Menu

10. Pathology and Oncology MCQs

Practice Set 151 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 3001

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a permeative lytic lesion in the diaphysis of the femur with an associated "onion skin" periosteal reaction. Biopsy confirms Ewing sarcoma. Which of the following fusion proteins is most commonly associated with this tumor?

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

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is most commonly associated with the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein. This acts as an aberrant transcription factor driving oncogenesis.

Question 3002

Topic: 10. Pathology and Oncology

A 30-year-old woman presents with knee pain. Radiographs show an eccentric, lytic, epiphyseal lesion in the distal femur extending to the subchondral bone. Biopsy reveals multinucleated giant cells interspersed with mononuclear stromal cells. Which of the following cells expresses RANKL in this tumor?

. Multinucleated giant cells
. Mononuclear stromal cells
. Osteocytes
. Chondrocytes
. Macrophages

Correct Answer & Explanation

. Mononuclear stromal cells

Explanation

In a Giant Cell Tumor of bone, the neoplastic mononuclear stromal cells express RANKL. This recruits and activates the reactive multinucleated giant cells that cause the characteristic osteolytic bone destruction.

Question 3003

Topic: 10. Pathology and Oncology

Which of the following is the most significant prognostic factor for survival in a patient with localized high-grade osteosarcoma following neoadjuvant chemotherapy?

. Age at diagnosis
. Size of the primary tumor
. Histologic response to neoadjuvant chemotherapy
. Anatomic location of the tumor
. Gender of the patient

Correct Answer & Explanation

. Histologic response to neoadjuvant chemotherapy

Explanation

The percentage of tumor necrosis (histologic response) following neoadjuvant chemotherapy is the most critical prognostic indicator for overall survival in high-grade osteosarcoma. Greater than 90% necrosis is considered a good response.

Question 3004

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in the diaphysis of his femur. Biopsy reveals uniform small round blue cells. Cytogenetic analysis of this tumor is most likely to show which of the following translocations?

. 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 a small round blue cell tumor typically arising in the diaphysis of long bones. It is genetically characterized by the t(11;22) translocation, which results in the EWS-FLI1 fusion protein.

Question 3005

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a slow-growing, deep-seated soft tissue mass near the knee joint. Biopsy shows a biphasic pattern of spindle and epithelial cells. Which molecular abnormality is diagnostic for this lesion?

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

Correct Answer & Explanation

. t(X;18) (SYT-SSX)

Explanation

Synovial sarcoma classically presents as a deep soft tissue mass near a joint in a young adult. The pathognomonic molecular marker is the t(X;18) translocation, creating the SYT-SSX fusion gene.

Question 3006

Topic: Bone Tumors

A 10-year-old girl is evaluated for a Shepherd's crook deformity of the proximal femur. Radiographs show a ground-glass appearance of the medullary canal. This condition is associated with a postzygotic somatic mutation in which of the following genes?

. EXT1
. GNAS
. RB1
. PTEN
. NF1

Correct Answer & Explanation

. GNAS

Explanation

Fibrous dysplasia is a developmental anomaly of bone caused by a somatic activating mutation in the GNAS gene. This leads to increased intracellular cAMP and impaired differentiation of bone-forming cells.

Question 3007

Topic: Bone Tumors

A 12-year-old girl has an expansile, eccentric lytic lesion in the proximal tibia. MRI reveals multiple fluid-fluid levels. Primary aneurysmal bone cysts are genetically characterized by a rearrangement involving which of the following genes?

. USP6
. GNAS
. EXT1
. FLI1
. TP53

Correct Answer & Explanation

. USP6

Explanation

Primary aneurysmal bone cysts are considered true neoplasms driven by rearrangements of the USP6 gene on chromosome 17. This distinguishes them from secondary aneurysmal bone cysts, which lack this genetic mutation.

Question 3008

Topic: 10. Pathology and Oncology

A 19-year-old man complains of severe right thigh pain that is worse at night and dramatically relieved by ibuprofen. Radiographs show dense cortical thickening with a small radiolucent nidus. The intense pain associated with this lesion is mediated by high local concentrations of which substance?

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

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteomas produce exceptionally high levels of Prostaglandin E2 (PGE2) due to high expression of COX-2 within the tumor nidus. NSAIDs effectively relieve the pain by blocking this specific pathway.

Question 3009

Topic: 10. Pathology and Oncology

A 55-year-old man presents with a painful mass in the proximal humerus. Radiographs show a large lytic lesion with intralesional "popcorn" calcifications and endosteal scalloping. Which of the following is the most critical factor in determining the surgical management and prognosis of this primary bone tumor?

. Tumor size
. Histologic grade
. Patient age
. Presence of t(12;16)
. Serum alkaline phosphatase levels

Correct Answer & Explanation

. Histologic grade

Explanation

For conventional chondrosarcoma, histologic grade is the most important prognostic factor and dictates surgical management. High-grade tumors require wide resection, while selected low-grade tumors may be treated with extended intralesional curettage.

Question 3010

Topic: 10. Pathology and Oncology

A 20-year-old man with multiple hereditary exostoses (MHE) notes rapid growth and increasing pain in a previously asymptomatic mass on his distal femur. What is the most reliable MRI finding suggesting malignant transformation to secondary chondrosarcoma?

. Cartilage cap thickness greater than 2 cm
. Bone marrow edema in the stalk
. Periosteal reaction at the base
. Multiple septations within the stalk
. Joint effusion

Correct Answer & Explanation

. Cartilage cap thickness greater than 2 cm

Explanation

In skeletally mature adults with osteochondromas, a cartilage cap thickness greater than 1.5 to 2 cm on MRI is highly suspicious for malignant transformation to a secondary peripheral chondrosarcoma.

Question 3011

Topic: 10. Pathology and Oncology

A 35-year-old man presents with a deep, slow-growing soft tissue mass near his knee joint. Biopsy reveals a biphasic tumor with spindle and epithelial cells. Which of the following chromosomal translocations is most likely 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(X;18)(p11;q11)

Explanation

Synovial sarcoma is characterized by the t(X;18) translocation, which results in the SYT-SSX fusion gene. This molecular marker is critical for confirming the diagnosis of synovial sarcoma.

Question 3012

Topic: 10. Pathology and Oncology

A 65-year-old man presents with back pain and hypercalcemia. Radiographs demonstrate "punched-out" lytic lesions in the skull and vertebral bodies. Which cytokine is primarily responsible for the aggressive osteoclastic bone resorption seen in this malignant condition?

. Interleukin-1 (IL-1)
. Interleukin-6 (IL-6)
. Tumor necrosis factor-alpha (TNF-a)
. Transforming growth factor-beta (TGF-b)
. Macrophage colony-stimulating factor (M-CSF)

Correct Answer & Explanation

. Interleukin-6 (IL-6)

Explanation

The clinical picture describes multiple myeloma. Myeloma cells and supporting bone marrow stromal cells secrete high levels of IL-6 (and RANKL), which heavily stimulates osteoclastogenesis and leads to characteristic lytic bone lesions.

Question 3013

Topic: 10. Pathology and Oncology

What is widely considered the most significant prognostic factor for overall disease-free survival in a pediatric patient with localized high-grade intramedullary osteosarcoma following neoadjuvant chemotherapy?

. Absolute tumor volume at initial clinical presentation
. Age and sex of the patient
. Anatomic location of the primary bone tumor
. Histologic response (percentage of tumor necrosis) in the resected specimen
. Type of planned surgical reconstructive procedure

Correct Answer & Explanation

. Histologic response (percentage of tumor necrosis) in the resected specimen

Explanation

The histologic response to neoadjuvant chemotherapy is the most powerful prognostic indicator in high-grade osteosarcoma. A good response is typically defined as greater than 90% tumor necrosis in the definitive surgical specimen.

Question 3014

Topic: 10. Pathology and Oncology

A 30-year-old woman presents with knee pain. Radiographs reveal an eccentric, lytic lesion in the distal femur extending to the subchondral bone. Biopsy shows multinucleated giant cells in a background of mononuclear stromal cells. Which specific cell type in this tumor harbors the neoplastic genetic alteration (e.g., H3F3A mutation)?

. The multinucleated giant cells
. The mononuclear spindle-shaped stromal cells
. The reactive marrow macrophages
. The osteoblasts at the lesional periphery
. The infiltrating cytotoxic T-lymphocytes

Correct Answer & Explanation

. The mononuclear spindle-shaped stromal cells

Explanation

In Giant Cell Tumor of bone, the true neoplastic cells are the mononuclear spindle-shaped stromal cells, which harbor the signature H3F3A mutation. The abundant multinucleated giant cells are merely reactive, osteoclast-like cells recruited by the stroma.

Question 3015

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a permeative lytic lesion in the diaphysis of his femur.

Biopsy demonstrates small round blue cells. Cytogenetic analysis is most likely to reveal which of the following translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and histologic description is classic for Ewing sarcoma. The most common cytogenetic abnormality in Ewing sarcoma is the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein.

Question 3016

Topic: 10. Pathology and Oncology

A 40-year-old man presents with a painless, slow-growing mass in his thigh.

MRI reveals a well-circumscribed lesion that is hyperintense on T1-weighted images and loses signal on fat-suppressed sequences. What is the most likely diagnosis?

. Liposarcoma
. Myxoma
. Hemangioma
. Lipoma
. Schwannoma

Correct Answer & Explanation

. Lipoma

Explanation

Lipomas are benign tumors of mature adipose tissue that exhibit high signal intensity on T1-weighted MRI (matching subcutaneous fat) and demonstrate signal drop-out on fat-suppression sequences.

Question 3017

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with severe thigh pain and a low-grade fever. Radiographs show a permeative diaphyseal lesion in the femur with an "onion skin" periosteal reaction. Biopsy reveals sheets of uniform, small, round, blue cells. Which chromosomal translocation is most definitively associated with this patient's diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma classically presents with a permeative diaphyseal lesion and is genetically characterized by the t(11;22) translocation. This results in the EWS-FLI1 fusion protein, which acts as an aberrant transcription factor.

Question 3018

Topic: Bone Tumors

A 22-year-old male presents with severe nocturnal anterior thigh pain that is reliably relieved by oral ibuprofen. Radiographs demonstrate a 1-cm radiolucent nidus surrounded by thick cortical sclerosis in the proximal femoral diaphysis. What is the most appropriate definitive management for this lesion?

. Wide en bloc resection
. Neoadjuvant chemotherapy followed by resection
. Radiofrequency ablation
. Intralesional curettage and polymethylmethacrylate cementation
. Indefinite observation

Correct Answer & Explanation

. Radiofrequency ablation

Explanation

The clinical history and radiographic appearance are classic for an osteoid osteoma. Percutaneous radiofrequency ablation (RFA) is currently the standard of care, offering a minimally invasive, definitive cure with low morbidity.

Question 3019

Topic: 10. Pathology and Oncology

A 55-year-old male incidentally presents with an expansile, radiolucent lesion featuring central "rings and arcs" calcifications in the proximal humerus. Biopsy confirms a grade 1 (low-grade) conventional central chondrosarcoma. Which of the following is the standard recommended surgical treatment for this appendicular lesion?

. Preoperative radiation therapy followed by wide resection
. Extended intralesional curettage, burring, and local adjuvant therapy
. Wide en bloc resection with 2-cm margins
. Amputation
. Systemic chemotherapy

Correct Answer & Explanation

. Extended intralesional curettage, burring, and local adjuvant therapy

Explanation

Low-grade (Grade 1) central chondrosarcomas in the appendicular skeleton can often be safely managed with joint-sparing extended intralesional curettage, high-speed burring, and chemical adjuvants (like phenol or cryotherapy). High-grade or pelvic lesions require wide en bloc resection.

Question 3020

Topic: Bone Tumors

A 10-year-old girl is evaluated for a leg length discrepancy and a "shepherd's crook" deformity of her proximal femur. Radiographs reveal an intramedullary lesion with a hazy, "ground-glass" matrix. This disorder is driven by a somatic postzygotic mutation in which of the following genes?

. EXT1
. GNAS
. FGFR3
. COL1A1
. RUNX2

Correct Answer & Explanation

. GNAS

Explanation

Fibrous dysplasia is caused by an activating missense mutation in the GNAS gene, which encodes the alpha subunit of the stimulatory G protein (Gs-alpha). This leads to increased intracellular cAMP and abnormal osteoblast differentiation.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page