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Bone Tumors MCQs

Practice Set 48 of 52

This practice set contains high-yield board review questions covering key concepts in Bone Tumors. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 941

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 942

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 943

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 944

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 945

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 946

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 947

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.

Question 948

Topic: Bone Tumors

A 6-year-old child presents with a painless, restricted range of motion in the right ankle. An MRI is ordered to evaluate a suspected Dysplasia Epiphysealis Hemimelica (DEH) lesion of the talus. Which of the following MRI findings is most characteristic of this pathology?

. Continuity of the lesion's medullary cavity with the metaphyseal bone marrow.
. Continuity of the lesion's cartilage cap with the native epiphyseal cartilage.
. A radiolucent nidus surrounded by intense reactive sclerosis.
. Extensive soft tissue invasion crossing the joint space.
. A fluid-filled cystic lesion with multiple internal septations.

Correct Answer & Explanation

. Continuity of the lesion's cartilage cap with the native epiphyseal cartilage.

Explanation

On MRI, a DEH lesion demonstrates continuity of its cartilaginous cap with the native articular epiphyseal cartilage. This contrasts with an osteochondroma, which arises from the metaphysis and shows continuity with the metaphyseal medullary cavity.

Question 949

Topic: Bone Tumors

A 5-year-old boy undergoes an excisional biopsy of an irregular, hard mass protruding from the medial distal tibial epiphysis. The histopathology report indicates mature trabecular bone covered by a hyaline cartilage cap undergoing endochondral ossification. Based on these findings, how does the histology of Dysplasia Epiphysealis Hemimelica (DEH) compare to an osteochondroma?

. DEH features a significantly higher mitotic index in the cartilage cap.
. DEH contains multiple areas of woven bone without endochondral ossification.
. DEH is histologically indistinguishable from an osteochondroma.
. DEH lacks a distinct hyaline cartilage cap.
. DEH features characteristic giant cells and aneurysmal bone cysts.

Correct Answer & Explanation

. DEH is histologically indistinguishable from an osteochondroma.

Explanation

Histologically, DEH is identical to an osteochondroma, demonstrating mature bone covered by a hyaline cartilage cap undergoing endochondral ossification. The primary difference is anatomical location (epiphyseal in DEH vs. metaphyseal in osteochondroma).

Question 950

Topic: Bone Tumors

During a resident teaching round, the attending asks for the defining anatomical distinction between Multiple Hereditary Exostoses (MHE) and Dysplasia Epiphysealis Hemimelica (DEH). While both present with osteochondroma-like lesions, DEH is uniquely characterized by its origin from which specific region of the developing bone?

. Metaphysis
. Diaphysis
. Epiphysis
. Apophysis
. Perichondrial ring of LaCroix

Correct Answer & Explanation

. Epiphysis

Explanation

The hallmark of DEH (Trevor's disease) is the asymmetric overgrowth of cartilage arising directly from the epiphysis. In contrast, the lesions in MHE (osteochondromas) arise from the metaphysis.

Question 951

Topic: Bone Tumors

In adult patients presenting with new-onset dermatomyositis, the treating physician must have a high index of suspicion and screen for which of the following associated conditions?

. Osteosarcoma
. Underlying malignancy
. Type 1 diabetes mellitus
. Celiac disease
. Multiple sclerosis

Correct Answer & Explanation

. Underlying malignancy

Explanation

Adult-onset dermatomyositis has a strong association with underlying occult malignancies (e.g., ovarian, lung, gastrointestinal). Age-appropriate cancer screening is mandatory.

Question 952

Topic: Bone Tumors

A 19-year-old male presents with painful scoliosis and back pain that is poorly relieved by NSAIDs. Imaging reveals a 2.5 cm radiolucent lesion in the posterior elements of L3 with a mineralized center. What is the most likely diagnosis?

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

Correct Answer & Explanation

. Osteoblastoma

Explanation

The presentation of a painful, bone-forming lesion in the posterior spinal elements is typical for osteoblastoma or osteoid osteoma. A size greater than 2.0 cm generally distinguishes an osteoblastoma from an osteoid osteoma, and the pain is often less responsive to NSAIDs.

Question 953

Topic: Bone Tumors

A 68-year-old man presents with severe back pain and fatigue. Radiographs demonstrate diffuse osteopenia and multiple punched-out lytic lesions in the skull and vertebral bodies.

Which of the following is the most sensitive test to establish the diagnosis?

. Bone scintigraphy
. Serum and urine protein electrophoresis
. Erythrocyte sedimentation rate
. Alkaline phosphatase
. C-reactive protein

Correct Answer & Explanation

. Serum and urine protein electrophoresis

Explanation

Serum and urine protein electrophoresis (SPEP/UPEP) with immunofixation are the most sensitive initial tests for Multiple Myeloma, detecting monoclonal proteins. Bone scintigraphy is often cold (negative) because myeloma suppresses osteoblast activity.

Question 954

Topic: Bone Tumors

A 65-year-old male presents with deep bone pain in his lower back and ribs. Laboratory results show hypercalcemia and normocytic anemia. Radiographs reveal multiple "punched-out" lytic lesions in the skull and axial skeleton.

Which of the following is the most appropriate initial diagnostic test to confirm the underlying etiology?

. Alkaline phosphatase level
. Prostate-specific antigen (PSA)
. Serum protein electrophoresis (SPEP)
. Erythrocyte sedimentation rate (ESR)
. C-reactive protein (CRP)

Correct Answer & Explanation

. Serum protein electrophoresis (SPEP)

Explanation

The clinical presentation and "punched-out" lytic lesions are classic for Multiple Myeloma. SPEP and UPEP are the most appropriate initial tests, revealing a monoclonal spike (M-protein) in the majority of patients. It is the most common primary bone malignancy in adults.

Question 955

Topic: Bone Tumors

A 45-year-old male presents with polyneuropathy, organomegaly, endocrinopathy, an M-protein spike, and skin changes. Skeletal survey reveals predominantly osteosclerotic bone lesions. What is the most likely diagnosis?

. Multiple Myeloma
. Waldenstrom's Macroglobulinemia
. POEMS Syndrome
. Osteosarcoma
. Paget's Disease of Bone

Correct Answer & Explanation

. POEMS Syndrome

Explanation

POEMS syndrome is a rare paraneoplastic disorder secondary to a plasma cell dyscrasia. The acronym stands for Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, and Skin changes. Unlike classic multiple myeloma, the bone lesions in POEMS syndrome are predominantly osteosclerotic.

Question 956

Topic: Bone Tumors

A patient with multiple myeloma develops progressive acute kidney injury. Which of the following is the most common pathophysiologic cause of renal failure in these patients?

. Hyperuricemia leading to urate nephropathy
. Precipitation of free light chains in the distal renal tubules
. Direct infiltration of the renal parenchyma by plasma cells
. NSAID-induced interstitial nephritis
. Amyloid deposition in the renal glomeruli

Correct Answer & Explanation

. Precipitation of free light chains in the distal renal tubules

Explanation

Cast nephropathy (myeloma kidney) is the most common cause of renal failure in multiple myeloma. It is caused by the precipitation of monoclonal free light chains (Bence Jones proteins) with Tamm-Horsfall proteins in the distal convoluted tubules, forming obstructing casts. This leads to tubular damage and obstruction.

Question 957

Topic: Bone Tumors

When evaluating a patient with newly diagnosed Multiple Myeloma, which imaging modality is historically notorious for yielding falsely negative results when screening for bone lesions?

. Whole-body MRI
. Low-dose Whole-body CT
. Conventional skeletal survey
. Positron Emission Tomography (PET-CT)
. Technetium-99m bone scan

Correct Answer & Explanation

. Technetium-99m bone scan

Explanation

Technetium-99m bone scans rely on osteoblastic activity (bone formation) to show uptake. Multiple myeloma lesions are purely osteolytic, mediated by uncoupled osteoclastic activity with suppressed osteoblastic function. Therefore, bone scans are often falsely negative ("cold") in multiple myeloma.

Question 958

Topic: Bone Tumors

A 62-year-old man is suspected of having multiple myeloma after routine lab work shows elevated total protein with normal serum albumin. Which of the following imaging modalities is considered the most sensitive for detecting early osteolytic skeletal involvement and extramedullary disease in this patient?

. Technetium-99m bone scintigraphy
. Plain radiography skeletal survey
. Whole-body MRI
. Dual-energy X-ray absorptiometry (DEXA)
. Quantitative computed tomography (qCT)

Correct Answer & Explanation

. Whole-body MRI

Explanation

Whole-body MRI (and PET/CT) is significantly more sensitive than a plain radiographic skeletal survey for detecting early bone marrow involvement and extramedullary lesions in multiple myeloma. Technetium-99m bone scans are highly insensitive for myeloma because the lesions typically lack an osteoblastic response.

Question 959

Topic: Bone Tumors
A 14-year-old girl presents with a Shepherd's crook deformity of her proximal femur and irregularly bordered café-au-lait macules on her trunk. What is the underlying genetic and molecular mechanism of her disease?
. Inactivating mutation in EXT1 leading to disrupted heparan sulfate synthesis
. Activating mutation in GNAS leading to continuous production of cAMP
. Mutation in COL1A1 leading to defective type I collagen synthesis
. Inactivating mutation in RB1 leading to unchecked cellular proliferation
. Activating mutation in FGFR3 leading to inhibited chondrocyte proliferation

Correct Answer & Explanation

. Activating mutation in GNAS leading to continuous production of cAMP

Explanation

This patient has McCune-Albright syndrome, a severe form of polyostotic fibrous dysplasia. It is caused by a post-zygotic activating somatic mutation in the GNAS gene, which encodes the alpha subunit of the stimulatory G protein (Gs), resulting in continuous, unregulated production of intracellular cAMP.

Question 960

Topic: Bone Tumors

A 70-year-old man is newly diagnosed with multiple myeloma. Which of the following serum markers is considered the most significant independent prognostic factor for survival in this disease?

. Serum calcium level
. Beta-2 microglobulin
. Alkaline phosphatase
. C-reactive protein
. Monoclonal spike amplitude on SPEP

Correct Answer & Explanation

. Beta-2 microglobulin

Explanation

Serum Beta-2 microglobulin is the single most powerful and reliable independent prognostic factor for survival in multiple myeloma. It is used alongside serum albumin to stage the disease according to the International Staging System (ISS).

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