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10. Pathology and Oncology MCQs

Practice Set 152 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 3021

Topic: 10. Pathology and Oncology

A 32-year-old male presents with a slowly growing, painful soft tissue mass near the knee joint. Biopsy demonstrates a biphasic tumor with both epithelial and spindle cell components. Molecular testing reveals a t(X;18) chromosomal translocation. This specific genetic alteration results in which oncogenic fusion protein?

. EWS-FLI1
. SYT-SSX
. FUS-CHOP
. PAX3-FOXO1
. MDM2 amplification

Correct Answer & Explanation

. SYT-SSX

Explanation

Synovial sarcoma is characterized by the pathognomonic t(X;18) translocation. This fuses the SYT gene on chromosome 18 with an SSX gene on the X chromosome, creating the SYT-SSX fusion protein that drives tumor proliferation.

Question 3022

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a painful, diaphyseal lesion of the femur. Biopsy reveals sheets of small, round, blue cells that strongly express CD99.

Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and histologic picture describes Ewing sarcoma. It is classically associated with the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein in approximately 85-90% of cases.

Question 3023

Topic: 10. Pathology and Oncology

A 60-year-old man presents with a painful, enlarging mass in his proximal humerus. Radiographs demonstrate a lytic lesion with intralesional "popcorn" calcifications and endosteal scalloping. Core biopsy confirms a Grade II conventional chondrosarcoma. What is the most appropriate management?

. Neoadjuvant chemotherapy followed by wide excision
. Wide surgical excision alone
. Intralesional curettage with phenol and polymethylmethacrylate
. Radiation therapy followed by wide excision
. High-dose methotrexate and local excision

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

Conventional intermediate- to high-grade chondrosarcomas are generally resistant to both chemotherapy and radiation. The mainstay of potentially curative treatment is wide surgical excision to obtain negative margins.

Question 3024

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a slow-growing, painful mass adjacent to his knee joint. Histology reveals a biphasic pattern consisting of spindle cells and epithelial cells.

Which cytogenetic abnormality is pathognomonic for this tumor?

. t(X;18) (p11;q11)
. t(12;16) (q13;p11)
. t(9;22) (q22;q12)
. t(2;13) (q35;q14)
. t(11;22) (q24;q12)

Correct Answer & Explanation

. t(X;18) (p11;q11)

Explanation

The mass is a synovial sarcoma, characterized histologically by biphasic or monophasic cellular patterns. It is cytogenetically defined by the t(X;18) chromosomal translocation, which results in the SYT-SSX fusion gene.

Question 3025

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a diaphyseal lesion of the femur and an 'onion-skin' periosteal reaction. Biopsy reveals sheets of small round blue cells.

Which chromosomal translocation is most characteristically associated with this diagnosis?

. t(11;22)(q24;q12)
. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(9;22)(q22;q12)
. t(2;13)(q35;q14)

Correct Answer & Explanation

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

Explanation

Ewing sarcoma is characterized by the t(11;22) translocation, which results in the EWS-FLI1 fusion protein in approximately 85% of cases. t(X;18) is associated with synovial sarcoma, and t(12;16) is associated with myxoid liposarcoma.

Question 3026

Topic: 10. Pathology and Oncology

An 18-year-old male presents with dull back pain that is worse at night and relieved by NSAIDs. Radiographs show a distinct lesion in the posterior elements of L4. Which of the following features most reliably differentiates osteoblastoma from osteoid osteoma?

. Presence of woven bone on histology
. Complete pain relief in response to prostaglandins
. Lesion size greater than 2 cm
. High potential for malignant transformation
. Presence of a thick sclerotic margin

Correct Answer & Explanation

. Lesion size greater than 2 cm

Explanation

Osteoblastoma and osteoid osteoma are histologically identical benign bone-forming tumors. They are primarily distinguished by size, with osteoblastomas being larger than 2 cm and often demonstrating more progressive, aggressive local growth.

Question 3027

Topic: 10. Pathology and Oncology

A 50-year-old male undergoes a biopsy of a 6 cm deep soft tissue mass in his thigh, which confirms high-grade pleomorphic sarcoma. Staging workup shows no metastases. According to the AJCC staging system, what is the most important prognostic factor for determining the stage of this localized tumor?

. Tumor depth relative to the investing fascia
. Tumor size
. Histologic grade
. Patient age
. Presence of necrosis

Correct Answer & Explanation

. Histologic grade

Explanation

Histologic grade is the single most important prognostic factor for soft tissue sarcomas. In the AJCC staging system for non-metastatic soft tissue sarcomas, histologic grade is a primary determinant of the overall stage.

Question 3028

Topic: 10. Pathology and Oncology

A 55-year-old woman with breast cancer presents with a destructive lesion in her proximal femur. According to Mirels' criteria, which of the following findings contributes the maximum points (3 points) toward indicating the need for prophylactic internal fixation?

. Upper extremity location
. Blastic nature of the lesion
. Size of the lesion being less than 1/3 of the cortex
. Severe pain
. Mild pain

Correct Answer & Explanation

. Severe pain

Explanation

Mirels' scoring system evaluates the risk of pathologic fracture based on site, pain, lesion type, and size. Severe pain, peritrochanteric location, lytic nature, and a lesion size greater than 2/3 of the cortex each score the maximum of 3 points.

Question 3029

Topic: 10. Pathology and Oncology
A 14-year-old boy is diagnosed with high-grade conventional osteosarcoma of the proximal tibia. Following neoadjuvant chemotherapy, what percentage of tumor necrosis on the resection specimen is considered the threshold for a good histologic response?
. 50%
. 75%
. 85%
. 90%
. 99%

Correct Answer & Explanation

. 90%

Explanation

According to the Huvos grading system, a good histologic response to neoadjuvant chemotherapy in osteosarcoma is defined as 90% or greater tumor necrosis (Grade III or IV response). This correlates with significantly improved disease-free survival.

Question 3030

Topic: 10. Pathology and Oncology

A 12-year-old girl presents with thigh pain and a permeative diaphyseal lesion with a periosteal "onion-skin" reaction on radiographs. Biopsy reveals small round blue cells. 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(11;22)

Explanation

The clinical scenario is classic for Ewing sarcoma. Over 85% of Ewing sarcomas are characterized by the t(11;22) chromosomal translocation, resulting in the EWS-FLI1 fusion protein.

Question 3031

Topic: 10. Pathology and Oncology
According to the Enneking surgical staging system for malignant musculoskeletal tumors, a high-grade intra-compartmental lesion without regional or distant metastasis is classified as:
. Stage IA
. Stage IB
. Stage IIA
. Stage IIB
. Stage III

Correct Answer & Explanation

. Stage IIB

Explanation

In the Enneking staging system, Stage II designates a high-grade tumor. The suffix 'A' denotes an intra-compartmental location, while 'B' indicates an extra-compartmental location.

Question 3032

Topic: 10. Pathology and Oncology

A 25-year-old man presents with a slow-growing, painful soft tissue mass in the plantar aspect of his foot. Biopsy identifies a biphasic tumor with both epithelial and spindle cell components. Which genetic abnormality is diagnostic for this tumor?

. t(X;18) SYT-SSX
. t(11;22) EWS-FLI1
. t(2;13) PAX3-FOXO1
. t(12;16) FUS-DDIT3
. MDM2 amplification

Correct Answer & Explanation

. t(X;18) SYT-SSX

Explanation

Synovial sarcoma classically presents in young adults and can occur in the foot or ankle. It is genetically defined by the t(X;18) chromosomal translocation, resulting in the SYT-SSX fusion gene.

Question 3033

Topic: Bone Tumors

A 16-year-old boy presents with knee pain. Radiographs reveal an expansile, eccentric lytic lesion in the proximal tibial metaphysis. MRI demonstrates multiple fluid-fluid levels. Genetic analysis of this lesion would most likely reveal an abnormality involving which of the following genes?

. USP6
. GNAS
. EXT1
. RB1
. TP53

Correct Answer & Explanation

. USP6

Explanation

The imaging findings are classic for an aneurysmal bone cyst (ABC). Primary ABCs are true neoplasms driven by recurrent translocations involving the USP6 gene on chromosome 17p13.

Question 3034

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a slowly enlarging, painless mass around his knee joint. An incisional biopsy is performed, and cytogenetic analysis reveals a t(X;18)(p11;q11) chromosomal translocation. Which of the following is the most likely diagnosis?

. Ewing sarcoma
. Synovial sarcoma
. Alveolar rhabdomyosarcoma
. Clear cell sarcoma
. Myxoid liposarcoma

Correct Answer & Explanation

. Synovial sarcoma

Explanation

Synovial sarcoma is uniquely characterized by the t(X;18)(p11;q11) translocation, resulting in the SYT-SSX fusion gene. It often presents in young adults as a slow-growing mass near large joints.

Question 3035

Topic: 10. Pathology and Oncology

A 16-year-old boy presents with severe right thigh pain that is significantly worse at night and dramatically relieved by ibuprofen. Radiographs show a distinct radiolucent nidus surrounded by intense reactive sclerosis in the femoral diaphysis. The profound pain response to nonsteroidal anti-inflammatory drugs in this condition is primarily due to high levels of which of the following locally produced substances?

. Interleukin-1
. Tumor necrosis factor-alpha
. Prostaglandin E2
. Bone morphogenetic protein-2
. Vascular endothelial growth factor

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteoma lesions produce high levels of Prostaglandin E2 (PGE2), which causes the characteristic night pain. This is why nonsteroidal anti-inflammatory drugs (NSAIDs) typically provide dramatic relief.

Question 3036

Topic: 10. Pathology and Oncology

A 65-year-old man with a history of renal cell carcinoma presents with thigh pain. Radiographs reveal a large, purely lytic lesion in the proximal femur with a high risk of impending fracture. If surgical stabilization is planned, which of the following is the most appropriate preoperative intervention?

. Radiation therapy
. Neoadjuvant chemotherapy
. Preoperative angiogram and embolization
. Bisphosphonate infusion
. Bone marrow aspiration

Correct Answer & Explanation

. Preoperative angiogram and embolization

Explanation

Metastatic renal cell carcinoma is highly vascular and carries a severe risk of massive intraoperative hemorrhage. Preoperative selective embolization of the feeding vessels is strongly recommended before orthopedic stabilization.

Question 3037

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with localized pain and swelling in the diaphyseal region of the fibula. Imaging shows a permeative, destructive lesion with an "onion-skin" periosteal reaction. Biopsy reveals small blue cells. Which of the following gene fusions is most commonly associated with this tumor?

. EWS-FLI1
. SYT-SSX1
. PAX3-FOXO1
. TLS-CHOP
. COL1A1-PDGFB

Correct Answer & Explanation

. EWS-FLI1

Explanation

This presentation is classic for Ewing sarcoma, which frequently exhibits a permeative diaphyseal lesion with onion-skin periostitis. The most common genetic abnormality is a t(11;22) translocation yielding the EWS-FLI1 fusion protein.

Question 3038

Topic: 10. Pathology and Oncology

Which of the following metastatic bone lesions most consistently exhibits an osteoblastic (sclerotic) appearance on plain radiographs?

. Lung carcinoma
. Renal cell carcinoma
. Thyroid carcinoma
. Prostate carcinoma
. Multiple myeloma

Correct Answer & Explanation

. Prostate carcinoma

Explanation

Metastatic prostate cancer classically produces osteoblastic (sclerotic) lesions in bone. In contrast, renal, thyroid, lung, and multiple myeloma typically produce purely lytic lesions.

Question 3039

Topic: 10. Pathology and Oncology

A 55-year-old woman is evaluated for a localized mass in the proximal humerus. Radiographs show a poorly marginated lesion with "ring and arc" calcifications. Biopsy confirms an intermediate-grade chondrosarcoma. What is the standard of care for managing this lesion?

. Wide surgical excision alone
. Neoadjuvant chemotherapy followed by wide excision
. Radiation therapy alone
. Curettage and bone grafting
. Intralesional steroid injection

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

Conventional chondrosarcomas are generally resistant to both chemotherapy and radiation. The definitive treatment for intermediate or high-grade conventional chondrosarcoma is wide surgical excision.

Question 3040

Topic: 10. Pathology and Oncology

A 60-year-old man presents with diffuse bone pain, fatigue, and recurrent infections. A skeletal survey reveals multiple "punched-out" lytic bone lesions, but his technetium-99m bone scan is largely unremarkable. What is the most likely diagnosis?

. Metastatic prostate cancer
. Paget disease of bone
. Multiple myeloma
. Osteosarcoma
. Chondrosarcoma

Correct Answer & Explanation

. Multiple myeloma

Explanation

Multiple myeloma characteristically produces lytic "punched-out" bone lesions without stimulating an osteoblastic response. Because technetium-99m bone scans detect osteoblastic activity, they are typically cold (unremarkable) in myeloma.

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