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10. Pathology and Oncology MCQs

Practice Set 344 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 6861

Topic: 10. Pathology and Oncology

A 65-year-old male presents with a slowly enlarging, painless soft tissue mass in the posterior subcutaneous neck. Excisional biopsy is performed. Histology demonstrates a mixture of mature adipocytes, uniform spindle cells, and thick, ropey collagen bundles in a myxoid background. Immunohistochemistry is positive for CD34. What is the most likely diagnosis?

. Atypical lipomatous tumor
. Pleomorphic liposarcoma
. Hibernoma
. Spindle cell lipoma
. Angiolipoma

Correct Answer & Explanation

. Spindle cell lipoma

Explanation

Spindle cell lipoma is a benign lipomatous tumor that classically occurs in the posterior neck/back of older males. Histologically, it is defined by a mixture of mature fat, uniform CD34-positive spindle cells, and distinct ropy collagen bundles.

Question 6862

Topic: Bone Tumors

During the surgical excision of a symptomatic solitary osteochondroma of the distal femur in a 20-year-old patient, which of the following oncologic principles is most critical to minimize the risk of local recurrence?

. Wide en bloc resection including 2 cm of normal cortical bone
. Complete removal of the cartilaginous cap and overlying perichondrium
. Intralesional curettage followed by phenol application
. Preoperative embolization to minimize bleeding from the cartilaginous cap
. Postoperative adjuvant external beam radiation therapy

Correct Answer & Explanation

. Complete removal of the cartilaginous cap and overlying perichondrium

Explanation

Symptomatic osteochondromas are treated with marginal excision. It is critical to completely excise the entire cartilaginous cap along with its overlying perichondrium; failure to do so leaves active chondrocytes behind, resulting in local recurrence.

Question 6863

Topic: 10. Pathology and Oncology
A 55-year-old woman is evaluated for a large mass deep in her thigh. MRI reveals a predominantly high T1-signal mass with thick, nodular, enhancing septations (>2 mm). Biopsy confirms an Atypical Lipomatous Tumor (ALT). Which of the following statements best describes the biological behavior and appropriate treatment for this specific tumor?
. It has high metastatic potential; requires wide excision and systemic chemotherapy.
. It does not metastasize but tends to recur locally; treated with marginal excision and close surveillance.
. It represents a reactive process; observed with serial MRI every 6 months.
. It is uniformly fatal without immediate forequarter or hindquarter amputation.
. It requires primary treatment with high-dose external beam radiation therapy alone.

Correct Answer & Explanation

. It does not metastasize but tends to recur locally; treated with marginal excision and close surveillance.

Explanation

Atypical Lipomatous Tumors (ALT) are locally aggressive but do not possess metastatic potential unless they undergo dedifferentiation. The standard of care is marginal surgical excision to minimize morbidity, recognizing that local recurrence may occur.

Question 6864

Topic: 10. Pathology and Oncology

A 30-year-old male with an established diagnosis of multiple hereditary exostoses presents with a newly enlarging, painful osteochondroma on his right iliac wing. He reached skeletal maturity 12 years ago. Imaging shows a cartilage cap measuring 3.5 cm in thickness. What is the most appropriate management?

. Reassurance and clinical observation with serial radiographs in 6 months
. Core needle biopsy followed by neoadjuvant chemotherapy
. Wide surgical resection of the lesion
. Intralesional curettage and bone grafting
. Administration of denosumab to halt lesion progression

Correct Answer & Explanation

. Wide surgical resection of the lesion

Explanation

A growing, painful osteochondroma with a cartilage cap >2 cm in a skeletally mature adult is highly suspicious for malignant transformation to secondary chondrosarcoma. The appropriate treatment for low-grade chondrosarcoma is wide surgical resection.

Question 6865

Topic: 10. Pathology and Oncology

A 14-year-old male presents with progressive, deep thigh pain that awakens him at night. Radiographs of the femur demonstrate a diaphyseal permeative lytic lesion with a prominent multi-layered, lamellated periosteal reaction. Based on the most likely diagnosis, what is the characteristic radiographic description of this periosteal reaction?

. Sunburst pattern
. Popcorn calcification
. Onion-skin appearance
. Codman's triangle
. Ground-glass matrix

Correct Answer & Explanation

. Onion-skin appearance

Explanation

Correct Answer: Onion-skin appearanceThe clinical presentation and radiographic findings of a diaphyseal permeative lesion in an adolescent are highly suspicious for Ewing's sarcoma. The classic periosteal reaction associated with Ewing's sarcoma is a multi-layered, lamellated appearance, commonly referred to as an 'onion-skin' reaction. A 'sunburst' pattern or 'Codman's triangle' is more classically associated with osteosarcoma, which typically arises in the metaphysis.

Question 6866

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a 2-month history of worsening thigh pain, particularly at night, and a low-grade fever. Radiographs of the femur reveal a permeative diaphyseal lesion with a prominent 'onion-skin' periosteal reaction. Which of the following genetic translocations is most characteristic of this patient's likely diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Correct Answer: AThe clinical and radiographic presentation (diaphyseal location, permeative destruction, 'onion-skin' periosteal reaction, systemic symptoms like fever) is classic for Ewing's sarcoma. Ewing's sarcoma is a small round blue cell tumor that is highly associated with the t(11;22) chromosomal translocation, which results in the EWS-FLI1 fusion protein. Osteosarcoma typically presents in the metaphysis with a 'sunburst' pattern or Codman's triangle.

Question 6867

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive thigh pain and swelling. Radiographs demonstrate a diaphyseal lesion with a lamellated, 'onion-skin' periosteal reaction. Based on the most likely diagnosis, what is the underlying pathophysiology of this specific radiographic finding?

. Rapid, discontinuous periosteal elevation by an aggressive tumor
. Slow-growing benign cortical expansion and remodeling
. Calcification of a cartilaginous matrix within the medullary canal
. Reactive bone formation secondary to a central radiolucent nidus
. Subperiosteal hemorrhage organizing after unrecognized trauma

Correct Answer & Explanation

. Rapid, discontinuous periosteal elevation by an aggressive tumor

Explanation

Correct Answer: Rapid, discontinuous periosteal elevation by an aggressive tumorThe clinical and radiographic presentation is classic for Ewing's sarcoma, which frequently affects the diaphysis of long bones in children and adolescents. The 'onion-skin' (lamellated) periosteal reaction occurs because the aggressive, rapidly growing tumor outpaces the periosteum's ability to lay down new bone continuously. The periosteum is repeatedly elevated, laying down multiple concentric layers of reactive bone.

Question 6868

Topic: 10. Pathology and Oncology

An 11-year-old boy presents with progressive thigh pain and swelling. Radiographs of the femur demonstrate a diaphyseal permeative lytic lesion with a prominent multi-layered, lamellated periosteal reaction. Based on the radiographic appearance, which of the following is the most likely diagnosis?

. Osteosarcoma
. Chondrosarcoma
. Ewing's sarcoma
. Osteoid osteoma
. Osteochondroma

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

Correct Answer: Ewing's sarcomaEwing's sarcoma is a highly malignant primary bone tumor that typically affects children and young adults. It most commonly arises in the diaphysis of long bones. The classic radiographic appearance includes a permeative, destructive lytic lesion with a lamellated or 'onion-skin' periosteal reaction. Osteosarcoma typically presents in the metaphysis with a 'sunburst' pattern or Codman's triangle.

Question 6869

Topic: 10. Pathology and Oncology

A 65-year-old male presents with generalized bone pain, fatigue, and recent onset of renal insufficiency. Radiographs of the skull and pelvis reveal multiple punched-out lytic lesions. Which of the following is the most common primary malignant bone tumor in this age demographic, consistent with this presentation?

. Osteosarcoma
. Chondrosarcoma
. Chordoma
. Multiple myeloma
. Fibrosarcoma

Correct Answer & Explanation

. Multiple myeloma

Explanation

Correct Answer: Multiple myelomaMultiple myeloma is a plasma cell dyscrasia and is the most common primary malignant bone tumor in adults. It typically presents in patients over 50 years old with bone pain, anemia, renal failure, hypercalcemia, and characteristic 'punched-out' lytic bone lesions on radiographs. While metastatic carcinoma is the most common malignancy found in bone overall, multiple myeloma is the most common primary bone malignancy.

Question 6870

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive, deep thigh pain that frequently awakens him at night. Radiographs of the femur demonstrate a destructive diaphyseal lesion with a prominent, multi-layered 'onion-skin' periosteal reaction. Based on the radiographic appearance and patient demographic, which of the following is the most likely diagnosis?

. Osteosarcoma
. Chondrosarcoma
. Ewing's sarcoma
. Osteoid osteoma
. Fibrous dysplasia

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

Correct Answer: CEwing's sarcoma is a highly malignant primary bone tumor that typically affects children and young adults in their second decade of life. It most commonly arises in the diaphysis of long bones (e.g., femur, tibia) or the pelvis. Radiographically, it is characterized by a permeative, destructive lytic lesion with a classic 'onion-skin' (lamellated) periosteal reaction, which represents sequential layers of reactive bone formation. Osteosarcoma, while the most common primary malignant bone tumor in children, typically presents in the metaphysis with a 'sunburst' pattern or Codman's triangle.

Question 6871

Topic: 10. Pathology and Oncology

A 65-year-old male presents with generalized bone pain, fatigue, and a recent onset of renal insufficiency. Radiographs of the skull and pelvis reveal multiple 'punched-out' lytic lesions without sclerotic margins. Based on epidemiological prevalence, what is the most likely primary malignant bone tumor in this patient demographic?

. Osteosarcoma
. Chondrosarcoma
. Ewing's sarcoma
. Multiple myeloma
. Chordoma

Correct Answer & Explanation

. Multiple myeloma

Explanation

Correct Answer: DMultiple myeloma is a plasma cell dyscrasia and is the most common primary malignant bone tumor in adults. It frequently presents with the 'CRAB' criteria: hyperCalcemia, Renal insufficiency, Anemia (fatigue), and Bone lesions. Radiographically, it is characterized by multiple 'punched-out' lytic bone lesions without surrounding reactive sclerosis, commonly involving the axial skeleton (skull, spine, pelvis). Osteosarcoma and Ewing's sarcoma are more common in children and adolescents, while chondrosarcoma is the second most common primary malignant bone tumor in adults.

Question 6872

Topic: 10. Pathology and Oncology

A 14-year-old boy is diagnosed with a conventional intramedullary osteosarcoma of the distal femur. A detailed family history reveals that his younger sister was treated for bilateral ocular tumors during infancy. Which genetic mutation is most likely responsible for both conditions in this family?

. TP53
. RB1
. EXT1
. GNAS
. NF1

Correct Answer & Explanation

. RB1

Explanation

The RB1 gene mutation causes familial retinoblastoma and significantly increases the risk of developing osteosarcoma later in life. While TP53 mutations also cause osteosarcoma (Li-Fraumeni syndrome), they are not primarily associated with retinoblastoma.

Question 6873

Topic: Bone Tumors

A 65-year-old male presents with a painful, destructive lytic lesion in his proximal femur. Laboratory analysis reveals anemia, hypercalcemia, and a prominent M-spike on serum protein electrophoresis. Which imaging modality is currently the most sensitive test for detecting systemic skeletal lesions in this patient?

. Technetium-99m bone scan
. Whole-body low-dose computed tomography (CT)
. Gallium-67 scan
. Indium-111 leukocyte scan
. Standard plain radiographic skeletal survey

Correct Answer & Explanation

. Whole-body low-dose computed tomography (CT)

Explanation

Whole-body low-dose CT (and whole-body MRI) is much more sensitive than standard plain radiographs for detecting lytic lesions in multiple myeloma. Technetium-99m bone scans rely on osteoblastic activity and are notoriously false-negative in myeloma.

Question 6874

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slow-growing, painful mass near his knee joint. MRI shows a deep, soft-tissue mass adjacent to the joint capsule. Biopsy reveals a biphasic pattern of spindle and epithelial cells. Which of the following chromosomal translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characterized by the t(X;18) translocation, resulting in the SYT-SSX fusion gene. This tumor typically arises near joints in young adults and can present with a biphasic or monophasic histologic pattern.

Question 6875

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with an enlarging, painful mass in his distal femur. Radiographs reveal a permeative lytic lesion with a 'sunburst' periosteal reaction. Biopsy confirms high-grade intramedullary osteosarcoma. Which genetic alteration is most classically associated with the pathogenesis of this tumor?

. t(11;22) chromosomal translocation
. t(X;18) chromosomal translocation
. Mutation of the EXT1 and EXT2 genes
. Inactivation of the Rb and p53 tumor suppressor genes
. Amplification of the MDM2 gene

Correct Answer & Explanation

. Inactivation of the Rb and p53 tumor suppressor genes

Explanation

High-grade intramedullary osteosarcoma is highly associated with mutations and inactivations in the Rb and p53 tumor suppressor genes. The t(11;22) translocation is characteristic of Ewing sarcoma, while t(X;18) is associated with synovial sarcoma.

Question 6876

Topic: 10. Pathology and Oncology

A 4-year-old child is evaluated for an asymmetric, painless swelling over the medial aspect of the right ankle. Radiographs show an irregular, ossified mass arising from the medial epiphysis of the distal tibia. A biopsy is performed. What is the expected histological appearance of this lesion?

. Disorganized woven bone with prominent osteoclasts
. Proliferation of lipid-laden histiocytes
. Histologically identical to an osteochondroma
. Avascular necrosis with creeping substitution
. Malignant chondrocytes with high mitotic figures

Correct Answer & Explanation

. Histologically identical to an osteochondroma

Explanation

Correct Answer: Histologically identical to an osteochondromaThe clinical and radiographic presentation is classic for Dysplasia Epiphysealis Hemimelica (Trevor disease). This is a rare developmental disorder characterized by an asymmetric cartilaginous overgrowth of an epiphysis, most commonly affecting the lower extremity (medial side of the distal femur, distal tibia, or talus). Histologically, the lesion is indistinguishable from an osteochondroma, featuring a cartilage cap overlying trabecular bone that is continuous with the underlying epiphysis.

Question 6877

Topic: Bone Tumors

A 5-year-old boy presents with a painless, asymmetric, hard swelling on the medial aspect of his right ankle. Radiographs demonstrate an irregular, stippled ossification mass arising directly from the medial epiphysis of the distal tibia. If this lesion were to be excised and examined histologically, the tissue would most closely resemble which of the following?

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

Correct Answer & Explanation

. Osteochondroma

Explanation

Correct Answer: A (Osteochondroma)The clinical and radiographic presentation is classic for Dysplasia Epiphysealis Hemimelica (also known as Trevor disease). This is a rare developmental disorder characterized by asymmetric cartilage overgrowth in the epiphyses, most commonly affecting the medial side of the lower extremity (ankle or knee). Histologically, the lesion is indistinguishable from an osteochondroma, consisting of a cartilage cap with underlying endochondral ossification. It is essentially an intra-articular osteochondroma arising from the epiphysis.

Question 6878

Topic: 10. Pathology and Oncology

A 7-year-old boy undergoes surgical excision of a symptomatic Dysplasia Epiphysealis Hemimelica (Trevor disease) lesion located on the medial aspect of the distal femoral epiphysis. Which of the following is the most likely long-term complication of this surgical intervention?

. Malignant transformation to chondrosarcoma
. Premature physeal closure and angular deformity
. Recurrent joint effusions
. Avascular necrosis of the femoral head
. Systemic dissemination of the lesion

Correct Answer & Explanation

. Premature physeal closure and angular deformity

Explanation

Correct Answer: B (Premature physeal closure and angular deformity)Trevor disease (Dysplasia Epiphysealis Hemimelica) involves an osteochondroma-like overgrowth arising directly from the epiphysis. Surgical excision is often indicated for pain, mechanical block to motion, or progressive deformity. However, because the lesion is intimately associated with the epiphysis and the adjacent physis, surgical excision carries a high risk of iatrogenic injury to the growth plate. This frequently leads to premature physeal closure, resulting in growth arrest and subsequent angular deformity.

Question 6879

Topic: 10. Pathology and Oncology

A 4-year-old boy presents with an asymmetric, painless swelling on the medial side of his right ankle. Radiographs show irregular, lobulated, cartilaginous overgrowth arising from the medial epiphysis of the distal tibia. A biopsy is performed. Which of the following best describes the expected histologic findings?

. Disorganized woven bone with prominent osteoclast giant cells
. Chondrocytes arranged in column-like clusters with abundant mucin
. A cartilage cap with organized endochondral ossification identical to an osteochondroma
. Malignant chondrocytes with binucleated cells and cortical destruction
. Accumulation of misfolded proteins within the rough endoplasmic reticulum

Correct Answer & Explanation

. A cartilage cap with organized endochondral ossification identical to an osteochondroma

Explanation

Dysplasia epiphysealis hemimelica (Trevor disease) represents an intra-articular osteochondroma-like lesion arising from an epiphysis. Histologically, it is indistinguishable from a classic osteochondroma.

Question 6880

Topic: 10. Pathology and Oncology

A 5-year-old boy presents with a painless, hard swelling on the medial aspect of his left ankle that is restricting his range of motion. Radiographs show an asymmetric, irregular ossified mass arising directly from the distal tibial epiphysis. Histology of a biopsy would most likely show which of the following?

. Proliferating histiocytes with eosinophils
. Hyaline cartilage cap mimicking an osteochondroma
. Chondroblasts with chicken-wire calcification
. Malignant spindle cells producing osteoid
. Giant cells interspersed with mononuclear stroma

Correct Answer & Explanation

. Hyaline cartilage cap mimicking an osteochondroma

Explanation

Dysplasia epiphysealis hemimelica (Trevor's disease) is characterized by asymmetric epiphyseal cartilage overgrowth. Histologically, the lesions are indistinguishable from osteochondromas, featuring a benign hyaline cartilage cap.

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