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10. Pathology and Oncology MCQs

Practice Set 126 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 2501

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain. Radiographs reveal an aggressive, purely lytic lesion in the distal femoral metaphysis. MRI demonstrates multiple fluid-fluid levels within the lesion. Core needle biopsy shows large, blood-filled cystic spaces with septa containing highly pleomorphic, spindle-shaped cells producing fine, lace-like osteoid. What is the most likely diagnosis?

. Aneurysmal bone cyst
. Giant cell tumor of bone
. Telangiectatic osteosarcoma
. Simple bone cyst
. Ewing sarcoma

Correct Answer & Explanation

. Telangiectatic osteosarcoma

Explanation

The presence of a purely lytic lesion with fluid-fluid levels strongly suggests a differential of Aneurysmal Bone Cyst (ABC) or Telangiectatic Osteosarcoma. The key distinguishing feature on histology is the presence of malignant, pleomorphic cells producing lace-like osteoid in the septa, which is diagnostic for Telangiectatic Osteosarcoma.

Question 2502

Topic: 10. Pathology and Oncology

A 45-year-old female undergoes a wide resection of a proximal tibial tumor. Histologic examination reveals a cartilaginous matrix with plump nuclei, binucleate cells, and myxoid changes permeating through trabecular bone. What is the most appropriate adjuvant therapy following negative wide surgical margins?

. Methotrexate, Doxorubicin, and Cisplatin (MAP) chemotherapy
. Local external beam radiation
. No adjuvant therapy is typically indicated
. Denosumab therapy
. Radiofrequency ablation

Correct Answer & Explanation

. No adjuvant therapy is typically indicated

Explanation

The histologic description is classic for a conventional chondrosarcoma. Conventional chondrosarcomas are notably resistant to both chemotherapy and radiation therapy. The mainstay and only definitive treatment is wide surgical excision. Adjuvant therapy is typically not indicated.

Question 2503

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a painful diaphyseal femur lesion with an 'onion skin' periosteal reaction on radiographs. Core needle biopsy demonstrates small round blue cells that are strongly CD99 positive. Which of the following cytogenetic abnormalities is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation, creating the EWS-FLI1 fusion protein. t(X;18) is associated with synovial sarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(12;16) is associated with myxoid liposarcoma. t(9;22) is found in extraskeletal myxoid chondrosarcoma.

Question 2504

Topic: 10. Pathology and Oncology

A 16-year-old male is diagnosed with high-grade intramedullary osteosarcoma of the distal femur. Following 10 weeks of neoadjuvant multi-agent chemotherapy, he undergoes wide surgical resection. Pathological examination of the resected specimen is performed. Which of the following findings is the most significant prognostic indicator for long-term overall survival in this patient?

. Clearance of surgical margins by at least 5 centimeters
. The presence of highly atypical mitotic figures
. Greater than 90% tumor necrosis in the resected specimen
. Complete absence of vascular invasion
. Downstaging of the tumor from Enneking Stage IIB to IIA

Correct Answer & Explanation

. Greater than 90% tumor necrosis in the resected specimen

Explanation

In the management of osteosarcoma, the degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for long-term survival. According to the Huvos grading system, a 'good response' is defined as >90% tumor necrosis, which correlates with significantly improved disease-free and overall survival.

Question 2505

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slowly enlarging, painless mass deep in the soft tissues of his right thigh. Imaging reveals a juxta-articular soft tissue mass with punctate calcifications. Core needle biopsy demonstrates a biphasic pattern of spindle cells and epithelial cells. Molecular testing reveals a t(X;18)(p11;q11) chromosomal translocation. What is the diagnosis?

. Alveolar soft part sarcoma
. Ewing sarcoma
. Synovial sarcoma
. Clear cell sarcoma
. Liposarcoma

Correct Answer & Explanation

. Synovial sarcoma

Explanation

Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, which creates the SYT-SSX fusion gene. Clinically, it often presents in young adults as a slow-growing, deep mass near a joint (though rarely intra-articular) and is one of the few soft tissue sarcomas that frequently exhibits calcifications on plain radiographs (in up to 30% of cases). It can be monophasic (spindle cells only) or biphasic (spindle and epithelial cells).

Question 2506

Topic: 10. Pathology and Oncology

A 33-year-old man reports an enlarging painful soft-tissue mass in his right forearm. A radiograph and MRI scans are shown in Figures 45a through 45c. Treatment should consist of

. core biopsy.
. wide resection.
. radiation therapy.
. marginal resection.
. incisional biopsy.

Correct Answer & Explanation

. marginal resection.

Explanation

An intramuscular lipoma is a benign soft-tissue lesion that can grow and has a small risk of progressing to a liposarcoma. Radiographs usually show a globular radiolucent mass adjacent to higher-density muscle tissue shadows. When the patient has symptoms and reports an increase in size of the mass, the treatment of choice after appropriate radiographic analysis is complete excision of the mass with marginal resection. Sampling error is a problem with fatty lesions and core or incisional biopsies are frequently unnecessary, especially if an MRI scan of the lesion shows signal intensity that matches subcutaneous fat on all sequences. Damron TA: What to do with deep lipomatous tumors. Instr Course Lect 2004;53:651-655. Gaskin CM, Helms CA: Lipomas, lipoma variants, and well-differentiated liposarcomas (atypical lipomas): Results of MRI evaluations of 126 consecutive fatty masses. Am J Roentgenol 2004;182:733-739.

Question 2507

Topic: 10. Pathology and Oncology

A 66-year-old man has a high-grade angiosarcoma of the right tibia. A radiograph is shown in Figure 43. Treatment should consist of

. amputation.
. wide resection.
. radical resection.
. radiation therapy.
. chemotherapy.

Correct Answer & Explanation

. amputation.

Explanation

Angiosarcoma is a locally aggressive sarcoma. The radiograph shows extensive multiple discontinuous lesions throughout the entire tibia. The extent of bone involvement precludes resection; therefore, the treatment of choice is amputation, either above the knee or through the knee. Radiation therapy is not needed after amputation, and chemotherapy remains investigational for soft-tissue sarcoma.

Question 2508

Topic: 10. Pathology and Oncology
A 19-year-old male presents with persistent knee pain. Radiographs demonstrate a large, ill-defined, mixed lytic and sclerotic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms high-grade, conventional intramedullary osteosarcoma. He undergoes neoadjuvant chemotherapy followed by wide surgical resection. Pathologic examination of the resected specimen reveals 95% tumor necrosis. What is the primary clinical significance of this pathologic finding?
. It mandates the immediate performance of a limb amputation
. It indicates a high likelihood of concurrent skip metastases
. It is the single most important prognostic factor for overall survival
. It suggests the initial biopsy was a misdiagnosis and confirms Ewing sarcoma
. It warrants the complete discontinuation of postoperative adjuvant chemotherapy

Correct Answer & Explanation

. It is the single most important prognostic factor for overall survival

Explanation

The histologic response to neoadjuvant chemotherapy, quantified by the percentage of tumor necrosis in the resected specimen (Huvos grading system), is the most important prognostic indicator for overall and disease-free survival in patients with osteosarcoma. A good response is typically defined as ≥90% tumor necrosis. Despite a good response, adjuvant chemotherapy is still indicated to treat microscopic systemic disease.

Question 2509

Topic: 10. Pathology and Oncology
A 16-year-old boy is diagnosed with high-grade conventional osteosarcoma of the distal femur without pulmonary metastases. He receives neoadjuvant chemotherapy, undergoes wide local excision, and the tumor necrosis rate in the resected specimen is found to be 95%. Which of the following represents the most significant prognostic factor for long-term survival in this patient?
. Histologic subtype (e.g., osteoblastic vs. chondroblastic)
. The use of a cemented versus cementless endoprosthesis
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Size of the original tumor
. Level of serum alkaline phosphatase

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The percentage of tumor necrosis in response to neoadjuvant chemotherapy is one of the most critical prognostic factors for long-term survival in patients with high-grade, non-metastatic osteosarcoma. A good histologic response is typically defined as ≥ 90% tumor necrosis and is associated with significantly better overall survival compared to a poor response (< 90% necrosis). While tumor size and initial stage are also important, the histologic response to chemotherapy is a primary determinant of outcome.

Question 2510

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive distal thigh pain. Radiographs reveal a destructive, mixed lytic and sclerotic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. A core needle biopsy confirms a high-grade intramedullary osteosarcoma. Which of the following genetic alterations is most strongly associated with the pathogenesis of this tumor?

. t(11;22) translocation
. Mutation in the EXT1 gene
. Mutations in the RB1 and TP53 genes
. t(X;18) translocation
. Amplification of the MDM2 gene

Correct Answer & Explanation

. Mutations in the RB1 and TP53 genes

Explanation

High-grade intramedullary osteosarcoma is highly associated with mutations in tumor suppressor genes, particularly RB1 (Retinoblastoma) and TP53 (Li-Fraumeni syndrome). A t(11;22) translocation is associated with Ewing sarcoma. EXT1 is associated with multiple hereditary exostoses. A t(X;18) translocation is associated with synovial sarcoma. MDM2 amplification is characteristic of parosteal osteosarcoma and atypical lipomatous tumors.

Question 2511

Topic: 10. Pathology and Oncology

A 16-year-old male presents with persistent distal thigh pain. Imaging reveals a destructive, bone-forming lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms a high-grade intramedullary osteosarcoma. What is the standard sequence of treatment for this patient?

. Primary amputation followed by chemotherapy
. Neoadjuvant chemotherapy, followed by wide surgical resection, and then adjuvant chemotherapy
. Radiation therapy followed by wide surgical resection
. Wide surgical resection alone
. Neoadjuvant chemotherapy, followed by radiation therapy

Correct Answer & Explanation

. Neoadjuvant chemotherapy, followed by wide surgical resection, and then adjuvant chemotherapy

Explanation

The standard of care for classic high-grade osteosarcoma consists of neoadjuvant (preoperative) multiagent chemotherapy, followed by limb-sparing wide surgical resection (or amputation if limb salvage is impossible), and concluding with adjuvant (postoperative) chemotherapy. The histologic response to the neoadjuvant chemotherapy (percentage of tumor necrosis) is the single most important prognostic factor. Osteosarcoma is highly radioresistant.

Question 2512

Topic: 10. Pathology and Oncology
A 15-year-old boy is diagnosed with a conventional high-grade intramedullary osteosarcoma of the distal femur. He undergoes a standardized protocol of neoadjuvant chemotherapy followed by wide surgical resection. Which of the following factors determined from the surgical specimen is the most important prognostic indicator for long-term survival?
. Overall tumor volume
. Percentage of tumor necrosis
. Surgical margin width in millimeters
. Presence of skip metastasis on MRI
. Histologic subtype (e.g., osteoblastic vs. chondroblastic)

Correct Answer & Explanation

. Percentage of tumor necrosis

Explanation

The histologic response of the tumor to neoadjuvant chemotherapy, measured by the percentage of tumor necrosis, is one of the most powerful and reliable prognostic indicators for overall survival in osteosarcoma. A good response is defined as greater than 90% necrosis (Huvos grade III or IV) and correlates strongly with improved long-term survival.

Question 2513

Topic: 10. Pathology and Oncology
A 16-year-old male recently completed neoadjuvant chemotherapy for an osteosarcoma of the distal femur and subsequently undergoes wide local excision. Pathologic analysis of the resected specimen is performed. Which of the following factors is the most important independent prognostic indicator for overall survival in this patient?
. Tumor volume less than 200 cm³
. Anatomic location in the distal femur
. Chondroblastic histologic subtype
. Percentage of tumor necrosis post-chemotherapy > 90%
. Absence of skip lesions on preoperative MRI

Correct Answer & Explanation

. Percentage of tumor necrosis post-chemotherapy > 90%

Explanation

The histologic response of the primary tumor to neoadjuvant chemotherapy is one of the most powerful prognostic factors in osteosarcoma. A 'good response' is classically defined as greater than 90% tumor necrosis in the resected specimen. Patients who achieve this level of necrosis have a significantly improved disease-free and overall survival rate compared to 'poor responders' (<90% necrosis).

Question 2514

Topic: Soft Tissue Tumors & Metastasis

A 75-year-old woman notes a slowly enlarging mass in the right anterior thigh. Her medical history is significant only for hypertension. An MRI scan of her thigh is shown in Figures 60a through 60d. Which of the following surgical margins is the most appropriate for removal of this lesion?

. Radical
. Wide
. Marginal
. Intralesional
. Contaminated

Correct Answer & Explanation

. Marginal

Explanation

The patient has a large deep anterior thigh mass that has imaging characteristics of mature fat. Intramuscular lipomas are effectively treated with marginal resections with very low recurrence rates. Large lipomas often have small amounts of intralesional signal changes frequently representing trapped muscle fibers and do not necessitate more extensive margins. Gaskin CM, Helms CA: Lipomas, lipoma variants, and well-differentiated liposarcomas (atypical lipomas): Results of MRI evaluations of 126 consecutive fatty masses. Am J Roentgenol 2004;182:733-739.

Question 2515

Topic: 10. Pathology and Oncology

A 47-year-old woman has had a 1-month history of left hip and medial thigh pain that is exacerbated by sitting. Laboratory studies show a total protein level of 8.2 g/dL (normal 6.0 to 8.0) and an immunoglobulin G (IGG) level of 2,130 mg/dL (normal 562 to 1,835). A radiograph, CT scan, and biopsy specimen are shown in Figures 38a through 38c. What is the most likely diagnosis?

. Osteomyelitis
. Lymphoma
. Myeloma
. Ewing's sarcoma
. Osteosarcoma

Correct Answer & Explanation

. Myeloma

Explanation

The laboratory studies and histology are both consistent with myeloma. Infection should show white blood cells other than plasma cells on histology. Lymphoma would show lymphocytes, not plasma cells. The lack of bone formation on the imaging studies and the lack of osteoid on histology rule out osteosarcoma. The cells have too much cytoplasm and nuclear chromatin to be Ewing's sarcoma cells.

Question 2516

Topic: 10. Pathology and Oncology

An 18-year-old boy reports increasing pain with weight bearing on his right leg and at night. Examination reveals swelling around the right midcalf. Radiographs and an MRI scan are shown in Figures 13a through 13c, and a biopsy specimen is shown in Figure 13d. What is the preferred treatment?

. Chemotherapy and surgical resection
. Debridement and IV antibiotics
. Chemotherapy alone
. Radiation therapy alone
. Surgical resection alone

Correct Answer & Explanation

. Chemotherapy and surgical resection

Explanation

The findings are consistent with Ewing's sarcoma. The radiographs reveal a lytic lesion in the diaphysis of the right fibula. There is elevation of the periosteum and evidence of a surrounding soft-tissue mass. The biopsy specimen shows diffuse small round blue cells surrounding the lamellar bone. It is the second most common malignant bone tumor in children. The most common treatment regimen consists of chemotherapy followed by surgical resection and/or radiation therapy. Surgical resection is employed when the lesion can be removed with wide margins and causes less morbidity than radiation therapy. McCarthy EF, Frassica FJ: Pathology of Bone and Joint Disorders with Clinical and Radiographic Correlation. Philadelphia, PA, WB Saunders, 1998, p 258.

Question 2517

Topic: 10. Pathology and Oncology
A 63-year-old woman has a femoral neck fracture. A biopsy specimen obtained from the fracture site at the time of her hemiarthroplasty reveals metastatic carcinoma. Seven days after surgery, she becomes confused and lethargic. Which of the following laboratory values is most likely implicated in the patient's symptoms at this time?
. Hemoglobin level of 9.0 g/dL (normal value 11-15 g/dL)
. Sodium level of 132 mEq/L (normal value 135-145 mEq/L)
. Potassium level of 5.0 mEq/L (normal value 4.0-5.2 mEq/L)
. Calcium level of 15 mg/dL (normal value 8.5-10.5 mg/dL)
. Serum uric acid level of 10 mg/dL (normal value 2.7-7.3 mg/dL)

Correct Answer & Explanation

. Calcium level of 15 mg/dL (normal value 8.5-10.5 mg/dL)

Explanation

Although many hematologic and electrolyte abnormalities may be present in a patient with advanced metastatic cancer, an elevated serum calcium level is most commonly associated with confusion. Treatment with hydration, diuretics, and bisphosphonates is recommended. Clohishy D: Management of skeletal metastasis in clinical orthopaedics, in Craig E (ed): Operative Orthopaedics. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, pp 994-997.

Question 2518

Topic: 10. Pathology and Oncology

Figures 9a and 9b show the radiographs of a 12-year-old girl who has had right hip pain for the past 4 months. She reports that the pain is so severe that she is unable to walk and is now using a wheelchair. Examination reveals pain with any attempted range of motion. Management should include

. right innominate osteotomy.
. right varus upper femoral osteotomy.
. open reduction of the right hip.
. crutches, physical therapy, and an abduction brace.
. MRI of the pelvis.

Correct Answer & Explanation

. MRI of the pelvis.

Explanation

In addition to mild hip dysplasia, the radiograph shows an osteoblastic lesion of the right ilium. The patient's symptoms are much more severe than is typical for late hip dysplasia. MRI can determine the extent of the lesion in the bone and soft tissues. Following work-up and biopsy, the patient was diagnosed with Ewing's sarcoma. Springfield DS, Gebhardt MC: Bone and soft tissue tumors, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 507-518, 542-544.

Question 2519

Topic: 10. Pathology and Oncology

Figure 44 shows the radiograph of an 11-year-old girl who has hip pain. Further diagnostic workup should include

Orthopedic Surgery Board Review 2026 | High-Yield MCQs - Set 3 - Figure 43

. a renal ultrasound.
. an echocardiogram.
. an electromyogram.
. an MRI scan of the spine.
. an iliac crest biopsy.

Correct Answer & Explanation

. an echocardiogram.

Explanation

The patient has severe acetabular protrusio, a condition that is frequently associated with Marfan syndrome. An echocardiogram is necessary to rule out the most serious consequence of this syndrome, aortic root widening, which can lead to aortic valve dysfunction or fatal aortic rupture. An electromyogram may be indicated for Charcot-Marie-Tooth disease, which is associated with acetabular dysplasia, but not protrusio. The renal ultrasound, the MRI scan, and the biopsy would be of no value in this patient. Protrusio can also be seen in patients with osteogenesis imperfecta and juvenile rheumatoid arthritis. Steel HH: Protrusio acetabuli: Its occurrence in the completely expressed Marfan syndrome and its musculoskeletal component and a procedure to arrest the course of protrusion in the growing pelvis. J Pediatr Orthop 1996;16:704-718.

Question 2520

Topic: 10. Pathology and Oncology

A 75-year-old woman has had severe shoulder pain for the past month. Her medical history includes hypertension and a total nephrectomy for renal cell carcinoma 7 years ago. Radiographs and sagittal MRI scans are shown in Figures 36a through 36d. A bone scan reveals this to be an isolated lesion. Biopsy findings are consistent with metastatic renal cell carcinoma. What is the most appropriate treatment for this patient?

. Prophylactic stabilization with an intramedullary rod
. Radiation therapy alone
. Embolization alone
. Wide resection and prosthetic reconstruction
. Prophylactic stabilization with a locking plate and polymethylmethacrylate cement

Correct Answer & Explanation

. Wide resection and prosthetic reconstruction

Explanation

Resection and reconstruction of this very proximal lesion provides the best chance to avoid hardware complications that may be associated with stabilization procedures. Wide resection of isolated renal cell carcinoma metastasis, which presents distant to the nephrectomy, may improve long-term survival. Fuchs B, Trousdale RT, Rock MG: Solitary bony metastasis from renal cell carcinoma: Significance of surgical treatment. Clin Orthop Relat Res 2005;431:187-192.

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