, the intra-articular cartilaginous overgrowth in DEH causes a mechanical block and joint incongruity. Over time, this abnormal biomechanical wear leads to early-onset secondary osteoarthritis of the affected joint.

Question 3319

Topic: 10. Pathology and Oncology

Which of the following anatomical characteristics reliably differentiates Dysplasia Epiphysealis Hemimelica (DEH) from a typical solitary osteochondroma?

. DEH lacks a hyaline cartilage cap.
. DEH exhibits malignant features on histology.
. DEH originates from the epiphysis or epiphyseal equivalents.
. DEH originates from the diaphyseal cortex.
. DEH involves marked cortical destruction.

Correct Answer & Explanation

. DEH originates from the epiphysis or epiphyseal equivalents.

Explanation

While DEH and osteochondroma are histologically identical, DEH uniquely originates from the epiphysis or epiphyseal equivalents (like carpal and tarsal bones). Solitary osteochondromas typically arise from the metaphysis.

Question 3320

Topic: 10. Pathology and Oncology

A 25-year-old patient presents with severe knee pain and restricted range of motion. He was diagnosed with untreated Dysplasia Epiphysealis Hemimelica of the proximal tibia during childhood. What is the most likely long-term complication explaining his current symptoms?

. Malignant transformation to chondrosarcoma
. Pathologic fracture of the proximal tibia
. Early-onset secondary osteoarthritis
. Spontaneous intra-articular hemorrhage
. Avascular necrosis of the tibial plateau

Correct Answer & Explanation

. Early-onset secondary osteoarthritis

Explanation

Untreated DEH frequently leads to joint incongruity, mechanical block, and subsequent early-onset secondary osteoarthritis. Malignant transformation is exceedingly rare.

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