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10. Pathology and Oncology MCQs

Practice Set 147 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 2921

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a painful mass in his distal femur. Biopsy confirms high-grade osteosarcoma. His family history is significant for a sister who developed breast cancer at age 30 and a mother who died of a soft-tissue sarcoma. Which of the following gene mutations is most likely responsible for this underlying familial syndrome?

. APC
. TP53
. EXT1
. NF1
. GNAS

Correct Answer & Explanation

. TP53

Explanation

This patient has a family history highly characteristic of Li-Fraumeni syndrome, which is caused by a germline mutation in the TP53 tumor suppressor gene. Patients with Li-Fraumeni syndrome have a significantly increased risk of developing osteosarcoma, soft-tissue sarcomas, breast cancer, leukemia, and brain tumors. APC is associated with familial adenomatous polyposis. EXT1 is associated with multiple hereditary exostoses. NF1 causes neurofibromatosis type 1. GNAS mutations are associated with McCune-Albright syndrome and fibrous dysplasia.

Question 2922

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a 2-month history of a painful diaphyseal mass in his right femur. Radiographs reveal a permeative destructive lesion with an aggressive 'onion-skin' periosteal reaction. Histologic examination demonstrates a uniform population of small round blue cells. Cytogenetic analysis of this tumor is most likely to reveal which of the following chromosomal translocations?

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

Correct Answer & Explanation

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

Explanation

The patient's presentation and histologic findings are diagnostic of Ewing sarcoma. Ewing sarcoma is classically associated with the t(11;22)(q24;q12) translocation, which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11. t(X;18) is associated with synovial sarcoma. t(12;16) is found in myxoid liposarcoma. t(2;13) is characteristic of alveolar rhabdomyosarcoma. t(9;22) is the Philadelphia chromosome seen in chronic myelogenous leukemia (CML).

Question 2923

Topic: 10. Pathology and Oncology

A 65-year-old man presents with severe back pain and fatigue. Radiographs of the spine and skull demonstrate multiple 'punched-out' lytic lesions without reactive sclerosis. Laboratory studies show hypercalcemia, anemia, and an elevated serum creatinine level. Serum protein electrophoresis reveals an M-spike. Radiographs of the right femur reveal a large 4 cm lytic lesion in the subtrochanteric region with 60% cortical destruction. What is the most appropriate initial management for the femur?

. Wide en bloc resection and endoprosthetic reconstruction
. Prophylactic intramedullary nailing followed by radiation and systemic therapy
. Curettage and bone grafting
. Observation and protected weight bearing until systemic therapy is initiated
. Neoadjuvant chemotherapy followed by curettage

Correct Answer & Explanation

. Prophylactic intramedullary nailing followed by radiation and systemic therapy

Explanation

The patient's presentation meets the CRAB criteria (hyperCalcemia, Renal failure, Anemia, Bone lesions) for multiple myeloma. The subtrochanteric femur lesion has a high risk of pathologic fracture (Mirels' criteria). The standard of care for an impending or actual pathologic fracture from multiple myeloma or metastatic disease in the diaphyseal/subtrochanteric femur is surgical stabilization, typically with an intramedullary nail, followed by local radiation therapy and systemic treatment for the myeloma. Wide en bloc resection is generally reserved for isolated solitary plasmacytomas or primary bone sarcomas.

Question 2924

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a slow-growing, painful mass on the plantar aspect of his foot. Magnetic resonance imaging demonstrates a soft-tissue mass adjacent to the plantar fascia. A biopsy reveals a biphasic pattern consisting of both spindle cells and epithelial cells. This specific tumor is most strongly associated with which of the following genetic abnormalities?

. t(12;16) FUS-DDIT3
. t(X;18) SYT-SSX
. t(11;22) EWS-FLI1
. MDM2 amplification
. APC mutation

Correct Answer & Explanation

. t(X;18) SYT-SSX

Explanation

The tumor described is a synovial sarcoma, which frequently presents in young adults as a deep-seated mass in the extremities, classically near joints or in the foot. Histologically, it can have a biphasic (spindle and epithelial components) or monophasic (spindle cells only) appearance. It is characterized by the t(X;18)(p11;q11) translocation, resulting in the fusion of the SYT gene on chromosome 18 with one of the SSX genes on the X chromosome.

Question 2925

Topic: 10. Pathology and Oncology
A 55-year-old man presents with a slowly expanding mass in his right pelvis. Radiographs show a lytic lesion with characteristic stippled and 'popcorn' calcifications in the ilium. Core needle biopsy confirms a grade II (intermediate-grade) conventional chondrosarcoma. Staging imaging shows no evidence of metastatic disease. Which of the following is the most appropriate definitive management?
. Neoadjuvant chemotherapy followed by wide surgical resection
. Wide surgical resection alone
. Radiation therapy followed by curettage
. Intralesional curettage and bone grafting
. Systemic targeted biologic therapy with a tyrosine kinase inhibitor

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas are notably resistant to both standard chemotherapy and radiation therapy due to their low mitotic fraction, poor vascularity, and abundant extracellular matrix. Therefore, the mainstay of treatment for intermediate (grade II) and high-grade (grade III) chondrosarcomas is wide surgical resection with negative margins. Intralesional curettage may be considered only for select benign or very low-grade (grade I/atypical cartilaginous tumor) lesions in the appendicular skeleton.

Question 2926

Topic: 10. Pathology and Oncology

A 16-year-old boy complains of nagging right thigh pain that is distinctly worse at night and dramatically relieved within 30 minutes of taking ibuprofen. Plain radiographs reveal a thickened diaphyseal cortex with a central 8-mm radiolucent nidus. The intense localized pain experienced by the patient is primarily mediated by local tumor production of which of the following substances?

. Interleukin-1
. Interleukin-6
. Prostaglandin E2
. Tumor necrosis factor-alpha
. Substance P

Correct Answer & Explanation

. Prostaglandin E2

Explanation

The clinical picture is pathognomonic for an osteoid osteoma. These benign bone-forming tumors secrete high levels of prostaglandins, specifically prostaglandin E2 (PGE2), which mediate the characteristic severe, nocturnal pain. The prompt relief of symptoms following the administration of nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin is due to the inhibition of cyclooxygenase, which decreases PGE2 production.

Question 2927

Topic: 10. Pathology and Oncology

A 45-year-old woman is evaluated for a deep, painless mass in her posterior thigh. MRI shows a large, well-circumscribed, multilobulated mass that is markedly hyperintense on T2-weighted images, resembling a cyst but with solid enhancement. Biopsy demonstrates a myxoid stroma with a rich, delicate, 'chicken-wire' capillary network and scattered lipoblasts. This tumor's pathogenesis is driven by a chromosomal translocation that leads to which of the following fusion genes?

. EWS-FLI1
. SYT-SSX
. FUS-DDIT3
. PAX3-FOXO1
. BCR-ABL

Correct Answer & Explanation

. FUS-DDIT3

Explanation

The clinical presentation, MRI findings (pseudocystic appearance on T2), and histology (myxoid stroma, chicken-wire vascularity, lipoblasts) are classic for myxoid liposarcoma. This soft-tissue sarcoma is characterized by the t(12;16)(q13;p11) translocation, which produces the FUS-DDIT3 (also known as TLS-CHOP) fusion transcript. EWS-FLI1 is seen in Ewing sarcoma; SYT-SSX in synovial sarcoma; PAX3-FOXO1 in alveolar rhabdomyosarcoma; and BCR-ABL in CML.

Question 2928

Topic: 10. Pathology and Oncology
According to the Musculoskeletal Tumor Society (MSTS) / Enneking staging system for malignant bone tumors, which of the following characteristics determines the difference between a Stage IIA and a Stage IIB lesion?
. Histologic grade of the tumor
. Presence of regional lymph node metastasis
. Presence of distant pulmonary metastasis
. Compartmental containment
. Tumor size greater than 8 cm

Correct Answer & Explanation

. Compartmental containment

Explanation

The MSTS/Enneking staging system for musculoskeletal sarcomas classifies tumors based on histologic grade (I = low grade, II = high grade), compartmental containment (A = intracompartmental, B = extracompartmental), and metastasis (III = any regional or distant metastasis). Therefore, a Stage II lesion is high grade. The distinction between Stage IIA and Stage IIB is strictly based on whether the tumor is confined within its anatomic compartment (IIA) or extends beyond the compartment boundaries (IIB).

Question 2929

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a painful, swollen thigh. Radiographs show a permeative diaphyseal lesion with an 'onion-skin' periosteal reaction. Biopsy reveals sheets of uniform small round blue cells. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical, radiographic, and histologic presentation is classic for Ewing sarcoma. The hallmark genetic abnormality is a balanced translocation between chromosomes 11 and 22, t(11;22)(q24;q12), which fuses the EWSR1 gene with the FLI1 gene. t(9;22) is seen in extraskeletal myxoid chondrosarcoma (and CML). t(X;18) is associated with synovial sarcoma. t(12;16) is seen in myxoid liposarcoma. t(2;13) is characteristic of alveolar rhabdomyosarcoma.

Question 2930

Topic: 10. Pathology and Oncology

A 45-year-old man with a history of multiple enchondromas (Ollier disease) presents with a rapidly enlarging, painful mass in his proximal humerus. Radiographs demonstrate a destructive bone lesion with intralesional 'ring and arc' calcifications and cortical breakthrough. A core needle biopsy confirms a high-grade conventional chondrosarcoma. Which of the following genetic mutations is most characteristic of the pathogenesis of this patient's underlying condition and subsequent malignant transformation?

. EXT1 and EXT2 mutations
. IDH1 and IDH2 mutations
. GNAS1 mutations
. t(11;22) chromosomal translocation
. p53 point mutation

Correct Answer & Explanation

. IDH1 and IDH2 mutations

Explanation

Mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2) are highly characteristic of solitary enchondromas, Ollier disease, Maffucci syndrome, and conventional chondrosarcomas. EXT1 and EXT2 mutations are associated with multiple hereditary exostoses (osteochondromas). GNAS1 mutations are seen in fibrous dysplasia (McCune-Albright syndrome). The t(11;22) translocation is characteristic of Ewing sarcoma.

Question 2931

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slowly enlarging, painless mass about the knee. Radiographs reveal a soft-tissue mass with stippled calcifications. MRI confirms a well-circumscribed soft-tissue lesion adjacent to the joint capsule but without intra-articular extension. A biopsy demonstrates a biphasic tumor containing both epithelioid and spindle cells. What is the characteristic chromosomal translocation diagnostic for this sarcoma?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The patient's clinical presentation, biphasic histology, and calcifications on radiograph (present in 30% of cases) are characteristic of Synovial Sarcoma. Synovial sarcoma is defined by the t(X;18) translocation, which creates the SYT-SSX fusion gene. t(11;22) is Ewing sarcoma; t(12;16) is myxoid liposarcoma; t(9;22) is extraskeletal myxoid chondrosarcoma; t(2;13) is alveolar rhabdomyosarcoma.

Question 2932

Topic: 10. Pathology and Oncology

A 55-year-old woman is scheduled for limb-salvage surgery for a 10 cm high-grade pleomorphic sarcoma of the anterior thigh. The multidisciplinary tumor board discusses the timing of radiation therapy (RT). If the patient receives preoperative (neoadjuvant) RT instead of postoperative RT, she is at highest risk for which of the following?

. Higher cumulative radiation dose toxicity
. Major acute wound healing complications
. Increased severe long-term limb edema
. Increased long-term joint stiffness and fibrosis
. Inferior overall survival at 5 years

Correct Answer & Explanation

. Major acute wound healing complications

Explanation

The seminal randomized trial by O'Sullivan et al. comparing preoperative versus postoperative radiation for extremity soft tissue sarcomas demonstrated that preoperative RT has a significantly higher risk of major acute wound complications (approx. 35% vs 17%). However, preoperative RT utilizes a lower total dose and a smaller radiation field, leading to significantly less long-term morbidity such as limb fibrosis, severe edema, and joint stiffness compared to postoperative RT. Overall survival rates are equivalent.

Question 2933

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a slow-growing mass in the plantar aspect of his foot. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components, establishing a diagnosis of synovial sarcoma. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is classically characterized by the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene. This translocation is found in over 90% of synovial sarcomas. t(11;22) is characteristic of Ewing sarcoma. t(12;16) is seen in myxoid liposarcoma. t(9;22) is associated with extraskeletal myxoid chondrosarcoma. t(2;13) is characteristic of alveolar rhabdomyosarcoma.

Question 2934

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain that is worse at night. Radiographs reveal a mixed lytic and sclerotic lesion with a sunburst periosteal reaction in the distal femur. A biopsy confirms osteosarcoma. Mutations in which of the following tumor suppressor genes are most frequently associated with the development of this malignancy?

. RB1 and TP53
. APC and PTEN
. BRCA1 and BRCA2
. NF1 and NF2
. EXT1 and EXT2

Correct Answer & Explanation

. RB1 and TP53

Explanation

Osteosarcoma is highly associated with mutations in the RB1 (retinoblastoma) and TP53 (Li-Fraumeni syndrome) tumor suppressor genes. Patients with hereditary retinoblastoma have a significantly increased risk of developing osteosarcoma. APC mutations are linked to familial adenomatous polyposis, NF1/NF2 to neurofibromatosis, and EXT1/EXT2 are associated with hereditary multiple exostoses (osteochondromas).

Question 2935

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a 2-month history of worsening thigh pain that frequently awakens him at night. Radiographs reveal a permeative, diaphyseal lesion in the femur with a lamellated 'onion-skin' periosteal reaction. A core needle biopsy is performed, demonstrating a uniform population of small blue cells. Which of the following chromosomal translocations is most strongly associated with this patient's diagnosis?

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

Correct Answer & Explanation

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

Explanation

The clinical and radiographic presentation, along with the biopsy finding of uniform small round blue cells, strongly supports the diagnosis of Ewing sarcoma. Ewing sarcoma is classically associated with the t(11;22)(q24;q12) translocation, which occurs in approximately 85% to 90% of cases and results in the EWS-FLI1 fusion protein. Synovial sarcoma is associated with t(X;18). The Philadelphia chromosome, t(9;22), is associated with chronic myelogenous leukemia (CML). Myxoid liposarcoma is characterized by t(12;16), and alveolar rhabdomyosarcoma is associated with t(2;13).

Question 2936

Topic: 10. Pathology and Oncology

In the staging and prognosis of adult soft-tissue sarcomas of the extremities, which of the following parameters is widely considered the single most important predictor of overall survival and the development of distant metastasis?

. Depth of the tumor relative to the fascia
. Tumor size (>5 cm vs <5 cm)
. Histologic grade
. Presence of regional lymph node metastasis
. Peritumoral edema on T2-weighted MRI

Correct Answer & Explanation

. Histologic grade

Explanation

While tumor size and depth are important staging variables (T-stage) that influence local recurrence and surgical planning, histologic grade is the single most important prognostic factor for overall survival and the risk of distant metastasis in adult soft-tissue sarcomas. Both the Musculoskeletal Tumor Society (MSTS/Enneking) and the American Joint Committee on Cancer (AJCC) staging systems heavily incorporate histologic grade (based on differentiation, mitotic count, and tumor necrosis) to dictate the stage grouping and systemic treatment algorithms.

Question 2937

Topic: 10. Pathology and Oncology

A 45-year-old man undergoes a biopsy of a painful, medullary lesion in his proximal humerus. Radiographs had shown endosteal scalloping and 'rings and arcs' calcifications. The biopsy confirms a Grade 2 conventional central chondrosarcoma. Somatic mutations in which of the following genes are most commonly implicated in the pathogenesis of this tumor and its benign precursor (enchondroma)?

. TP53
. EXT1
. GNAS
. IDH1 and IDH2
. RB1

Correct Answer & Explanation

. IDH1 and IDH2

Explanation

Mutations in the isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) genes are found in a large majority (>50-70%) of central enchondromas and conventional central chondrosarcomas. They are also the genetic hallmark of Ollier disease and Maffucci syndrome. EXT1 and EXT2 mutations are associated with multiple hereditary exostoses (osteochondromas). GNAS mutations are found in fibrous dysplasia. TP53 and RB1 are tumor suppressor genes whose mutations are classically associated with osteosarcoma.

Question 2938

Topic: 10. Pathology and Oncology

A 62-year-old woman with a history of metastatic breast cancer presents with severe right hip pain. The pain is functionally limiting and severely aggravated by weight-bearing. Radiographs show a purely lytic metastatic lesion in the peritrochanteric region of the right femur. The maximum diameter of the lesion occupies approximately 25% of the bone cortex. According to Mirels' criteria, what is her score, and what is the standard recommendation?

. Score 8; observation and bisphosphonate therapy
. Score 9; prophylactic internal fixation
. Score 10; prophylactic internal fixation
. Score 10; definitive radiation therapy without surgery
. Score 11; prophylactic internal fixation

Correct Answer & Explanation

. Score 10; prophylactic internal fixation

Explanation

Mirels' criteria are used to predict the risk of pathologic fracture and guide the decision for prophylactic fixation. The score is calculated based on four categories, each scoring 1 to 3 points. Site: upper extremity (1), lower extremity (2), peritrochanteric (3). Pain: mild (1), moderate (2), functional/mechanical (3). Lesion type: blastic (1), mixed (2), lytic (3). Size: <1/3 cortex (1), 1/3-2/3 cortex (2), >2/3 cortex (3). For this patient: Site = peritrochanteric (3); Pain = functional (3); Lesion = lytic (3); Size = 25% cortex (<1/3) (1). Total score = 3+3+3+1 = 10. A Mirels' score of 9 or greater carries a high risk of fracture, and prophylactic internal fixation is recommended.

Question 2939

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with progressive knee pain and a lytic diaphyseal lesion with a periosteal "onion-skin" reaction. A biopsy is performed, revealing sheets of small round blue cells. Cytogenetic analysis identifies a t(11;22) chromosomal translocation. This translocation results in the fusion of the EWS gene with which of the following genes?

. FLI1
. ERG
. CHOP
. SYT
. FOXO1

Correct Answer & Explanation

. FLI1

Explanation

Ewing sarcoma is a small round blue cell tumor. The most common chromosomal translocation is t(11;22)(q24;q12), which occurs in approximately 85-90% of cases and results in the fusion of the EWSR1 (EWS) gene on chromosome 22 with the FLI1 gene on chromosome 11. A less common translocation, t(21;22), involves the ERG gene. The CHOP gene is associated with myxoid liposarcoma, SYT with synovial sarcoma, and FOXO1 (FKHR) with alveolar rhabdomyosarcoma.

Question 2940

Topic: 10. Pathology and Oncology

A 65-year-old man with a history of renal cell carcinoma presents with right thigh pain. Radiographs reveal a large destructive lytic lesion in the proximal femur with an impending pathologic fracture. If prophylactic internal fixation is planned, which of the following perioperative measures is highly critical specific to this tumor type?

. Preoperative radiation therapy
. Preoperative embolization of the lesion
. Administration of systemic chemotherapy
. Wide en bloc resection instead of curettage
. Postoperative initiation of hyperbaric oxygen therapy

Correct Answer & Explanation

. Preoperative embolization of the lesion

Explanation

Renal cell carcinoma and thyroid carcinoma metastases to bone are classically extremely hypervascular. Surgical intervention, such as curettage or intramedullary nailing, can be associated with massive, life-threatening intraoperative hemorrhage. Preoperative selective arterial embolization (usually performed 24-48 hours before surgery) is a highly critical step to reduce tumor vascularity and minimize intraoperative blood loss.

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