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10. Pathology and Oncology MCQs

Practice Set 36 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 701

Topic: 10. Pathology and Oncology
A 55-year-old woman is diagnosed with a Grade II conventional chondrosarcoma of the ilium. Staging studies reveal no evidence of metastatic disease. What is the standard of care for this patient?
. Neoadjuvant chemotherapy followed by wide resection
. Intralesional curettage with phenol adjuvant
. Primary external beam radiation
. Wide surgical resection alone
. Preoperative embolization and marginal excision

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas (especially Grade II and III) are highly resistant to both chemotherapy and radiation therapy. Wide surgical resection with negative margins is the definitive standard of care to maximize survival and minimize local recurrence.

Question 702

Topic: Bone Tumors

A 16-year-old boy is receiving standard neoadjuvant chemotherapy (MAP regimen) for an osteosarcoma of the distal femur. During the course of his treatment, he develops signs of congestive heart failure. Which of the following agents is most likely responsible for this complication?

. Methotrexate
. Cisplatin
. Doxorubicin
. Ifosfamide
. Etoposide

Correct Answer & Explanation

. Doxorubicin

Explanation

Doxorubicin (Adriamycin) is an anthracycline known for its dose-dependent, cumulative cardiotoxicity, which can lead to dilated cardiomyopathy and congestive heart failure. Cisplatin is primarily nephrotoxic and ototoxic, while methotrexate can cause hepatotoxicity and mucositis.

Question 703

Topic: 10. Pathology and Oncology

A 14-year-old boy has an incidental finding of a non-ossifying fibroma (NOF) in the proximal tibia. He is completely asymptomatic. During a discussion with the parents regarding the natural history of this lesion, which of the following statements is most accurate?

. It has a 5% risk of malignant transformation to fibrosarcoma.
. It typically enlarges aggressively after skeletal maturity.
. It generally moves progressively toward the diaphysis and ossifies over time.
. It requires prophylactic radiation to prevent pathological fracture.
. It originates from ectopic cartilaginous rests in the metaphysis.

Correct Answer & Explanation

. It generally moves progressively toward the diaphysis and ossifies over time.

Explanation

Non-ossifying fibromas (NOFs) originate at the physis and migrate toward the diaphysis as the bone grows. They are self-limiting, benign lesions that typically "heal" by progressive ossification (sclerosis) and eventually disappear by skeletal maturity.

Question 704

Topic: 10. Pathology and Oncology

Recent advances in the molecular pathology of cartilaginous tumors have identified specific genetic mutations. Which of the following mutations is highly prevalent in solitary enchondromas and conventional central chondrosarcomas?

. TP53
. RB1
. IDH1 and IDH2
. GNAS
. H3F3A

Correct Answer & Explanation

. IDH1 and IDH2

Explanation

Mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2) are found in a majority of central enchondromas and conventional central chondrosarcomas. They are also universally present in the multiple enchondromatosis syndromes, Ollier disease and Maffucci syndrome.

Question 705

Topic: 10. Pathology and Oncology

A 72-year-old man with a long-standing history of Paget's disease of bone presents with severe, progressive pain and new swelling in his right proximal femur. Radiographs reveal a new destructive, lytic lesion with cortical breakthrough and soft tissue extension within an area of thickened, trabeculated bone. Biopsy confirms malignant transformation. What is the most likely diagnosis and associated prognosis?

. Chondrosarcoma; excellent prognosis with wide resection
. Osteosarcoma; excellent prognosis with modern chemotherapy
. Fibrosarcoma; intermediate prognosis
. Osteosarcoma; very poor overall survival
. Giant cell tumor; benign but locally aggressive

Correct Answer & Explanation

. Osteosarcoma; very poor overall survival

Explanation

Malignant transformation in Paget's disease most commonly results in secondary osteosarcoma. It occurs in older patients and carries a dismal prognosis, with a 5-year survival rate typically less than 20% despite aggressive surgical and systemic therapy.

Question 706

Topic: 10. Pathology and Oncology

A 25-year-old female presents with a painless, slowly enlarging mass on the posterior aspect of her distal femur. Radiographs reveal a densely ossified, broad-based surface lesion with no medullary involvement. Histology demonstrates low-grade spindle cells intermixed with parallel trabeculae of woven bone. Amplification of which of the following genes is classically associated with this tumor?

. MDM2
. GNAS
. EXT1
. RB1
. TP53

Correct Answer & Explanation

. MDM2

Explanation

This clinical and histologic picture describes a parosteal osteosarcoma, a low-grade surface osteosarcoma. It is classically associated with the amplification of the MDM2 and CDK4 genes on chromosome 12q13-15.

Question 707

Topic: 10. Pathology and Oncology

A 10-year-old boy presents for an evaluation of a minor ankle sprain. Radiographs reveal an incidental 2 cm eccentric, multilocular radiolucency with a well-defined sclerotic margin in the distal tibial metaphysis. He is completely asymptomatic in this area. What is the most appropriate next step in management?

. Curettage and bone grafting
. Core needle biopsy
. Observation with reassuring the parents
. Wide local excision
. Radiofrequency ablation

Correct Answer & Explanation

. Observation with reassuring the parents

Explanation

The lesion is a classic non-ossifying fibroma (NOF), which is typically an incidental finding in children. Asymptomatic, small lesions require only observation and reassurance, as they will spontaneously regress and ossify with skeletal maturity.

Question 708

Topic: 10. Pathology and Oncology

A 65-year-old male with a long-standing history of mild thigh pain presents with acute worsening of symptoms. Radiographs of the proximal femur demonstrate a distinct bimorphic pattern: a central area of "popcorn" calcification surrounded by an aggressive, poorly marginated lytic destructive region. What is the most likely diagnosis?

. Mesenchymal chondrosarcoma
. Clear cell chondrosarcoma
. Dedifferentiated chondrosarcoma
. Telangiectatic osteosarcoma
. Secondary osteosarcoma

Correct Answer & Explanation

. Dedifferentiated chondrosarcoma

Explanation

Dedifferentiated chondrosarcoma is characterized by a low-grade cartilage tumor adjacent to a high-grade, non-cartilaginous sarcoma (often osteosarcoma or undifferentiated pleomorphic sarcoma). The classic bimorphic radiographic appearance is a heavily calcified enchondroma/low-grade chondrosarcoma abruptly transitioning into an aggressive lytic lesion.

Question 709

Topic: Bone Tumors

A 15-year-old boy presents with severe knee pain. MRI of the distal femur shows a destructive metaphyseal lesion with multiple fluid-fluid levels, mimicking an aneurysmal bone cyst. Biopsy reveals highly pleomorphic cells producing delicate lace-like osteoid in the septa. Which of the following is true regarding this variant of osteosarcoma compared to conventional osteosarcoma?

. It has a substantially worse prognosis and overall survival rate.
. It is managed primarily with wide resection without the need for neoadjuvant chemotherapy.
. It presents with similar overall survival and is treated with identical modern multimodal protocols.
. It predominantly affects patients over the age of 40.
. It is characterized by the t(11;22) chromosomal translocation.

Correct Answer & Explanation

. It presents with similar overall survival and is treated with identical modern multimodal protocols.

Explanation

Telangiectatic osteosarcoma frequently mimics an aneurysmal bone cyst on imaging due to fluid-fluid levels. Despite its aggressive radiographic appearance, when treated with standard modern chemotherapy and wide resection, its prognosis and overall survival are similar to conventional osteosarcoma.

Question 710

Topic: 10. Pathology and Oncology

A 40-year-old male presents with chronic hip pain. Radiographs reveal a purely lytic, well-circumscribed epiphyseal lesion in the proximal femur. Biopsy demonstrates uniform cells with abundant clear cytoplasm and central nuclei, interspersed with areas of conventional low-grade chondrosarcoma and woven bone. What is the diagnosis?

. Chondroblastoma
. Clear cell chondrosarcoma
. Giant cell tumor
. Metastatic renal cell carcinoma
. Chondromyxoid fibroma

Correct Answer & Explanation

. Clear cell chondrosarcoma

Explanation

Clear cell chondrosarcoma classically presents as a lytic epiphyseal lesion in adults (often mimicking a chondroblastoma, which typically occurs in younger patients with open physes). Histology shows characteristic cells with clear cytoplasm (due to glycogen) alongside conventional cartilage.

Question 711

Topic: 10. Pathology and Oncology

In a 14-year-old patient newly diagnosed with conventional high-grade osteosarcoma of the distal femur, which of the following is the single most significant prognostic factor for long-term survival at the time of presentation?

. Degree of histologic response to chemotherapy
. Presence of macroscopic distant metastasis
. Tumor size greater than 8 cm
. Elevated serum alkaline phosphatase
. Extensive extraosseous soft tissue extension

Correct Answer & Explanation

. Presence of macroscopic distant metastasis

Explanation

The presence of macroscopic distant metastasis at the time of diagnosis is the most important prognostic factor in osteosarcoma, dropping the survival rate to approximately 20-30%. In localized disease, the percentage of tumor necrosis following neoadjuvant chemotherapy is the most critical prognostic indicator.

Question 712

Topic: Bone Tumors
A 12-year-old boy is evaluated for multiple non-ossifying fibromas in his lower extremities. Physical examination reveals several café-au-lait spots with smooth margins, axillary freckling, and mild intellectual disability. Which of the following conditions is most consistent with this presentation?
. Neurofibromatosis type 1
. McCune-Albright syndrome
. Jaffe-Campanacci syndrome
. Mazabraud syndrome
. Ollier disease

Correct Answer & Explanation

. Jaffe-Campanacci syndrome

Explanation

Jaffe-Campanacci syndrome is characterized by multiple non-ossifying fibromas (NOFs), café-au-lait spots, mental retardation, hypogonadism, and cardiovascular abnormalities. The café-au-lait spots can mimic those seen in Neurofibromatosis type 1.

Question 713

Topic: Bone Tumors

A 55-year-old male is diagnosed with a conventional Grade II chondrosarcoma of the ilium. Compared to an identical histologic lesion located in the distal femur, what is the primary reason this pelvic lesion portends a significantly poorer prognosis?

. Higher likelihood of early hematogenous pulmonary metastasis
. Increased intrinsic cellular resistance to systemic chemotherapy
. Difficulty in achieving wide and adequate surgical margins
. Higher rate of spontaneous dedifferentiation in flat bones
. Tendency to spread to regional lymph nodes early in the disease course

Correct Answer & Explanation

. Difficulty in achieving wide and adequate surgical margins

Explanation

Chondrosarcomas of the pelvis typically have a worse prognosis than those in the appendicular skeleton primarily because they grow to a massive size before becoming symptomatic and involve complex anatomy, making wide surgical margins difficult to achieve.

Question 714

Topic: 10. Pathology and Oncology

A 19-year-old male presents with localized pain over the anterior tibial diaphysis. Imaging reveals a radiolucent surface lesion causing cortical saucerization and a "hair-on-end" perpendicular periosteal reaction. There is no intramedullary involvement. Biopsy shows a high-grade chondroblastic matrix with fine, lace-like osteoid production. What is the most likely diagnosis?

. Parosteal osteosarcoma
. Periosteal osteosarcoma
. Periosteal chondroma
. High-grade surface osteosarcoma
. Ewing sarcoma

Correct Answer & Explanation

. Periosteal osteosarcoma

Explanation

Periosteal osteosarcoma is an intermediate-grade surface tumor predominantly found on the diaphysis of the tibia or femur. It classically causes cortical saucerization, perpendicular periosteal reactions, and is predominantly chondroblastic on histology.

Question 715

Topic: 10. Pathology and Oncology

Genetic analysis of a central conventional chondrosarcoma is most likely to reveal a somatic mutation in which of the following genes?

. EXT1
. IDH1
. GNAS
. TP53
. MDM2

Correct Answer & Explanation

. IDH1

Explanation

Somatic mutations in the IDH1 or IDH2 (isocitrate dehydrogenase) genes are found in over 50% of conventional central chondrosarcomas and enchondromas. EXT1/EXT2 mutations are associated with osteochondromas.

Question 716

Topic: 10. Pathology and Oncology

Which of the following best describes the classic histologic appearance of a non-ossifying fibroma (NOF)?

. Bland spindle cells arranged in a storiform pattern with scattered multinucleated giant cells and lipid-laden foam cells
. Sheets of uniform round cells with distinct cytoplasmic borders and "chicken-wire" calcification
. Highly pleomorphic spindle cells producing delicate, lace-like osteoid matrix
. A biphasic tumor demonstrating islands of benign-appearing hyaline cartilage within a high-grade spindle cell component
. Benign cartilage lobules encased in a thick rim of mature lamellar bone

Correct Answer & Explanation

. Bland spindle cells arranged in a storiform pattern with scattered multinucleated giant cells and lipid-laden foam cells

Explanation

The histology of a non-ossifying fibroma consists of benign spindle cells in a distinct "storiform" (cartwheel/whirling) pattern, intermixed with multinucleated giant cells, lipid-laden macrophages (foam cells), and hemosiderin pigment.

Question 717

Topic: 10. Pathology and Oncology

A 72-year-old male with a long-standing history of Paget's disease of bone presents with acutely worsening pain and a rapidly enlarging mass in his right humerus. Radiographs show a new, destructive, bone-forming lesion with cortical breakthrough. What is the most likely diagnosis and its typical prognosis?

. Conventional chondrosarcoma with an excellent prognosis after wide excision
. Secondary osteosarcoma with a very poor prognosis
. Dedifferentiated chondrosarcoma with a poor prognosis
. Metastatic prostate cancer with an intermediate prognosis
. Osteofibrous dysplasia with an excellent prognosis

Correct Answer & Explanation

. Secondary osteosarcoma with a very poor prognosis

Explanation

Secondary osteosarcoma most frequently occurs in the setting of Paget's disease or prior radiation therapy. It occurs in older adults and carries a notoriously poor prognosis compared to primary conventional osteosarcoma.

Question 718

Topic: Bone Tumors

The standard neoadjuvant chemotherapy regimen (MAP) utilized for high-grade conventional osteosarcoma in pediatric and young adult patients typically consists of which combination of agents?

. Vincristine, doxorubicin, and cyclophosphamide
. Methotrexate, doxorubicin, and cisplatin
. Ifosfamide and etoposide
. Imatinib and sunitinib
. Denosumab and zoledronic acid

Correct Answer & Explanation

. Methotrexate, doxorubicin, and cisplatin

Explanation

The MAP regimen consists of high-dose Methotrexate, doxorubicin (Adriamycin), and Cisplatin. It is the gold standard neoadjuvant and adjuvant chemotherapy protocol for conventional high-grade osteosarcoma.

Question 719

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a destructive soft-tissue and bony mass in the jaw. Histological examination reveals a distinctive biphasic pattern consisting of highly cellular sheets of undifferentiated small round blue cells interspersed with distinct islands of well-differentiated, benign-appearing hyaline cartilage. What is the most likely diagnosis?

. Clear cell chondrosarcoma
. Dedifferentiated chondrosarcoma
. Mesenchymal chondrosarcoma
. Chondroblastic osteosarcoma
. Ewing sarcoma

Correct Answer & Explanation

. Mesenchymal chondrosarcoma

Explanation

Mesenchymal chondrosarcoma is an aggressive variant that frequently involves the jaw or axial skeleton. Its hallmark histologic feature is a biphasic pattern of undifferentiated small round blue cells alternating with well-differentiated islands of hyaline cartilage.

Question 720

Topic: 10. Pathology and Oncology

A 16-year-old boy is diagnosed with a high-grade conventional osteosarcoma of the proximal tibia. As part of his local staging, a non-contrast T1-weighted MRI of the entire tibia is obtained. What is the primary purpose of imaging the entire involved bone rather than just the joint and tumor?

. To evaluate for microscopic neurovascular bundle invasion
. To assess the degree of tumor necrosis prior to biopsy
. To identify intramedullary skip metastases within the same bone
. To measure extraosseous soft tissue extension precisely
. To definitively rule out overlying muscle involvement

Correct Answer & Explanation

. To identify intramedullary skip metastases within the same bone

Explanation

Skip metastases are discrete secondary foci of the tumor located within the same long bone as the primary lesion, separated by normal marrow. Whole-bone MRI is mandatory in osteosarcoma staging to rule out skip lesions, as their presence alters the required resection level.

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