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10. Pathology and Oncology MCQs

Practice Set 54 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 1061

Topic: Bone Tumors

Which chemotherapy agent used in osteosarcoma treatment is associated with the risk of cardiotoxicity, particularly cumulative dose-dependent cardiomyopathy?

. Methotrexate
. Cisplatin
. Ifosfamide
. Doxorubicin
. Etoposide

Correct Answer & Explanation

. Doxorubicin

Explanation

Correct Answer: DDoxorubicin (Adriamycin) is a highly effective anthracycline antibiotic used in osteosarcoma regimens, but its main dose-limiting toxicity is cumulative, dose-dependent cardiotoxicity, leading to dilated cardiomyopathy and congestive heart failure. Lifelong monitoring of cardiac function is required, and the cumulative dose must be carefully managed. Methotrexate causes renal toxicity and mucositis. Cisplatin causes ototoxicity, nephrotoxicity, and neurotoxicity. Ifosfamide can cause hemorrhagic cystitis (prevented with Mesna) and neurotoxicity. Etoposide is associated with myelosuppression and mucositis.

Question 1062

Topic: 10. Pathology and Oncology

Which of the following factors would most strongly contraindicate limb salvage surgery and necessitate amputation for a distal femoral osteosarcoma?

. Tumor size greater than 10 cm
. Patient age less than 12 years
. Metastatic disease to the lungs
. Involvement of the sciatic nerve and femoral artery requiring their sacrifice
. Pathological fracture through the tumor

Correct Answer & Explanation

. Involvement of the sciatic nerve and femoral artery requiring their sacrifice

Explanation

Correct Answer: DExtensive involvement of the neurovascular bundle (e.g., sciatic nerve and femoral artery) requiring its sacrifice is a strong contraindication to limb salvage. Resecting these critical structures would lead to a non-functional limb or unsalvageable limb ischemia, making amputation the more functional and safer option. While tumor size >10 cm and pathological fracture can complicate limb salvage and increase local recurrence risk, they are not absolute contraindications. Metastatic disease to the lungs does not preclude limb salvage of the primary tumor, as systemic disease is treated systemically. Patient age <12 years is a challenge for limb length discrepancy but does not contraindicate limb salvage (e.g., with expandable prostheses or rotationplasty).

Question 1063

Topic: 10. Pathology and Oncology

A 65-year-old male with a long history of Paget's disease of the tibia develops increasing pain and a rapidly enlarging mass. Biopsy confirms osteosarcoma. What is the prognosis compared to conventional osteosarcoma in adolescents?

. Significantly better prognosis due to earlier detection in older patients.
. Similar prognosis, as age does not impact osteosarcoma outcomes.
. Worse prognosis due to older age, higher tumor grade, and often more advanced stage at presentation.
. Prognosis is entirely dependent on the primary site, not the age or underlying condition.
. Osteosarcoma in Paget's disease is typically low-grade with good response to chemotherapy.

Correct Answer & Explanation

. Worse prognosis due to older age, higher tumor grade, and often more advanced stage at presentation.

Explanation

Correct Answer: COsteosarcoma arising in Paget's disease (secondary osteosarcoma) generally carries a significantly worse prognosis compared to conventional osteosarcoma in adolescents. This is attributed to several factors: patients are older and may have more comorbidities, the tumors are often high-grade, tend to be larger, and are frequently diagnosed at an advanced stage (often with metastases). They also tend to respond less favorably to chemotherapy.

Question 1064

Topic: 10. Pathology and Oncology

A 9-year-old male presents with an incidental finding of a lucent lesion in the distal femur on radiographs obtained after a minor fall. The lesion is eccentric, lobulated, and has a well-defined sclerotic rim, as shown in the image below. He is asymptomatic. Which of the following statements regarding the natural history of this likely diagnosis is most accurate?

. It typically progresses to an aggressive osteosarcoma in adulthood.
. It often spontaneously resolves by skeletal maturity, with osseous remodeling.
. Surgical excision is always indicated due to high risk of malignant transformation.
. It is a precursor lesion to Paget's disease of bone.
. It commonly recurs after surgical curettage.

Correct Answer & Explanation

. It often spontaneously resolves by skeletal maturity, with osseous remodeling.

Explanation

Correct Answer: BNon-ossifying fibroma (NOF) is a benign, self-limiting fibrous lesion that characteristically regresses spontaneously, often filling in with normal bone by skeletal maturity. This process is known as osseous remodeling. Malignant transformation is exceedingly rare to non-existent, making options A and C incorrect. Surgical excision is not always indicated and is reserved for specific situations like impending or actual pathological fracture. It is not a precursor to osteosarcoma or Paget's disease (option D), and recurrence after complete curettage is uncommon (option E).

Question 1065

Topic: 10. Pathology and Oncology

A biopsy from a well-circumscribed, eccentrically located metaphyseal lesion in a 12-year-old child reveals spindle cells arranged in a storiform pattern, admixed with multinucleated giant cells and hemosiderin deposition. Which of the following microscopic features would be LEAST characteristic of this lesion?

. Spindle cell proliferation in a storiform pattern.
. Scattered multinucleated giant cells.
. Presence of foam cells (lipid-laden macrophages).
. Production of osteoid and woven bone trabeculae.
. Hemosiderin deposition.

Correct Answer & Explanation

. Production of osteoid and woven bone trabeculae.

Explanation

Correct Answer: DThe classic histological description of a non-ossifying fibroma (NOF) includes a proliferation of benign spindle cells, often arranged in a storiform (pinwheel or cartwheel) pattern, admixed with scattered multinucleated giant cells, foam cells (lipid-laden macrophages), and areas of hemosiderin deposition. These features correspond to options A, B, C, and E. However, NOFs are fibrous lesions and do not typically produce osteoid or woven bone trabeculae. The presence of osteoid and woven bone would be characteristic of osteoid osteoma, osteoblastoma, or fibrous dysplasia, making option D the least characteristic feature of an NOF.

Question 1066

Topic: Bone Tumors

A 10-year-old girl with a known Non-Ossifying Fibroma (NOF) in the distal tibia is scheduled for a follow-up radiograph in 6 months. Her initial radiograph is shown. What radiographic finding would indicate the lesion is entering its 'healing' or 'latent' phase?

. Increased size and further cortical thinning.
. Development of new periosteal reaction.
. Increased central sclerosis and gradual filling in of the lucency.
. Development of fluid-fluid levels.
. Soft tissue mass formation adjacent to the lesion.

Correct Answer & Explanation

. Increased central sclerosis and gradual filling in of the lucency.

Explanation

Correct Answer: CThe 'healing' or 'latent' phase of a Non-Ossifying Fibroma is characterized by a gradual increase in central sclerosis, with the lesion becoming denser and eventually filling in with normal bone. The lesion typically shrinks, and the lucent area is replaced by opaque bone. Increased size and cortical thinning (option A) would suggest continued activity or growth. Development of new periosteal reaction (option B) or soft tissue mass formation (option E) would be atypical for a healing NOF and raise concern for other pathologies or complications like fracture. Fluid-fluid levels (option D) are characteristic of aneurysmal bone cysts, not NOFs.

Question 1067

Topic: 10. Pathology and Oncology

A 7-year-old child has routine X-rays following a minor ankle sprain, revealing an incidental, well-defined, lytic lesion with a sclerotic rim in the distal tibial metaphysis. The lesion measures 2 cm in its greatest dimension and appears purely cortical. The child is asymptomatic. What is the most appropriate initial management?

. Immediate curettage and bone grafting.
. Prophylactic internal fixation.
. Serial radiographic observation.
. Biopsy to rule out malignancy.
. Radiation therapy.

Correct Answer & Explanation

. Serial radiographic observation.

Explanation

Correct Answer: CFor small (typically <2-3 cm), asymptomatic non-ossifying fibromas (often referred to as fibrous cortical defects when purely cortical), the most appropriate initial management is serial radiographic observation. These lesions are benign and often regress spontaneously. Surgical intervention (curettage, grafting) is reserved for larger lesions (typically >50% cortical involvement), symptomatic lesions, or those with pathological fracture risk. Biopsy is generally not needed if characteristic radiographic features are present in the appropriate age group. Radiation therapy is contraindicated for benign bone lesions.

Question 1068

Topic: 10. Pathology and Oncology

A 14-year-old competitive soccer player sustains a pathological fracture through a 6 cm Non-Ossifying Fibroma located in the distal femoral metaphysis. The lesion involves approximately 60% of the cortical circumference, as depicted in the radiograph. After initial immobilization and stabilization of the fracture, what is the most appropriate definitive next step in management?

. Continued conservative management with cast immobilization until union.
. Open biopsy followed by aggressive chemotherapy.
. Intralesional steroid injection.
. Curettage and bone grafting, with or without internal fixation.
. Amputation.

Correct Answer & Explanation

. Curettage and bone grafting, with or without internal fixation.

Explanation

Correct Answer: DA pathological fracture through a large non-ossifying fibroma (NOF), especially one involving more than 50% of the cortex, is a clear indication for surgical intervention. While conservative management might be considered for small, non-displaced fractures through very small lesions, a 6 cm lesion with 60% cortical involvement and a fracture warrants curettage and bone grafting. Internal fixation may be added to provide stability and protect the construct, especially in a young, active individual. Chemotherapy and amputation are inappropriate for a benign lesion. Intralesional steroids are used for other benign lesions like unicameral bone cysts, not NOF.

Question 1069

Topic: Bone Tumors

A 12-year-old boy presents with a large, expansile, lytic metaphyseal lesion in the proximal tibia. An MRI is performed to further characterize the lesion. Which of the following features on the MRI would *strongly suggest* a diagnosis *other than* Non-Ossifying Fibroma?

. Eccentric cortical location.
. Well-defined sclerotic rim.
. Fluid-fluid levels on T2-weighted MRI.
. Multiloculated appearance.
. Cortical thinning.

Correct Answer & Explanation

. Fluid-fluid levels on T2-weighted MRI.

Explanation

Correct Answer: CFluid-fluid levels on MRI are highly characteristic of an Aneurysmal Bone Cyst (ABC) and are typically not seen in a Non-Ossifying Fibroma. While NOFs can be eccentric (option A), have a sclerotic rim (option B), appear multiloculated (option D), and cause cortical thinning (option E), the presence of fluid-fluid levels would strongly point away from an NOF and towards an ABC or other cystic/hemorrhagic lesion. Differentiating NOF from ABC is crucial as their management strategies can differ, especially for large or symptomatic lesions.

Question 1070

Topic: Bone Tumors

A 7-year-old child presents with a well-defined, asymptomatic lesion on a radiograph of the distal femur. The lesion is cortical-based, eccentrically located, and appears lucent with a sclerotic rim, measuring 1.5 cm in its greatest dimension. Which term is most accurately used to describe this small, purely cortical lesion with these features?

. Unicameral Bone Cyst
. Aneurysmal Bone Cyst
. Fibrous Cortical Defect
. Osteoid Osteoma
. Chondromyxoid Fibroma

Correct Answer & Explanation

. Fibrous Cortical Defect

Explanation

Correct Answer: CA small, purely cortical, asymptomatic non-ossifying fibroma is often referred to as a fibrous cortical defect (FCD). FCDs are essentially smaller versions of NOFs, sharing the same histological and radiographic characteristics, but are typically less than 2-3 cm and confined to the cortex. They are very common, found in up to 30-40% of children. Unicameral bone cysts and aneurysmal bone cysts are typically medullary and often larger. Osteoid osteoma has a characteristic nidus and often causes night pain relieved by NSAIDs. Chondromyxoid fibroma is a distinct cartilaginous tumor.

Question 1071

Topic: Bone Tumors

A 13-year-old boy has an asymptomatic 5 cm Non-Ossifying Fibroma of the proximal tibia, incidentally discovered on radiographs. The lesion involves approximately 60% of the cortical circumference, as shown in the image. What is the most critical factor guiding surgical intervention in this case?

. Patient's preference for early return to sports.
. The exact location (e.g., weight-bearing area).
. The presence of a visible fluid-fluid level on MRI.
. Elevated serum calcium levels.
. The percentage of cortical involvement by the lesion.

Correct Answer & Explanation

. The percentage of cortical involvement by the lesion.

Explanation

Correct Answer: EThe size of the NOF and, more importantly, its involvement of the cortical bone (typically >50% of the cortical diameter or a lesion >2 cm in diameter in a weight-bearing bone) are the most critical factors determining the risk of pathological fracture and, consequently, the need for surgical intervention. A lesion involving 60% of the cortical circumference significantly weakens the bone, placing it at high risk for fracture. While the exact location (option B) is relevant (weight-bearing bones are higher risk), thepercentage of cortical involvementis the direct measure of structural weakening. Patient preference (option A) is considered but not the primary medical factor. Fluid-fluid levels (option C) suggest an ABC, not an NOF. Elevated calcium (option D) is irrelevant for NOF.

Question 1072

Topic: 10. Pathology and Oncology
A 12-year-old girl with a biopsy-proven non-ossifying fibroma of the distal tibia (40% cortical involvement, asymptomatic) presents with multiple similar lesions throughout the skeleton and several café-au-lait spots on her trunk. Which syndrome should be considered in this patient?
. Neurofibromatosis Type 1
. McCune-Albright Syndrome
. Jaffe-Campanacci Syndrome
. Ollier Disease
. Maffucci Syndrome

Correct Answer & Explanation

. Jaffe-Campanacci Syndrome

Explanation

The constellation of multiple non-ossifying fibromas and café-au-lait spots is highly suggestive of Jaffe-Campanacci Syndrome. This rare condition can also be associated with other extraskeletal manifestations such as mental retardation, hypogonadism, and ocular abnormalities.

Question 1073

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive knee pain. Radiographs reveal a mixed lytic and blastic lesion in the distal femoral metaphysis with periosteal elevation. Biopsy confirms high-grade osteosarcoma. What is the most appropriate next step in management?

. Amputation
. Neoadjuvant chemotherapy followed by wide resection
. Wide resection followed by adjuvant chemotherapy
. Isolated wide resection
. Radiation therapy followed by wide resection

Correct Answer & Explanation

. Neoadjuvant chemotherapy followed by wide resection

Explanation

The standard of care for high-grade osteosarcoma is neoadjuvant chemotherapy, followed by wide surgical resection, and then adjuvant chemotherapy. This approach allows for assessment of tumor necrosis, which is the most important prognostic factor. Osteosarcoma is generally radioresistant.

Question 1074

Topic: 10. Pathology and Oncology

A 55-year-old male presents with a large, painful mass in his right pelvis. Imaging shows a 10 cm multilobulated lesion with "ring and arc" calcifications arising from the ilium. Biopsy confirms grade 2 chondrosarcoma. What is the most appropriate treatment?

. Neoadjuvant chemotherapy followed by wide resection
. Wide surgical resection alone
. Intralesional curettage with cementation
. Definitive radiation therapy
. Bisphosphonate therapy and observation

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Chondrosarcomas are largely resistant to both chemotherapy and radiation therapy. The mainstay of treatment for intermediate to high-grade (Grade 2 or 3) chondrosarcoma is wide surgical resection alone to achieve negative margins.

Question 1075

Topic: 10. Pathology and Oncology

A 12-year-old girl presents with a permeative lytic lesion in her femoral diaphysis with "onion skin" periosteal reaction. Histology shows small round blue cells. Which of the following genetic translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is classically associated with the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein. It presents as a diaphyseal lesion with onion skinning and small round blue cells testing positive for CD99.

Question 1076

Topic: 10. Pathology and Oncology

A 62-year-old female with breast cancer presents with moderate thigh pain. Radiographs show a lytic lesion in the peritrochanteric femur involving 75% of the cortex diameter. What is her Mirels score and appropriate management?

. Score 7, radiation therapy alone
. Score 8, cast immobilization
. Score 9, bisphosphonates alone
. Score 11, prophylactic internal fixation
. Score 12, wide resection and endoprosthesis

Correct Answer & Explanation

. Score 11, prophylactic internal fixation

Explanation

Mirels criteria assigns points for site (peritrochanteric=3), pain (moderate=2), lesion type (lytic=3), and size (>2/3 of cortex=3). The total score is 11. A score of 9 or greater indicates a high risk of impending fracture, warranting prophylactic internal fixation.

Question 1077

Topic: Bone Tumors

A 19-year-old male reports persistent right thigh pain that is worse at night and dramatically relieved by ibuprofen. CT imaging reveals a 1 cm radiolucent nidus surrounded by dense sclerotic bone in the femoral diaphysis. What is the treatment of choice if conservative management fails?

. Wide surgical excision
. Intralesional curettage and bone grafting
. Radiofrequency ablation (RFA)
. Neoadjuvant chemotherapy followed by excision
. External beam radiation

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. If medical management with NSAIDs fails or is poorly tolerated, CT-guided radiofrequency ablation (RFA) is the standard, minimally invasive treatment of choice.

Question 1078

Topic: Bone Tumors

A 70-year-old male presents with generalized bone pain, fatigue, and renal insufficiency. Radiographs reveal multiple "punched-out" lytic lesions in his skull and pelvis. Laboratory tests show a monoclonal spike on serum protein electrophoresis. Which of the following is the most sensitive imaging modality for detecting skeletal involvement in this condition?

. Technetium-99m whole-body bone scan
. Plain radiograph skeletal survey
. Low-dose whole-body CT or PET/CT
. MRI of the complete spine only
. Dual-energy X-ray absorptiometry (DEXA)

Correct Answer & Explanation

. Low-dose whole-body CT or PET/CT

Explanation

Multiple myeloma lesions are purely lytic with little to no osteoblastic response, making Technetium-99m bone scans notoriously false-negative. Low-dose whole-body CT or PET/CT is currently the most sensitive modality for detecting skeletal manifestations of multiple myeloma.

Question 1079

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive distal thigh pain. Radiographs reveal a destructive metaphyseal lesion with a 'sunburst' periosteal reaction and a Codman triangle. Biopsy confirms high-grade, intramedullary osteosarcoma. What is the standard sequence of treatment?

. Primary surgical amputation
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Wide surgical resection followed by definitive radiation therapy
. Neoadjuvant radiation therapy, surgical resection, and adjuvant chemotherapy
. Definitive radiation therapy and systemic immunotherapy

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

High-grade intramedullary osteosarcoma is conventionally treated with neoadjuvant chemotherapy, followed by wide surgical resection and adjuvant chemotherapy. The percentage of tumor necrosis following neoadjuvant chemotherapy is one of the most important prognostic factors.

Question 1080

Topic: 10. Pathology and Oncology

A 12-year-old girl presents with a diaphyseal mass in her femur. Biopsy reveals sheets of small round blue cells. Cytogenetic testing demonstrates a t(11;22) translocation. Which fusion gene product is most likely responsible for this tumor's pathogenesis?

. SYT-SSX
. EWS-FLI1
. TLS-CHOP
. PAX3-FKHR
. COL1A1-PDGFB

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is characterized by the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein. This drives neoplastic transformation in the bone diaphysis of pediatric patients.

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