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10. Pathology and Oncology MCQs

Practice Set 44 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 861

Topic: 10. Pathology and Oncology

A 65-year-old woman with a history of breast cancer presents with moderate thigh pain. Radiographs show a 2.5 cm lytic lesion in the peritrochanteric region of the femur that occupies 70% of the cortical diameter. Which of the following factors contributes the most points to her Mirels' score for prophylactic fixation?

. Moderate pain
. History of breast cancer
. Size greater than 2/3 of the cortical diameter
. Lytic nature of the lesion
. Peritrochanteric location

Correct Answer & Explanation

. Size greater than 2/3 of the cortical diameter

Explanation

The Mirels' scoring system assesses the risk of pathologic fracture. A score of 3 (maximum points per category) is given for: severe pain, peritrochanteric location, lytic lesion, and size > 2/3 of the cortical diameter. All factors listed here (size, lytic nature, peritrochanteric location) contribute 3 points, making them equally the highest contributors.

Question 862

Topic: 10. Pathology and Oncology

A 60-year-old man sustains a pathologic subtrochanteric fracture. Biopsy confirms metastatic renal cell carcinoma. Before definitive surgical stabilization with an intramedullary nail, which intervention is most critical to perform?

. Neoadjuvant chemotherapy
. Preoperative selective arterial embolization
. External beam radiation therapy
. Intravenous bisphosphonate infusion
. Administration of denosumab

Correct Answer & Explanation

. Preoperative selective arterial embolization

Explanation

Metastases from renal cell carcinoma and thyroid carcinoma are highly vascular. Preoperative selective arterial embolization is critical to significantly reduce intraoperative blood loss and surgical morbidity during stabilization.

Question 863

Topic: 10. Pathology and Oncology

A 16-year-old male sustains a pathologic fracture through a biopsy-proven distal femur osteosarcoma. How does the presence of this fracture alter his prognosis and treatment options compared to a patient without a fracture?

. It is an absolute indication for immediate amputation
. It significantly decreases overall 5-year survival rates by 50%
. It precludes the use of neoadjuvant chemotherapy
. Limb salvage remains an option and overall survival is similar to non-fractured cases
. It requires immediate internal fixation prior to chemotherapy

Correct Answer & Explanation

. Limb salvage remains an option and overall survival is similar to non-fractured cases

Explanation

A pathologic fracture through an osteosarcoma was historically an indication for amputation. With modern chemotherapy, limb salvage can still be safely achieved in many patients without compromising overall survival.

Question 864

Topic: 10. Pathology and Oncology

A 32-year-old woman presents with a pathologic fracture of the proximal tibia through an expansile, lytic epiphyseal-metaphyseal lesion extending to subchondral bone. Biopsy shows a giant cell tumor. What medical therapy is indicated to facilitate future joint-salvage surgery?

. Imatinib mesylate
. Denosumab
. High-dose methotrexate
. Doxorubicin and cisplatin
. Zoledronic acid

Correct Answer & Explanation

. Denosumab

Explanation

Denosumab, a monoclonal antibody against RANKL, is highly effective in treating Giant Cell Tumor of bone. It induces intralesional ossification and a sclerotic rim, facilitating subsequent curettage and joint salvage in difficult or fractured cases.

Question 865

Topic: 10. Pathology and Oncology



A 45-year-old man presents with this painful destructive lesion of the distal femur. A core needle biopsy is planned. Which of the following is the most critical technical principle for the biopsy trajectory?

. It must be trans-articular to avoid the vastus medialis
. It must utilize a transverse incision to minimize tension
. It must be placed in line with the planned definitive surgical incision
. It should use a posterolateral approach to avoid neurovascular structures
. It must traverse multiple muscle compartments for adequate sampling

Correct Answer & Explanation

. It must be placed in line with the planned definitive surgical incision

Explanation

The biopsy tract must be placed in line with the planned longitudinal surgical incision. This ensures the entire potentially contaminated tract can be excised en bloc during definitive tumor resection.

Question 866

Topic: 10. Pathology and Oncology

A 55-year-old man presents with an enlarging mass in the right ilium. Radiographs reveal a large lytic lesion with "popcorn" intralesional calcifications. Biopsy confirms grade 2 chondrosarcoma. What is the mainstay of definitive treatment?

. Neoadjuvant chemotherapy followed by wide resection
. Definitive external beam radiation therapy
. Wide surgical resection alone
. Intralesional curettage, phenol, and cementation
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional intermediate and high-grade chondrosarcomas are notoriously resistant to both chemotherapy and radiation. Wide surgical resection is the primary and definitive treatment modality to achieve a cure.

Question 867

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with severe thigh pain after a minor football injury. Radiographs show a permeative diaphyseal lesion with an "onion-skin" periosteal reaction. Which of the following translocations is most characteristic of the likely diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. The t(11;22)(q24;q12) translocation, resulting in the EWS-FLI1 fusion protein, is found in approximately 85-90% of Ewing sarcoma cases.

Question 868

Topic: 10. Pathology and Oncology

A 25-year-old man presents with a hard mass in the posterior thigh, noticed 8 weeks after a blunt contusion. Radiographs show a soft tissue mass with dense peripheral ossification and a radiolucent center. What is the most appropriate management?

. Immediate wide en bloc resection
. Open incisional biopsy
. Observation and symptom-guided physical therapy
. Radiation therapy to prevent growth
. Neoadjuvant chemotherapy

Correct Answer & Explanation

. Observation and symptom-guided physical therapy

Explanation

The finding of peripheral ossification (zonal phenomenon) with a radiolucent center is diagnostic of myositis ossificans. This benign reactive process is managed non-operatively with observation, as it matures and often shrinks over time.

Question 869

Topic: 10. Pathology and Oncology

A 30-year-old man presents with a dull ache in his anterior leg. Radiographs reveal multiple, sharply circumscribed, eccentric lytic lesions with a "soap bubble" appearance in the anterior tibial diaphysis. What is the most likely diagnosis?

. Osteofibrous dysplasia
. Adamantinoma
. Paget's disease
. Ewing sarcoma
. Parosteal osteosarcoma

Correct Answer & Explanation

. Adamantinoma

Explanation

Adamantinoma is a rare, low-grade malignant bone tumor that characteristically occurs in the anterior tibial diaphysis of young adults. It typically presents with a "soap bubble" lytic appearance and requires wide local excision.

Question 870

Topic: 10. Pathology and Oncology

A 65-year-old woman treated with radiation for breast cancer 12 years ago presents with a new lytic lesion in her scapula. Biopsy shows high-grade pleomorphic sarcoma. According to Cahan's criteria for radiation-induced sarcoma, which of the following is required?

. It must be of the exact same histologic type as the primary treated tumor
. It must occur within 2 years of the radiation exposure
. It must arise within the field of previous radiation
. It must be treated with repeat radiation therapy
. It only occurs in the appendicular skeleton

Correct Answer & Explanation

. It must arise within the field of previous radiation

Explanation

Cahan's criteria for radiation-induced sarcoma require: history of radiation, tumor arises within the radiation field, a latent period of at least 3-4 years, and a distinct histology from the primary tumor.

Question 871

Topic: Bone Tumors



A 19-year-old runner presents with night pain in the thigh that dramatically improves with ibuprofen. Imaging reveals a 1 cm radiolucent nidus surrounded by thick cortical sclerosis. If conservative management fails, what is the preferred definitive treatment?

. Wide en bloc resection of the involved cortex
. Intra-arterial chemotherapy
. CT-guided radiofrequency ablation (RFA)
. Prophylactic intramedullary nailing
. External beam radiation

Correct Answer & Explanation

. CT-guided radiofrequency ablation (RFA)

Explanation

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

Question 872

Topic: Bone Tumors

A 70-year-old man presents with a pathologic humeral fracture. A skeletal survey reveals multiple "punched-out" lytic lesions, and labs confirm multiple myeloma. Which imaging modality is most critical for detecting impending spinal cord compression in this patient?

. Technetium-99m bone scan
. Total body MRI
. Positron emission tomography (PET) scan
. CT scan of the chest, abdomen, and pelvis
. Dual-energy X-ray absorptiometry (DEXA)

Correct Answer & Explanation

. Total body MRI

Explanation

In multiple myeloma, a bone scan is notoriously falsely negative (cold) due to purely osteoclastic activity without osteoblastic repair. Total body MRI is the gold standard for assessing marrow involvement and impending spinal cord compression.

Question 873

Topic: Bone Tumors

A 14-year-old girl presents with an eccentric, expansile, lytic lesion in the proximal tibia metaphysis after a fall. MRI demonstrates multiple fluid-fluid levels. What is the underlying genetic abnormality commonly associated with the primary form of this lesion?

. USP6 gene rearrangement
. GNAS1 mutation
. EXT1 mutation
. RB1 mutation
. TP53 mutation

Correct Answer & Explanation

. USP6 gene rearrangement

Explanation

Primary aneurysmal bone cysts (ABCs) are driven by a true neoplastic process, most frequently characterized by a t(16;17) translocation that causes upregulation of the USP6 gene.

Question 874

Topic: 10. Pathology and Oncology

A 50-year-old man presents with bilateral stress fractures of the lower extremities and profound muscle weakness. Labs show severe hypophosphatemia, normal calcium, and elevated FGF-23 levels. What is the most likely underlying pathology?

. Phosphaturic mesenchymal tumor
. Multiple myeloma
. Primary hyperparathyroidism
. Metastatic prostate cancer
. Renal cell carcinoma

Correct Answer & Explanation

. Phosphaturic mesenchymal tumor

Explanation

Tumor-induced osteomalacia is a paraneoplastic syndrome typically caused by a benign phosphaturic mesenchymal tumor secreting FGF-23. This causes renal phosphate wasting, leading to osteomalacia and multiple stress fractures.

Question 875

Topic: Bone Tumors

A 15-year-old boy presents with severe thigh pain primarily at night, which is relieved significantly by ibuprofen. Radiographs and the provided imaging demonstrate a small radiolucent nidus surrounded by dense reactive sclerosis in the proximal femur.

What is the most appropriate definitive management if non-operative measures fail?

. Wide surgical resection and allograft reconstruction
. Radiofrequency ablation (RFA)
. Neoadjuvant chemotherapy followed by curettage
. Radiation therapy
. Intralesional injection of corticosteroids

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical presentation and imaging are classic for an osteoid osteoma. If conservative management with NSAIDs fails, CT-guided radiofrequency ablation (RFA) is the minimally invasive treatment of choice with high success rates.

Question 876

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a permeative lytic lesion in the fibular diaphysis with an "onion-skin" periosteal reaction. Core biopsy reveals small, round, blue cells. Which specific chromosomal translocation is most characteristically associated with this tumor?

. t(X;18)(p11;q11)
. t(11;22)(q24;q12)
. t(12;16)(q13;p11)
. t(9;22)(q34;q11)
. t(2;13)(q35;q14)

Correct Answer & Explanation

. t(11;22)(q24;q12)

Explanation

The presentation is classic for Ewing sarcoma. The hallmark genetic abnormality is the t(11;22)(q24;q12) translocation, which creates the EWS-FLI1 fusion protein.

Question 877

Topic: Bone Tumors

A 55-year-old male is diagnosed with a grade 2 conventional chondrosarcoma of the proximal femur. Which of the following is the most appropriate definitive treatment?

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

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

Conventional chondrosarcomas are generally resistant to both chemotherapy and radiation. The standard of care for intermediate to high-grade (grade 2 and 3) chondrosarcoma is wide surgical excision with negative margins.

Question 878

Topic: 10. Pathology and Oncology

A 45-year-old female has an incidental finding of a cartilaginous lesion in the proximal humerus. Which radiographic feature is most suggestive of a low-grade chondrosarcoma rather than a benign enchondroma?

. Popcorn-like intralesional calcifications
. Location in the diaphysis
. Deep endosteal scalloping > 2/3 of the cortical thickness
. A narrow zone of transition
. Absence of periosteal reaction

Correct Answer & Explanation

. Deep endosteal scalloping > 2/3 of the cortical thickness

Explanation

Endosteal scalloping greater than two-thirds of the cortical thickness is a highly specific radiographic marker for chondrosarcoma. Benign enchondromas typically exhibit minimal to no endosteal scalloping.

Question 879

Topic: 10. Pathology and Oncology

A 62-year-old male with multiple myeloma presents with a painful lytic lesion in the proximal femur involving 70% of the cortical diameter. Pain increases with weight-bearing. According to the Mirels criteria, what is the most appropriate management?

. Observation and protected weight-bearing
. Primary radiation therapy without surgery
. Prophylactic intramedullary nailing
. Bisphosphonate therapy alone
. Curettage and cementation without internal fixation

Correct Answer & Explanation

. Prophylactic intramedullary nailing

Explanation

The Mirels score considers the site (lower limb=3), pain (functional=3), lesion type (lytic=3), and size (>2/3 cortex=3). A score of 8 or higher (this patient scores 12) indicates a high risk of pathologic fracture, mandating prophylactic internal fixation.

Question 880

Topic: 10. Pathology and Oncology

A 16-year-old female undergoes neoadjuvant chemotherapy followed by wide resection for a distal femur osteosarcoma. Which of the following histologic findings in the resected specimen is the most important prognostic factor for her overall survival?

. The degree of osteoid matrix production
. The mitotic rate of the residual tumor cells
. The percentage of tumor necrosis
. The presence of an intact pseudocapsule
. The histologic subtype (e.g., telangiectatic vs. conventional)

Correct Answer & Explanation

. The percentage of tumor necrosis

Explanation

The percentage of tumor necrosis following neoadjuvant chemotherapy is the most critical prognostic indicator in osteosarcoma. A good response is typically defined as greater than 90% tumor necrosis.

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