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10. Pathology and Oncology MCQs

Practice Set 278 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 5541

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive distal thigh pain. Radiographs demonstrate a destructive metaphyseal lesion with a 'sunburst' periosteal reaction. Biopsy reveals malignant spindle cells producing unmineralized osteoid. What is the most appropriate initial step in treatment?

. Primary above-knee amputation
. Neoadjuvant chemotherapy
. Wide local excision
. Adjuvant external beam radiation
. Intralesional curettage and bone grafting

Correct Answer & Explanation

. Neoadjuvant chemotherapy

Explanation

The presentation is classic for high-grade conventional osteosarcoma. The standard of care consists of neoadjuvant chemotherapy, followed by wide surgical resection (limb salvage or amputation), and then adjuvant chemotherapy.

Question 5542

Topic: 10. Pathology and Oncology

A 65-year-old male presents with back pain. Radiographs reveal multiple 'punched-out' lytic lesions in the skull and vertebrae. Serum protein electrophoresis shows a monoclonal spike. What is the most common orthopedic indication for surgical intervention in this disease process?

. Impending or actual pathologic fracture
. Spinal cord compression from epidural tumor extension
. Hypercalcemic crisis
. Amyloid arthropathy
. Chronic osteomyelitis

Correct Answer & Explanation

. Impending or actual pathologic fracture

Explanation

Multiple myeloma is the most common primary bone malignancy in adults. Orthopedic surgical intervention is most frequently indicated for stabilization of actual or impending pathologic fractures, particularly in the long bones and spine.

Question 5543

Topic: 10. Pathology and Oncology

A 42-year-old female presents with severe pain in her right ring finger exacerbated by exposure to cold. On exam, she has exquisite pinpoint tenderness over the nail bed. Application of a tourniquet to the base of the digit completely abolishes her pain. What is the most likely diagnosis?

. Giant cell tumor of the tendon sheath
. Enchondroma
. Glomus tumor
. Epidermal inclusion cyst
. Neuroma

Correct Answer & Explanation

. Glomus tumor

Explanation

The clinical scenario describes the classic triad of a glomus tumor: severe paroxysmal pain, point tenderness (Love's pin test), and cold intolerance. The abolition of pain with tourniquet ischemia is known as Hildreth's sign, which is highly specific for a glomus tumor. These are benign hamartomas of the neuromyoarterial glomus body.

Question 5544

Topic: 10. Pathology and Oncology

A 35-year-old woman complains of severe, paroxysmal pain in her left index finger, which is exacerbated by cold weather. Examination reveals pinpoint tenderness over the nail bed, and placing a tourniquet at the finger base relieves the pain. Radiographs demonstrate mild scalloping of the dorsal aspect of the distal phalanx. What is the most likely diagnosis?

. Enchondroma
. Giant cell tumor of tendon sheath
. Glomus tumor
. Epidermal inclusion cyst
. Mucoid cyst

Correct Answer & Explanation

. Glomus tumor

Explanation

The patient exhibits the classic triad for a glomus tumor: cold sensitivity, paroxysmal pain, and pinpoint tenderness (Love's sign). The relief of pain with ischemia (tourniquet) is known as Hildreth's sign. Glomus tumors are benign hamartomas of the neuromyoarterial glomus body and frequently cause scalloping on the dorsal distal phalanx.

Question 5545

Topic: 10. Pathology and Oncology

A 35-year-old woman presents with severe, sharp pain in her left ring finger tip, which worsens in cold weather. Exam shows a subtle bluish discoloration beneath the nail plate. The pain is completely abolished when a pneumatic tourniquet is inflated at the base of the finger. What is the most likely diagnosis?

. Enchondroma
. Glomus tumor
. Mucous cyst
. Subungual melanoma
. Epidermal inclusion cyst

Correct Answer & Explanation

. Glomus tumor

Explanation

A glomus tumor is a benign hamartoma of the glomus body (a neuromyoarterial glomus involved in thermoregulation). The classic clinical triad includes cold hypersensitivity, paroxysmal severe pain, and pinpoint point tenderness (Love's test). The abolition of pain upon inflation of a proximal tourniquet is known as Hildreth's sign, which is highly specific for a glomus tumor.

Question 5546

Topic: 10. Pathology and Oncology

A 60-year-old woman with long-standing rheumatoid arthritis presents with an inability to extend her small, ring, and long fingers at the metacarpophalangeal (MCP) joints. She first noticed the drop in her small finger two months ago, which progressively involved the ring and long fingers. What is the most likely diagnosis?

. Posterior interosseous nerve syndrome
. Mannerfelt syndrome
. Vaughan-Jackson syndrome
. Sagittal band rupture
. Malignant infiltration of the extensor retinaculum

Correct Answer & Explanation

. Vaughan-Jackson syndrome

Explanation

Vaughan-Jackson syndrome refers to the sequential attritional rupture of the extensor tendons, typically starting ulnarly (extensor digiti minimi and extensor digitorum communis to the small finger) and progressing radially. This is caused by friction over a dorsally prominent, subluxated distal ulna (caput ulnae syndrome) commonly seen in rheumatoid arthritis. Mannerfelt syndrome refers to the attritional rupture of the FPL tendon over a prominent volar scaphoid osteophyte.

Question 5547

Topic: 10. Pathology and Oncology

A 65-year-old man presents with a slow-growing, firm, painless mass on the volar aspect of his right wrist. MRI reveals a well-circumscribed soft tissue mass along the median nerve. An incisional biopsy demonstrates biphasic architecture with hypercellular Antoni A areas and hypocellular Antoni B areas. Which of the following is true regarding the surgical management of this lesion?

. It represents a neurofibroma and cannot be resected without sacrificing nerve fascicles.
. Radical en bloc resection is required due to the high rate of malignant transformation.
. The mass can usually be enucleated because it displaces, rather than infiltrates, the continuous nerve fascicles.
. Post-operative radiation therapy is universally recommended following marginal excision.
. Amputation is the treatment of choice if it occurs in a digital nerve.

Correct Answer & Explanation

. The mass can usually be enucleated because it displaces, rather than infiltrates, the continuous nerve fascicles.

Explanation

The pathology describes a schwannoma (neurilemmoma), which is the most common benign peripheral nerve sheath tumor. Schwannomas grow eccentrically from the nerve sheath, displacing the nerve fascicles to the periphery. Because they do not infiltrate the fascicles (unlike neurofibromas), schwannomas can typically be carefully dissected and enucleated under magnification, sparing the native nerve function.

Question 5548

Topic: 10. Pathology and Oncology

A 16-year-old male is diagnosed with high-grade conventional osteosarcoma. A mutation in the TP53 gene is identified in the tumor tissue. A germline mutation in this specific gene is classically associated with which of the following inherited cancer predisposition syndromes?

. Rothmund-Thomson syndrome
. Li-Fraumeni syndrome
. Hereditary Multiple Exostoses
. McCune-Albright syndrome
. Neurofibromatosis type 1

Correct Answer & Explanation

. Li-Fraumeni syndrome

Explanation

Li-Fraumeni syndrome is a rare, autosomal dominant disorder caused by germline mutations in the TP53 tumor suppressor gene. Individuals with this syndrome have a profoundly increased lifetime risk of developing multiple primary cancers, predominantly osteosarcomas, soft tissue sarcomas, early-onset breast cancers, and brain tumors.

Question 5549

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a painful mass in the distal femur. Biopsy reveals malignant spindle cells producing an immature osteoid matrix. Which of the following genetic pathways is most commonly mutated in this primary bone sarcoma?

. t(11;22) chromosomal translocation
. t(X;18) chromosomal translocation
. Retinoblastoma (Rb) and TP53 tumor suppressor genes
. GNAS1 gene mutation
. EXT1 and EXT2 gene mutations

Correct Answer & Explanation

. Retinoblastoma (Rb) and TP53 tumor suppressor genes

Explanation

The biopsy describes osteosarcoma. Alterations in the Rb and TP53 tumor suppressor pathways are the most common genetic mutations associated with conventional osteosarcoma. The t(11;22) translocation is characteristic of Ewing sarcoma; t(X;18) is seen in synovial sarcoma; GNAS1 in fibrous dysplasia; and EXT1/EXT2 in multiple hereditary exostoses.

Question 5550

Topic: 10. Pathology and Oncology
A 55-year-old female with metastatic breast cancer presents with hip pain. Radiographs reveal a 4 cm lytic lesion in the peritrochanteric region of the right femur, occupying approximately 50% of the cortical diameter. She describes her pain as moderate with weight-bearing. According to Mirels' criteria, what is her score and recommended management?
. Score 7; Observation and localized radiation therapy
. Score 8; Protected weight bearing and bisphosphonates
. Score 9; Observation with serial radiographs
. Score 10; Prophylactic internal fixation
. Score 11; Neoadjuvant chemotherapy followed by wide resection

Correct Answer & Explanation

. Score 10; Prophylactic internal fixation

Explanation

Mirels' criteria evaluate the risk of pathologic fracture based on four factors (1 to 3 points each): Site (Upper limb=1, Lower limb=2, Peritrochanteric=3); Pain (Mild=1, Moderate=2, Severe=3); Lesion type (Blastic=1, Mixed=2, Lytic=3); Size (<1/3 cortex=1, 1/3-2/3 cortex=2, >2/3 cortex=3). This patient's score: Peritrochanteric (3) + Moderate pain (2) + Lytic (3) + Size 50% (2) = 10. A score ≥ 9 indicates a high risk of impending fracture, and prophylactic internal fixation is highly recommended.

Question 5551

Topic: 10. Pathology and Oncology

A 15-year-old boy is diagnosed with conventional osteosarcoma of the distal femur. A detailed family history reveals that his mother died of breast cancer at age 35, and his sister was treated for childhood leukemia. A germline mutation in which of the following genes is most likely responsible for this familial cancer syndrome?

. EXT1
. RB1
. TP53
. GNAS
. APC

Correct Answer & Explanation

. TP53

Explanation

The clinical picture describes Li-Fraumeni syndrome, an autosomal dominant disorder characterized by a high incidence of childhood and early adult tumors, including osteosarcoma, breast cancer, leukemia, and soft tissue sarcomas. It is caused by a germline mutation in the TP53 tumor suppressor gene. RB1 mutations are associated with hereditary retinoblastoma, which also increases osteosarcoma risk, but does not fit the multi-tumor profile seen here.

Question 5552

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a destructive, permeative diaphyseal lesion of the femur with an associated soft tissue mass. Biopsy reveals sheets of uniform, small round blue cells. Cytogenetic analysis of this tumor is most likely to reveal which of the following translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma classically presents as a diaphyseal lesion with small round blue cells. The hallmark genetic mutation is the t(11;22) translocation, which produces the EWS-FLI1 fusion protein.

Question 5553

Topic: 10. Pathology and Oncology

A 30-year-old patient presents with a lytic lesion in the distal femur epiphysis. The lesion is treated with curettage and cementing. Which of the following best describes the classical histological appearance of a Giant Cell Tumor of bone?

. Atypical cells producing lace-like osteoid matrix
. Sheets of small round blue cells with Homer Wright rosettes
. Multinucleated giant cells distributed evenly among neoplastic mononuclear stromal cells
. Chondrocytes with prominent nucleoli within a lobulated myxoid background
. Fibroblastic spindle cells arranged in a prominent storiform pattern

Correct Answer & Explanation

. Multinucleated giant cells distributed evenly among neoplastic mononuclear stromal cells

Explanation

Giant Cell Tumor of bone is characterized histologically by numerous osteoclast-like multinucleated giant cells scattered evenly throughout a background of plump, neoplastic mononuclear stromal cells. The mononuclear cells express RANKL, driving the formation of the giant cells.

Question 5554

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with an aggressive permeative diaphyseal lesion in his femur with a laminated periosteal reaction. Biopsy reveals sheets of uniform small round blue cells. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is classically characterized by the t(11;22) chromosomal translocation, resulting in the EWS-FLI1 fusion protein. It typically presents as a permeative diaphyseal bone lesion in children and young adults.

Question 5555

Topic: 10. Pathology and Oncology

A 16-year-old male receives neoadjuvant chemotherapy for a conventional high-grade osteosarcoma of the distal femur. Which of the following factors obtained from the definitive surgical resection specimen is the most important prognostic indicator for overall survival?

. The initial volume of the tumor prior to biopsy
. The histologic percentage of tumor necrosis
. The specific histologic subtype (e.g., osteoblastic vs. fibroblastic)
. The exact distance of the negative surgical margin
. The presence of an associated pathologic fracture

Correct Answer & Explanation

. The histologic percentage of tumor necrosis

Explanation

In conventional high-grade osteosarcoma, the histologic response to neoadjuvant chemotherapy is the single most important prognostic indicator. Greater than 90% tumor necrosis in the resected specimen correlates with significantly improved long-term survival.

Question 5556

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with knee pain. Radiographs show a destructive, mixed lytic and sclerotic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Histology reveals malignant spindle cells producing osteoid. What is the most critical prognostic factor for his overall survival?

. Size of the primary tumor
. Anatomic location of the tumor
. Presence of skip metastases
. Histologic response to neoadjuvant chemotherapy
. Serum alkaline phosphatase levels at diagnosis

Correct Answer & Explanation

. Histologic response to neoadjuvant chemotherapy

Explanation

In osteosarcoma, the degree of tumor necrosis following neoadjuvant chemotherapy (>90% necrosis is considered a good response) is the most significant prognostic factor for overall disease-free survival.

Question 5557

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain and a destructive, lytic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. A biopsy shows malignant spindle cells producing osteoid. Which of the following genetic abnormalities is most commonly associated with this tumor's classic variant?

. t(11;22) translocation
. t(x;18) translocation
. Mutations in the RB1 and TP53 genes
. MDM2 gene amplification
. GNAS mutation

Correct Answer & Explanation

. Mutations in the RB1 and TP53 genes

Explanation

The clinical picture and biopsy describe conventional osteosarcoma. Classic genetic associations for osteosarcoma include mutations in the retinoblastoma (RB1) and TP53 tumor suppressor genes. The t(11;22) translocation is seen in Ewing sarcoma. MDM2 amplification is a hallmark of parosteal osteosarcoma. GNAS mutations are seen in fibrous dysplasia.

Question 5558

Topic: 10. Pathology and Oncology

When performing a biopsy of a suspected malignant primary bone tumor in the distal femur, which of the following oncologic principles is most critical to follow to prevent compromising definitive limb salvage?

. Make a transverse incision to minimize skin tension
. Raise wide fascial flaps to ensure adequate exposure
. Ensure the biopsy tract is located in the planned definitive resection bed
. Obtain an excisional biopsy regardless of tumor size
. Use a tourniquet and exsanguinate the limb prior to incision

Correct Answer & Explanation

. Ensure the biopsy tract is located in the planned definitive resection bed

Explanation

The biopsy tract is considered contaminated with tumor cells and must be excised en bloc during definitive surgery. Incisions must be longitudinal, and exsanguination is contraindicated to avoid systemic tumor spread.

Question 5559

Topic: Bone Tumors

A 14-year-old boy presents with progressive knee pain. Radiographs reveal an eccentric, expansile, lytic lesion in the distal femoral metaphysis. MRI demonstrates multiple fluid-fluid levels within the lesion. What is the most likely diagnosis?

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

Correct Answer & Explanation

. Aneurysmal bone cyst

Explanation

An aneurysmal bone cyst (ABC) typically presents as a benign, eccentric, blood-filled lytic lesion in the metaphysis of growing children. Fluid-fluid levels on MRI, representing layering of blood products, are a classic hallmark.

Question 5560

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive knee pain. Radiographs reveal a metaphyseal, permeative, lytic lesion in the distal femur with a 'sunburst' periosteal reaction. Biopsy shows pleomorphic cells producing fine, lace-like matrix. What is the most likely diagnosis?

. Ewing sarcoma
. Chondrosarcoma
. Osteosarcoma
. Aneurysmal bone cyst
. Nonossifying fibroma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The presence of a sunburst periosteal reaction and pleomorphic malignant cells producing osteoid (lace-like matrix) is pathognomonic for osteosarcoma. Ewing sarcoma typically presents with an 'onion-skin' reaction and small round blue cells.

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