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10. Pathology and Oncology MCQs

Practice Set 328 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 6541

Topic: 10. Pathology and Oncology

A biopsy is obtained from a bony mass in the distal tibia of an 8-year-old boy. The pathologist reports that the histology is identical to an osteochondroma. Which of the following clinical or radiographic findings would definitively point to a diagnosis of Dysplasia Epiphysealis Hemimelica (DEH) rather than a standard osteochondroma?

. The presence of a cartilage cap
. The lesion arises from the metaphysis
. The lesion arises from the epiphysis
. The lesion is located in the upper limb
. The patient is female

Correct Answer & Explanation

. The lesion arises from the epiphysis

Explanation

Correct Answer: The lesion arises from the epiphysisWhile DEH and osteochondroma share identical histological features (including a cartilage cap), their anatomical origins differ. Osteochondromas arise from the metaphysis or diaphysis, whereas DEH arises exclusively from the epiphysis.

Question 6542

Topic: Bone Tumors

The imaging below shows a lesion localized on the lateral side of the talus. Histologically, this lesion is identical to an osteochondroma. What is the primary anatomical difference between this condition and a classic osteochondroma?


. This lesion arises from the diaphysis
. This lesion arises from the metaphysis
. This lesion arises from the epiphysis
. This lesion arises from the articular cartilage only
. This lesion arises from the joint capsule

Correct Answer & Explanation

. This lesion arises from the epiphysis

Explanation

Correct Answer: This lesion arises from the epiphysisThe imaging shows Dysplasia Epiphysealis Hemimelica (DEH) of the talus. Histologically, DEH is similar to an osteochondroma. However, the key distinguishing feature is that an osteochondroma arises from the metaphysis or diaphysis, whereas DEH arises directly from the epiphysis.

Question 6543

Topic: Bone Tumors

Dysplasia epiphysealis hemimelica (DEH) is characterized by asymmetric overgrowth. Which of the following best describes the typical radiographic appearance of DEH?

. Symmetrical epiphyseal enlargement with a single central ossification center
. Asymmetric epiphyseal enlargement with multiple ossification centers
. Metaphyseal flaring with a sunburst periosteal reaction
. Diaphyseal cortical thickening with a nidus
. Epiphyseal destruction with joint space narrowing

Correct Answer & Explanation

. Asymmetric epiphyseal enlargement with multiple ossification centers

Explanation

Correct Answer: Asymmetric epiphyseal enlargement with multiple ossification centersCharacteristically, DEH lesions show on radiographs as asymmetric epiphyseal enlargement with multiple ossification centers. This reflects the irregular, hemimelic overgrowth of the affected epiphysis.

Question 6544

Topic: 10. Pathology and Oncology

A patient presents with a protruding bone mass from the distal femoral epiphysis to the popliteal fossa, as seen in the sagittal MRI below. If a biopsy were performed on this mass, the histological findings would most closely resemble which of the following?


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

Correct Answer & Explanation

. Osteochondroma

Explanation

Correct Answer: OsteochondromaThe MRI shows DEH of the distal femur. Histologically, DEH is similar to an osteochondroma (featuring a cartilage cap over bony trabeculae). The main difference is anatomical origin: DEH arises from the epiphysis, whereas osteochondromas arise from the metaphysis or diaphysis.

Question 6545

Topic: Bone Tumors

A 9-year-old male presents with restricted ankle motion and a palpable hard mass. The imaging studies below are obtained. Based on the typical characteristics of the demonstrated pathology, which of the following best describes the expected histological findings?


. Proliferation of atypical chondrocytes with binucleation and myxoid stroma.
. Histologically identical to an osteochondroma but arising from the epiphysis.
. Sheets of small round blue cells with Homer-Wright rosettes.
. Woven bone trabeculae lined by prominent osteoblasts in a highly vascular stroma.
. Multinucleated giant cells interspersed with mononuclear stromal cells.

Correct Answer & Explanation

. Histologically identical to an osteochondroma but arising from the epiphysis.

Explanation

Correct Answer: BThe imaging shows Dysplasia Epiphysealis Hemimelica (DEH) localized on the lateral side of the talus. Histologically, DEH is indistinguishable from an osteochondroma. The critical differentiating factor is anatomical location: osteochondromas arise from the metaphysis or diaphysis, whereas DEH arises from the epiphysis.

Question 6546

Topic: Bone Tumors

A 7-year-old boy presents with a bony mass around the knee. Radiographs show an exostosis. The surgeon is differentiating between an osteochondroma and Dysplasia Epiphysealis Hemimelica (DEH). Which of the following features definitively distinguishes DEH from a classic osteochondroma?

. The presence of a cartilage cap
. The histological appearance of the chondrocytes
. The anatomical origin of the lesion from the epiphysis
. The male-to-female ratio of the affected patients
. The presence of aching pain and deformity

Correct Answer & Explanation

. The anatomical origin of the lesion from the epiphysis

Explanation

Correct Answer: CHistologically, DEH is similar or identical to an osteochondroma. The definitive distinguishing feature is the anatomical origin: an osteochondroma arises from the metaphysis or diaphysis, whereas DEH arises specifically from the epiphysis.

Question 6547

Topic: 10. Pathology and Oncology

A 6-year-old child is diagnosed with Dysplasia Epiphysealis Hemimelica of the ankle.

The parents inquire about the potential for malignant transformation of this lesion over the child's lifetime. What is the most accurate information to provide?

. There is a 10% risk of malignant transformation to chondrosarcoma.
. Malignant transformation is extremely rare and virtually nonexistent.
. The risk of malignancy increases significantly if the lesion is located in the axial skeleton.
. Malignant transformation is common if the mass is incompletely excised.
. The mass typically transforms into an osteosarcoma during the adolescent growth spurt.

Correct Answer & Explanation

. Malignant transformation is extremely rare and virtually nonexistent.

Explanation

Malignant transformation of DEH has almost never been reported in the literature. It is considered a benign developmental anomaly of epiphyseal cartilage overgrowth.

Question 6548

Topic: Bone Tumors

A 7-year-old boy presents with an enlarging mass on the medial aspect of his right foot and ankle.

He complains of a mechanical block to ankle dorsiflexion. Based on the pathogenesis of Dysplasia Epiphysealis Hemimelica, this lesion is histologically indistinguishable from which of the following bone tumors?

. Osteochondroma
. Chondroblastoma
. Osteoid osteoma
. Enchondroma
. Chondromyxoid fibroma

Correct Answer & Explanation

. Osteochondroma

Explanation

Histologically, DEH is identical to an osteochondroma, consisting of a hyaline cartilage cap overlying trabecular bone. The defining difference is its origin from the epiphysis or carpal/tarsal equivalents, rather than the metaphysis.

Question 6549

Topic: 10. Pathology and Oncology

A 4-year-old boy is scheduled for excision of a symptomatic epiphyseal lesion of the ankle.

The surgeon carefully plans to resect the overgrowth while protecting the normal epiphysis. What is the most common reason for recurrence following surgical excision of DEH?

. Malignant dedifferentiation
. Incomplete removal of the cartilage cap
. Failure to resect the underlying metaphysis
. Failure to perform an accompanying osteotomy
. Premature physeal closure

Correct Answer & Explanation

. Incomplete removal of the cartilage cap

Explanation

Similar to standard osteochondromas, recurrence of DEH after surgical excision is primarily due to incomplete removal of the cartilaginous cap. The active growing cells are located within this cap.

Question 6550

Topic: 10. Pathology and Oncology

A 3-year-old is being evaluated for a hard, asymmetrical swelling of the ankle. Magnetic Resonance Imaging (MRI) is ordered. What is the primary advantage of MRI over plain radiography in early stages of Dysplasia Epiphysealis Hemimelica?

. It can identify EXT1 mutations through spectroscopic analysis.
. It clearly visualizes the unossified cartilage cap and its exact relationship to the articular surface.
. It detects early malignant transformation with 100% sensitivity.
. It measures bone mineral density of the surrounding metaphysis.
. It visualizes the nidus to differentiate it from an osteoid osteoma.

Correct Answer & Explanation

. It clearly visualizes the unossified cartilage cap and its exact relationship to the articular surface.

Explanation

In young children, much of the epiphysis and the DEH lesion itself may be unossified cartilage. MRI is superior for delineating the extent of the unossified cartilage cap and evaluating joint congruity.

Question 6551

Topic: Bone Tumors

Which of the following clinical findings best distinguishes Dysplasia Epiphysealis Multiplex (Multiple Epiphyseal Dysplasia) from Dysplasia Epiphysealis Hemimelica?

. MED usually presents with an asymmetrical, unilateral hard mass.
. DEH is typically bilateral and symmetrical, affecting multiple joints equally.
. MED is characterized by bilateral, symmetrical epiphyseal abnormalities and short stature.
. DEH is invariably associated with spinal anomalies and kyphoscoliosis.
. MED lesions are histologically identical to osteochondromas.

Correct Answer & Explanation

. MED is characterized by bilateral, symmetrical epiphyseal abnormalities and short stature.

Explanation

Multiple Epiphyseal Dysplasia (MED) is a genetic disorder causing bilateral, symmetrical epiphyseal irregularities and short stature. In contrast, DEH is unilateral, localized to half a joint, and characterized by an exophytic osteocartilaginous mass.

Question 6552

Topic: Bone Tumors

When planning an excision for a symptomatic DEH lesion of the distal femur, which of the following describes the most significant challenge specific to this condition compared to a traditional metaphyseal osteochondroma?

. The DEH lesion has a very high rate of massive intraoperative hemorrhage.
. The DEH lesion lacks a distinct plane between the mass and normal articular cartilage.
. The DEH lesion is always intramedullary and requires unroofing of the cortex.
. The DEH lesion requires postoperative radiation to prevent recurrence.
. The DEH lesion usually surrounds major neurovascular bundles.

Correct Answer & Explanation

. The DEH lesion lacks a distinct plane between the mass and normal articular cartilage.

Explanation

Because DEH arises directly from the epiphysis, the mass often blends indistinguishably with the normal articular cartilage. Preserving the normal articular congruity while resecting the lesion is the primary surgical challenge.

Question 6553

Topic: 10. Pathology and Oncology

A 5-year-old boy presents with a hard mass on the lateral aspect of his ankle. Plain radiographs demonstrate an eccentric ossific mass adjacent to the lateral talar body. Which of the following conditions presents as an intra-epiphyseal lytic lesion rather than an exostotic mass, distinguishing it from DEH?

. Osteochondroma
. Chondroblastoma
. Aneurysmal bone cyst
. Non-ossifying fibroma
. Osteosarcoma

Correct Answer & Explanation

. Chondroblastoma

Explanation

Chondroblastoma is an intra-epiphyseal benign tumor that presents as a lytic lesion on radiographs. DEH, conversely, presents as an exophytic osteocartilaginous overgrowth (exostosis) arising from the epiphysis.

Question 6554

Topic: Bone Tumors

In evaluating a new patient with suspected DEH, which of the following systemic syndromic associations should the clinician screen for?

. Neurofibromatosis type 1
. McCune-Albright syndrome
. Multiple endocrine neoplasia
. No systemic syndromes, as DEH is typically an isolated finding
. Klippel-Trenaunay syndrome

Correct Answer & Explanation

. No systemic syndromes, as DEH is typically an isolated finding

Explanation

DEH (Trevor's disease) is typically an isolated developmental anomaly. It is not characteristically associated with any underlying systemic syndromes or known genetic cascades.

Question 6555

Topic: 10. Pathology and Oncology

A 4-year-old boy presents with a painless, hard swelling on the medial aspect of his ankle. Radiographs reveal irregular, multicentric opacities adjacent to the medial aspect of the talar epiphysis. Histological examination of a biopsy from the lesion would most likely reveal which of the following?

. A cartilage cap overlying trabecular bone
. Lobules of hyaline cartilage with dense calcification
. Sheets of uniform, small round blue cells
. Benign proliferation of the synovial lining
. Avascular necrotic bone with creeping substitution

Correct Answer & Explanation

. A cartilage cap overlying trabecular bone

Explanation

Dysplasia Epiphysealis Hemimelica (DEH), or Trevor's disease, is essentially an osteochondroma arising from the epiphysis. Its histology is identical to a classic metaphyseal osteochondroma, demonstrating a cartilage cap overlying normal trabecular bone.

Question 6556

Topic: 10. Pathology and Oncology

What is the fundamental pathophysiological mechanism underlying the development of Dysplasia Epiphysealis Hemimelica?

. Hyperplasia of the synovial membrane with metaplasia
. Disruption of metaphyseal bone remodeling
. Ectopic ossification of the joint capsule and ligaments
. Osteochondromatous overgrowth arising from the epiphysis or apophysis
. Malignant transformation of resting epiphyseal cartilage

Correct Answer & Explanation

. Osteochondromatous overgrowth arising from the epiphysis or apophysis

Explanation

DEH is caused by a localized, abnormal proliferation of epiphyseal osteochondromatous tissue. It represents a benign overgrowth of cartilage at the epiphysis that subsequently ossifies.

Question 6557

Topic: 10. Pathology and Oncology

Which of the following classification systems is utilized to describe the anatomical extent and multiplicity of lesions in Dysplasia Epiphysealis Hemimelica?

. Enneking system
. Azouz classification
. Campanacci grading
. Capanna classification
. MSTS staging

Correct Answer & Explanation

. Azouz classification

Explanation

The Azouz classification is used for DEH, dividing it into localized (single epiphysis), classic/regional (>1 epiphysis in one limb), and generalized (involvement of the entire lower limb).

Question 6558

Topic: 10. Pathology and Oncology

A 5-year-old child presents with a mass around the knee. Imaging reveals an epiphyseal bony outgrowth consistent with DEH. Which of the following is the most appropriate primary indication for surgical excision?

. The mere presence of the lesion on imaging
. High perceived risk of malignant transformation
. Presence of a mechanical joint block or progressive deformity
. Cosmetic concerns expressed by the parents
. The finding of an associated EXT mutation

Correct Answer & Explanation

. Presence of a mechanical joint block or progressive deformity

Explanation

Asymptomatic DEH lesions are observed. Surgical excision is indicated primarily when the mass causes a mechanical block to joint motion, pain, or a progressive angular deformity.

Question 6559

Topic: 10. Pathology and Oncology

A 6-year-old boy has an irregular, multi-centric ossification mass adjacent to the medial talar epiphysis.

According to the natural history of this condition, when is the progressive growth of the lesion expected to cease?

. At 10 years of age universally
. Following a diagnostic surgical biopsy
. At the time of skeletal maturity and physeal closure
. It grows continuously throughout the patient's adult life
. Following the administration of intravenous bisphosphonates

Correct Answer & Explanation

. At the time of skeletal maturity and physeal closure

Explanation

Similar to typical osteochondromas, the growth of a DEH lesion is tied to skeletal growth. The lesion will naturally stop enlarging once skeletal maturity is reached and the physes close.

Question 6560

Topic: Bone Tumors

In differentiating Dysplasia Epiphysealis Hemimelica (DEH) from Multiple Hereditary Exostoses (MHE), which of the following is a key distinguishing feature of DEH?

. The lesions predominantly arise from the diaphysis.
. It exhibits a strong autosomal dominant inheritance pattern.
. It carries a much higher rate of chondrosarcoma transformation.
. The lesions characteristically arise from the epiphysis or apophysis.
. It frequently presents with bilateral, symmetrical upper limb deformities.

Correct Answer & Explanation

. The lesions characteristically arise from the epiphysis or apophysis.

Explanation

MHE is characterized by multiple osteochondromas arising from the metaphysis, whereas DEH uniquely describes osteochondromas arising from the epiphysis or apophysis.

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