Menu

10. Pathology and Oncology MCQs

Practice Set 281 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 5601

Topic: 10. Pathology and Oncology

A 10-year-old boy presents with severe, unrelenting diaphyseal thigh pain. Radiographs reveal a permeative lytic lesion with an "onion-skin" periosteal reaction in the femur diaphysis. Which of the following chromosomal translocations is pathognomonic for this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. Over 90% of Ewing sarcomas are driven by the t(11;22)(q24;q12) translocation, which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11.

Question 5602

Topic: 10. Pathology and Oncology

A 55-year-old woman with chronic kidney disease presents with a painful, radiolucent lesion in her right humerus. Laboratory tests reveal markedly elevated parathyroid hormone (PTH) and alkaline phosphatase. Biopsy of the lesion shows fibrovascular tissue, hemosiderin deposition, and numerous multinucleated giant cells. What is the most likely diagnosis?

. Aneurysmal bone cyst
. Giant cell tumor of bone
. Brown tumor
. Chondroblastoma
. Multiple myeloma

Correct Answer & Explanation

. Brown tumor

Explanation

A Brown tumor (osteitis fibrosa cystica) is a localized accumulation of fibrous tissue, giant cells, and hemosiderin (giving a brown color) that occurs in the setting of severe primary or secondary hyperparathyroidism. It resolves with treatment of the underlying endocrine condition.

Question 5603

Topic: 10. Pathology and Oncology

A 60-year-old man presents with a slowly enlarging, painful pelvic mass. Imaging shows a lytic lesion with "ring and arc" calcifications. Biopsy demonstrates atypical chondrocytes in a hyaline cartilage matrix. What is the most appropriate definitive management?

. Neoadjuvant chemotherapy followed by wide excision
. Primary radiation therapy
. Intralesional curettage and bone grafting
. Wide surgical excision alone
. Observation and serial imaging

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

The diagnosis is conventional chondrosarcoma, which is characteristically highly resistant to both chemotherapy and radiation therapy. Wide surgical excision is the mainstay of treatment for localized disease to ensure negative margins.

Question 5604

Topic: 10. Pathology and Oncology

A 10-year-old girl presents with a diaphyseal mass in her right fibula. Biopsy shows a uniform population of small, round, blue cells. Which specific chromosomal translocation is most diagnostic for this condition?

. 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 associated with the t(11;22) chromosomal translocation. This specific genetic alteration results in the formation of the EWS-FLI1 fusion protein.

Question 5605

Topic: 10. Pathology and Oncology

A 55-year-old man is diagnosed with a primary conventional grade II chondrosarcoma of the proximal humerus based on a biopsy. Radiographs show intralesional stippled calcifications. What is the most appropriate definitive management?

. Neoadjuvant chemotherapy followed by wide resection
. Radiation therapy alone
. Intralesional curettage with phenol adjuvant
. Wide surgical resection alone
. Limb amputation

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas are historically highly resistant to both chemotherapy and radiation therapy. The standard of care for intermediate and high-grade chondrosarcoma is wide surgical resection alone.

Question 5606

Topic: Bone Tumors

A 20-year-old man complains of severe, aching thigh pain that is notoriously worse at night and dramatically improves with NSAIDs. Radiographs reveal focal cortical thickening in the proximal femur with a central radiolucent nidus. What is the principal molecular mediator responsible for the intense pain in this lesion?

. Interleukin-1
. Tumor necrosis factor-alpha
. Prostaglandin E2
. Bradykinin
. Substance P

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteomas produce extremely high local levels of Prostaglandin E2 (PGE2) due to marked upregulation of COX-2 expression within the nidus. This accounts for the intense nocturnal pain and the dramatic relief provided by NSAIDs.

Question 5607

Topic: 10. Pathology and Oncology
A 15-year-old boy presents with knee pain. Radiographs show a sunburst periosteal reaction and Codman's triangle in the distal femur. Biopsy confirms high-grade osteosarcoma. What is the most significant prognostic factor for overall survival in this patient?
. Histologic subtype
. Tumor volume at presentation
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Presence of skip metastases
. Serum alkaline phosphatase level

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for overall survival in high-grade osteosarcoma. Greater than 90% necrosis (Huvos grade III/IV) indicates a good response and confers a significantly better prognosis.

Question 5608

Topic: 10. Pathology and Oncology

A 14-year-old boy is diagnosed with osteosarcoma of the distal femur. Genetic analysis reveals a somatic mutation in the TP53 gene. Which of the following inherited syndromes is characterized by a germline mutation of this exact gene?

. Li-Fraumeni syndrome
. Familial adenomatous polyposis
. Multiple hereditary exostoses
. McCune-Albright syndrome
. Neurofibromatosis type 1

Correct Answer & Explanation

. Li-Fraumeni syndrome

Explanation

Li-Fraumeni syndrome is an autosomal dominant disorder caused by a germline mutation in the TP53 tumor suppressor gene. It significantly increases the risk of developing osteosarcoma, breast cancer, and soft tissue sarcomas.

Question 5609

Topic: 10. Pathology and Oncology

In the Enneking surgical staging system for malignant musculoskeletal tumors, what does a Stage IIB lesion specifically signify?

. Low-grade tumor, intracompartmental
. Low-grade tumor, extracompartmental
. High-grade tumor, intracompartmental
. High-grade tumor, extracompartmental
. Any grade tumor with regional lymph node metastasis

Correct Answer & Explanation

. High-grade tumor, extracompartmental

Explanation

The Enneking system stages malignant tumors by histologic grade (I = low, II = high) and anatomical site (A = intracompartmental, B = extracompartmental). Therefore, Stage IIB strictly represents a high-grade, extracompartmental lesion without distant metastasis.

Question 5610

Topic: 10. Pathology and Oncology

A 14-year-old boy is diagnosed with high-grade intramedullary osteosarcoma of the distal femur and undergoes neoadjuvant chemotherapy followed by surgical resection. Which of the following is the most important prognostic factor for his long-term survival?

. Initial size of the primary tumor
. Preoperative serum alkaline phosphatase levels
. The specific anatomic location of the tumor
. The percentage of tumor necrosis observed in the resected specimen
. The type of surgical reconstruction performed

Correct Answer & Explanation

. The percentage of tumor necrosis observed in the resected specimen

Explanation

The histologic response to neoadjuvant chemotherapy, defined by the percentage of tumor necrosis, is the single most important prognostic factor in osteosarcoma. Greater than 90% necrosis indicates a good response and correlates with significantly higher survival rates.

Question 5611

Topic: 10. Pathology and Oncology

A patient develops tachycardia, muscle rigidity, and rapidly rising body temperature shortly after receiving succinylcholine during induction for fracture fixation. This condition is most commonly associated with a genetic mutation affecting which of the following?

. Dihydropyridine receptor
. Ryanodine receptor (RYR1)
. Nicotinic acetylcholine receptor
. Voltage-gated sodium channel
. Sarcoplasmic reticulum calcium-ATPase pump

Correct Answer & Explanation

. Ryanodine receptor (RYR1)

Explanation

Malignant hyperthermia is a hypermetabolic crisis most commonly caused by a mutation in the RYR1 gene. This mutation leads to an uncontrolled release of calcium from the sarcoplasmic reticulum when triggered by volatile anesthetics or depolarizing muscle relaxants.

Question 5612

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive knee pain. Radiographs reveal a destructive metaphyseal lesion of the distal femur with a 'sunburst' periosteal reaction. A biopsy confirms osteosarcoma. Histologically, which feature is essential for the diagnosis of this specific malignancy?

. Malignant cartilage with secondary endochondral ossification
. Production of osteoid by malignant mesenchymal cells
. Small round blue cells with Homer Wright rosettes
. Multinucleated giant cells in a background of benign spindle cells
. Sheets of clear cells with abundant intracellular glycogen

Correct Answer & Explanation

. Production of osteoid by malignant mesenchymal cells

Explanation

The defining histological characteristic of classic osteosarcoma is the production of malignant osteoid or immature bone by malignant mesenchymal cells. While other elements like cartilage or fibrous tissue may be present, the presence of malignant osteoid is required for diagnosis.

Question 5613

Topic: 10. Pathology and Oncology

A 30-year-old male presents with a lytic, eccentrically located epiphyseal lesion in the distal femur. Biopsy reveals numerous multinucleated giant cells in a background of mononuclear stromal cells. Which cell type represents the true neoplastic component of this tumor?

. Multinucleated giant cells
. Spindle-shaped mononuclear stromal cells
. Reactive histiocytes
. Osteoclasts
. Malignant chondroblasts

Correct Answer & Explanation

. Spindle-shaped mononuclear stromal cells

Explanation

In a Giant Cell Tumor of bone, the true neoplastic cells are the mononuclear spindle-shaped stromal cells, which are of osteoblast lineage. The multinucleated giant cells are reactive, non-neoplastic osteoclast-like cells recruited by RANKL secreted by the stromal cells.

Question 5614

Topic: 10. Pathology and Oncology

A 14-year-old boy has a permeative diaphyseal lesion in his femur with an associated soft tissue mass. Biopsy reveals small blue round cells. Which chromosomal translocation is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized by the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein. Other examples include t(9;22) in extraskeletal myxoid chondrosarcoma and t(X;18) in synovial sarcoma.

Question 5615

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a diaphysial lesion of the femur characterized by an 'onion skin' periosteal reaction. A biopsy confirms Ewing sarcoma. Which of the following chromosomal translocations is most commonly associated with this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is classically driven by the t(11;22)(q24;q12) translocation in ~85% of cases, resulting in the EWS-FLI1 fusion gene. t(9;22) is seen in myxoid chondrosarcoma; t(12;16) in myxoid liposarcoma; t(X;18) in synovial sarcoma; and t(2;13) in alveolar rhabdomyosarcoma.

Question 5616

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with thigh pain and fever. Radiographs show a permeative diaphyseal lesion in the femur with a prominent 'onion-skin' periosteal reaction. Biopsy reveals sheets of small round blue cells. Cytogenetic analysis is most likely to show which of the following translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized histologically by small round blue cells that are CD99 positive. It classically exhibits the t(11;22) translocation, which fuses the EWS gene to the FLI1 gene. The other translocations correspond to chondrosarcoma/CML (9;22), myxoid liposarcoma (12;16), synovial sarcoma (X;18), and alveolar rhabdomyosarcoma (2;13).

Question 5617

Topic: 10. Pathology and Oncology

A 62-year-old woman with a history of breast cancer presents with a newly identified lytic lesion in her right proximal femur (peritrochanteric region). The lesion involves 2/3 of the cortical diameter and is highly painful with weight-bearing. According to Mirels' criteria, what is the most appropriate management for this lesion?

. Observation and bisphosphonates alone
. Radiation therapy alone
. Chemotherapy followed by repeat radiographs in 4 weeks
. Prophylactic internal fixation
. Wide en bloc resection and endoprosthetic reconstruction

Correct Answer & Explanation

. Prophylactic internal fixation

Explanation

Mirels' criteria predict the risk of pathologic fracture. The four categories are Site (Upper extremity=1, Lower extremity=2, Peritrochanteric=3), Pain (Mild=1, Moderate=2, Functional=3), Lesion type (Blastic=1, Mixed=2, Lytic=3), and Size (<1/3=1, 1/3-2/3=2, >2/3=3). This patient's score is Peritrochanteric (3) + Functional pain (3) + Lytic (3) + Size >=2/3 (2 or 3) = 11 or 12. A score of 9 or greater carries a high risk of fracture, making prophylactic internal fixation the standard of care.

Question 5618

Topic: 10. Pathology and Oncology

A 55-year-old woman presents with bone pain and a radiolucent lesion in her left proximal tibia. Laboratory tests reveal elevated serum calcium, decreased serum phosphate, and elevated alkaline phosphatase. A biopsy of the lesion reveals clusters of multinucleated giant cells within a highly vascularized, fibrous stroma containing abundant hemosiderin deposits. Which of the following is the most likely diagnosis?

. Giant cell tumor of bone
. Aneurysmal bone cyst
. Osteitis fibrosa cystica (Brown tumor)
. Chondromyxoid fibroma
. Multiple myeloma

Correct Answer & Explanation

. Osteitis fibrosa cystica (Brown tumor)

Explanation

The patient's laboratory values (hypercalcemia and hypophosphatemia) are pathognomonic for primary hyperparathyroidism. The histologic findings of multinucleated giant cells in a fibrovascular stroma with hemosiderin (which imparts a brown color macroscopically) represent a Brown tumor, which is the hallmark focal lesion of osteitis fibrosa cystica resulting from severe hyperparathyroidism.

Question 5619

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a slow-growing, painful mass near her knee joint. Imaging reveals a calcified soft-tissue mass adjacent to but not involving the articular cavity. A biopsy reveals a biphasic spindle cell and epithelial cell morphology. Which cytogenetic abnormality is diagnostic for this tumor?

. t(9;22)(q22;q12)
. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)
. t(11;22)(q24;q12)

Correct Answer & Explanation

. t(X;18)(p11;q11)

Explanation

The clinical presentation (young adult, painful juxta-articular mass with calcifications) and biphasic histology (epithelial and spindle cells) are classic for synovial sarcoma. This tumor is definitively characterized by the t(X;18)(p11;q11) chromosomal translocation, which results in the SYT-SSX fusion gene.

Question 5620

Topic: 10. Pathology and Oncology

A 14-year-old male presents with distal femur pain. Imaging shows a sunburst periosteal reaction. Biopsy reveals malignant spindle cells producing osteoid. What is the most significant prognostic factor for long-term survival in this patient?

. Tumor size at diagnosis
. Histologic response to neoadjuvant chemotherapy
. Alkaline phosphatase level
. Surgical margins
. Presence of skip metastases

Correct Answer & Explanation

. Histologic response to neoadjuvant chemotherapy

Explanation

The most significant prognostic factor in conventional osteosarcoma is the histologic response to neoadjuvant chemotherapy, defined by the percentage of tumor necrosis. Greater than 90% necrosis portends a significantly better overall prognosis.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page