Menu

10. Pathology and Oncology MCQs

Practice Set 249 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 4961

Topic: 10. Pathology and Oncology

A patient with Ewing's Sarcoma presents with a pathological fracture of the femur. What is the appropriate initial management strategy?

. Immediate surgical stabilization and definitive resection
. Radiation therapy to the fracture site followed by chemotherapy
. Initiation of neoadjuvant chemotherapy, with fracture stabilization if symptomatic or unstable
. Amputation as the primary treatment due to poor prognosis
. Observation with close monitoring, avoiding surgical intervention

Correct Answer & Explanation

. Initiation of neoadjuvant chemotherapy, with fracture stabilization if symptomatic or unstable

Explanation

For a pathological fracture in Ewing's Sarcoma, the initial management prioritizes systemic disease control. Neoadjuvant chemotherapy should be initiated promptly to treat potential micrometastases and achieve tumor regression. Fracture stabilization (e.g., intramedullary nailing) is performed if the fracture causes significant pain or instability, or if it delays chemotherapy. Definitive surgical resection is typically planned after chemotherapy. Immediate definitive resection is often not ideal due to the risk of tumor dissemination and the need for systemic therapy first. Amputation is a last resort, and observation is inappropriate for an aggressive tumor with a pathological fracture.

Question 4962

Topic: 10. Pathology and Oncology

Which of the following is a recognized late complication of radiation therapy used in the treatment of Ewing's Sarcoma, particularly in pediatric patients?

. Cardiotoxicity
. Nephrotoxicity
. Secondary malignancies
. Peripheral neuropathy
. Hemorrhagic cystitis

Correct Answer & Explanation

. Secondary malignancies

Explanation

Secondary malignancies (e.g., osteosarcoma, thyroid cancer, leukemia) are a significant late complication of radiation therapy, especially in growing children, due to radiation-induced DNA damage. Other late effects include growth plate arrest leading to limb length discrepancy, scoliosis (for spinal irradiation), joint stiffness, and soft tissue fibrosis. Cardiotoxicity (e.g., from doxorubicin), nephrotoxicity (e.g., from ifosfamide), peripheral neuropathy (e.g., from vincristine), and hemorrhagic cystitis (e.g., from cyclophosphamide/ifosfamide) are typically associated with chemotherapy, not radiation directly.

Question 4963

Topic: 10. Pathology and Oncology

A 14-year-old girl is found to have Ewing's Sarcoma of the sacrum. Given the location, what is a primary concern regarding surgical resection?

. Risk of pulmonary metastasis
. Preservation of adjacent growth plates
. Difficulty in achieving wide surgical margins and potential neurological deficits
. Increased likelihood of developing osteonecrosis
. Early development of pathologic fracture

Correct Answer & Explanation

. Difficulty in achieving wide surgical margins and potential neurological deficits

Explanation

Sacral Ewing's Sarcoma presents significant challenges for surgical resection. The complex anatomy, proximity to critical neurovascular structures (sacral nerve roots, rectum, bladder), and the difficulty in achieving wide tumor-free margins without causing severe functional impairment (e.g., bladder/bowel incontinence, motor/sensory deficits) are primary concerns. Pulmonary metastasis is a systemic staging issue, not a direct surgical concern for local control. Preservation of growth plates is more relevant for extremity tumors in younger patients. Osteonecrosis is a potential complication of radiation or steroid use, not specific to sacral surgery. Pathologic fracture risk exists but is not the primary surgical concern forresectionchallenges.

Question 4964

Topic: 10. Pathology and Oncology

What is the typical age range for the highest incidence of Ewing's Sarcoma?

. Infancy (0-2 years)
. Preschool children (3-5 years)
. Adolescents and young adults (10-20 years)
. Middle-aged adults (40-60 years)
. Elderly individuals (>70 years)

Correct Answer & Explanation

. Adolescents and young adults (10-20 years)

Explanation

Ewing's Sarcoma is predominantly a tumor of childhood and adolescence, with the highest incidence occurring in individuals between 10 and 20 years of age. It is rare in infants and older adults, though cases outside this typical range do occur.

Question 4965

Topic: 10. Pathology and Oncology

A core biopsy confirms Ewing's Sarcoma. Which additional diagnostic procedure is essential for initial staging to detect metastatic disease?

. Electromyography (EMG) of the affected limb
. Arteriogram of the tumor site
. Bone marrow aspiration and biopsy
. Myelogram if the tumor is spinal
. Doppler ultrasound of regional lymph nodes

Correct Answer & Explanation

. Bone marrow aspiration and biopsy

Explanation

Ewing's Sarcoma has a high propensity for micrometastasis, and common sites include the lungs, bone, and bone marrow. Therefore, a bone marrow aspiration and biopsy is a crucial component of the initial staging workup to detect bone marrow involvement, which affects prognosis and treatment decisions. CT chest, bone scan, and/or PET-CT are also essential for evaluating other metastatic sites. The other options are not standard for initial systemic staging.

Question 4966

Topic: 10. Pathology and Oncology

Regarding the differential diagnosis of Ewing's Sarcoma, which tumor shares the 'small round blue cell' histological appearance and must be differentiated?

. Osteosarcoma
. Chondrosarcoma
. Fibrosarcoma
. Rhabdomyosarcoma
. Giant Cell Tumor of Bone

Correct Answer & Explanation

. Rhabdomyosarcoma

Explanation

Ewing's Sarcoma is classically described as a 'small round blue cell tumor.' Other tumors that fall into this category and must be differentiated include Rhabdomyosarcoma, Lymphoma, Neuroblastoma, and occasionally Primitive Neuroectodermal Tumor (PNET), which is now considered part of the Ewing's sarcoma family of tumors. Osteosarcoma and chondrosarcoma are typically spindle cell or cartilaginous tumors, respectively. Fibrosarcoma is a spindle cell tumor, and Giant Cell Tumor is characterized by multinucleated giant cells and mononuclear stromal cells.

Question 4967

Topic: 10. Pathology and Oncology

Which of the following chemotherapy agents is NOT typically part of the standard multi-agent regimen for Ewing's Sarcoma?

. Vincristine
. Doxorubicin
. Cyclophosphamide
. Methotrexate (high dose)
. Ifosfamide

Correct Answer & Explanation

. Methotrexate (high dose)

Explanation

The standard chemotherapy regimen for Ewing's Sarcoma commonly includes Vincristine, Doxorubicin, Cyclophosphamide, Ifosfamide, and Etoposide (often abbreviated as VDC/IE). High-dose methotrexate is a key agent in osteosarcoma chemotherapy but is not a standard component of Ewing's Sarcoma regimens. While other agents might be used in specific circumstances or relapse, the core drugs are as listed.

Question 4968

Topic: 10. Pathology and Oncology

What is the typical effect of effective neoadjuvant chemotherapy on a Ewing's Sarcoma tumor?

. Increased tumor vascularity and rapid growth
. Softening of the tumor, reduction in size, and consolidation of the periosteal reaction
. Increased tumor cellularity and mitotic activity
. Conversion of a lytic lesion to a purely blastic lesion on X-ray
. Development of new skip lesions distant from the primary tumor

Correct Answer & Explanation

. Softening of the tumor, reduction in size, and consolidation of the periosteal reaction

Explanation

Effective neoadjuvant chemotherapy aims to reduce tumor size (debulking), improve resectability, decrease tumor burden, and treat micrometastases. Radiographically, this often translates to a reduction in the soft tissue component, consolidation or remodeling of the periosteal reaction, and a decrease in the lytic activity, sometimes with increased sclerosis. Histologically, it leads to tumor necrosis. Increased vascularity or growth, increased cellularity, or new skip lesions would indicate treatment failure or progression.

Question 4969

Topic: 10. Pathology and Oncology

Which gene fusion is considered diagnostic for Ewing's sarcoma family of tumors?

. BCR-ABL
. MYC-IG
. EWSR1-FLI1
. ALK rearrangement
. RET rearrangement

Correct Answer & Explanation

. EWSR1-FLI1

Explanation

The EWSR1-FLI1 fusion (most commonly t(11;22)) is the defining genetic hallmark of Ewing's Sarcoma and related tumors (Ewing Sarcoma family of tumors, ESFT). While there are other EWSR1 gene partners (e.g., ERG, FEV, ETV1), EWSR1-FLI1 is the most prevalent. BCR-ABL is associated with CML, MYC-IG with Burkitt lymphoma, ALK rearrangement with anaplastic large cell lymphoma and non-small cell lung cancer, and RET rearrangement with papillary thyroid cancer and other neoplasms.

Question 4970

Topic: 10. Pathology and Oncology

During the evaluation of a suspected Ewing's Sarcoma, what is the role of a CT scan of the chest?

. To assess local tumor extent and bone involvement in the primary site
. To detect pulmonary metastases, which are common at diagnosis
. To evaluate neurological deficits related to spinal involvement
. To identify skip lesions in the affected extremity
. To quantify tumor necrosis after chemotherapy

Correct Answer & Explanation

. To detect pulmonary metastases, which are common at diagnosis

Explanation

CT scan of the chest is an essential part of the initial staging for Ewing's Sarcoma to detect pulmonary metastases. The lungs are the most common site of metastasis at diagnosis, accounting for approximately 25-30% of cases. MRI is preferred for local tumor extent, CT or MRI for spinal involvement, and MRI for skip lesions. Quantification of tumor necrosis is typically done histologically after resection.

Question 4971

Topic: 10. Pathology and Oncology

The presence of a 'small round blue cell tumor' on biopsy requires differentiation from several entities. Besides immunohistochemistry, what specialized test confirms Ewing's Sarcoma?

. Electron microscopy for Birbeck granules
. Fluorescence In Situ Hybridization (FISH) for EWSR1 gene rearrangement
. Enzyme-linked immunosorbent assay (ELISA) for tumor markers
. Flow cytometry for surface markers
. Immunophenotyping for T-cell receptors

Correct Answer & Explanation

. Fluorescence In Situ Hybridization (FISH) for EWSR1 gene rearrangement

Explanation

Given the characteristic genetic translocations, Fluorescence In Situ Hybridization (FISH) for the EWSR1 gene rearrangement (e.g., EWSR1-FLI1) is a highly specific and definitive test for confirming the diagnosis of Ewing's Sarcoma. Electron microscopy for Birbeck granules is for Langerhans cell histiocytosis. ELISA is for circulating markers. Flow cytometry and immunophenotyping are primarily used for hematolymphoid malignancies.

Question 4972

Topic: 10. Pathology and Oncology

What is the primary role of high-dose chemotherapy with autologous stem cell rescue in the management of Ewing's Sarcoma?

. Routine frontline treatment for all localized Ewing's Sarcomas
. Standard treatment for low-risk localized disease
. Salvage therapy for recurrent or high-risk metastatic disease
. Prevention of chemotherapy-induced neuropathy
. Primary treatment for isolated pulmonary metastases

Correct Answer & Explanation

. Salvage therapy for recurrent or high-risk metastatic disease

Explanation

High-dose chemotherapy with autologous stem cell rescue is typically reserved for patients with recurrent Ewing's Sarcoma or those with high-risk metastatic disease at diagnosis, particularly if they have a good response to conventional chemotherapy. It is not a routine frontline treatment for all localized disease due to significant toxicity. It is a salvage strategy to intensify treatment beyond what can be delivered without stem cell support.

Question 4973

Topic: 10. Pathology and Oncology

Which statement regarding the role of surgical margins in Ewing's Sarcoma is correct?

. Marginal resections are acceptable due to the efficacy of adjuvant chemotherapy.
. Intralesional resections are curative if followed by radiation therapy.
. Wide surgical margins (R0 resection) are associated with the best local control and overall survival.
. Positive surgical margins (R1 resection) are always treated with amputation.
. Biopsy-only is sufficient if chemotherapy achieves complete response.

Correct Answer & Explanation

. Wide surgical margins (R0 resection) are associated with the best local control and overall survival.

Explanation

Achieving wide surgical margins, leading to an R0 resection (no microscopic tumor at the margin), is a critical prognostic factor for local control and overall survival in Ewing's Sarcoma. While chemotherapy and radiation are vital components of multimodal therapy, negative surgical margins significantly reduce the risk of local recurrence. Marginal or intralesional resections without clear margins carry a higher risk of recurrence and usually necessitate adjuvant radiation. Positive margins do not automatically lead to amputation but require further local treatment, often radiation, and sometimes re-excision.

Question 4974

Topic: 10. Pathology and Oncology

A patient with Ewing's Sarcoma of the femur develops severe myelosuppression during chemotherapy. Which of the following is the most appropriate management strategy?

. Immediate cessation of all chemotherapy
. Increase the dosage of the current chemotherapy agents
. Administration of granulocyte colony-stimulating factors (G-CSFs) and potential dose reductions or delays
. Switch to a completely different chemotherapy regimen immediately
. Surgical removal of bone marrow

Correct Answer & Explanation

. Administration of granulocyte colony-stimulating factors (G-CSFs) and potential dose reductions or delays

Explanation

Myelosuppression (bone marrow suppression) is a common and dose-limiting toxicity of chemotherapy, particularly with agents used in Ewing's Sarcoma. Management typically involves supportive care, including the administration of granulocyte colony-stimulating factors (G-CSFs) to promote white blood cell recovery, and if severe, temporary dose reductions or delays in chemotherapy cycles to allow for marrow recovery. Complete cessation of chemotherapy or increasing dosages would be inappropriate. Switching regimens is usually reserved for non-response or specific toxicities, not routine myelosuppression. Surgical removal of bone marrow is irrelevant.

Question 4975

Topic: 10. Pathology and Oncology

What is the significance of serum LDH (Lactate Dehydrogenase) levels in Ewing's Sarcoma?

. It is a specific diagnostic marker for Ewing's Sarcoma.
. Elevated levels correlate with a better prognosis and response to treatment.
. It is a non-specific marker, but elevated levels often indicate a higher tumor burden and poorer prognosis.
. LDH levels are only elevated in the presence of liver metastases.
. It is used to monitor the effectiveness of local radiation therapy.

Correct Answer & Explanation

. It is a non-specific marker, but elevated levels often indicate a higher tumor burden and poorer prognosis.

Explanation

Serum LDH is a non-specific tumor marker that can be elevated in various cancers, including Ewing's Sarcoma. While not diagnostic, elevated LDH levels at diagnosis in Ewing's Sarcoma are generally considered a poor prognostic indicator, often correlating with higher tumor burden, more aggressive disease, and a worse outcome. It is not specific to liver metastases, nor does it typically monitor local radiation effectiveness.

Question 4976

Topic: 10. Pathology and Oncology

Extraskeletal Ewing's Sarcoma most commonly arises in which location?

. Brain parenchyma
. Spinal cord
. Kidney
. Soft tissues of the trunk and extremities
. Thyroid gland

Correct Answer & Explanation

. Soft tissues of the trunk and extremities

Explanation

Extraskeletal Ewing's Sarcoma is a rare variant that arises in soft tissues without primary bone involvement. The most common sites are the soft tissues of the trunk and extremities, including paravertebral regions, chest wall, retroperitoneum, and deep soft tissues of the limbs. Brain, spinal cord, kidney, and thyroid are rare or atypical primary sites for extraskeletal Ewing's.

Question 4977

Topic: 10. Pathology and Oncology

What is the recommended surveillance schedule for patients after completion of Ewing's Sarcoma treatment?

. Annual follow-up with plain radiographs only for 5 years.
. Clinical exam, chest imaging (CT or X-ray), and blood tests every 3-4 months for the first 2-3 years, then less frequently.
. Monthly MRI scans of the primary site for 1 year.
. No further follow-up is needed after 2 years if no recurrence.
. Bone scan every 6 months indefinitely.

Correct Answer & Explanation

. Clinical exam, chest imaging (CT or X-ray), and blood tests every 3-4 months for the first 2-3 years, then less frequently.

Explanation

Post-treatment surveillance for Ewing's Sarcoma is crucial for detecting recurrence or secondary malignancies. A typical schedule involves frequent clinical exams, chest imaging (CT or X-ray for pulmonary mets), and blood tests (including LDH) every 3-4 months for the first 2-3 years, when the risk of recurrence is highest. The frequency then decreases to every 6 months for another 2-3 years, and then annually for several more years. MRI of the primary site is usually done less frequently than monthly. No follow-up after 2 years is insufficient. Bone scans are used if new bone symptoms arise, not routinely every 6 months indefinitely.

Question 4978

Topic: 10. Pathology and Oncology

Which finding on a follow-up PET-CT scan after completion of Ewing's Sarcoma treatment would be most concerning for recurrence?

. Stable mild FDG uptake in a known benign cyst
. Diffuse low-grade FDG uptake in the liver
. New focal area of intense FDG avidity in the vertebral body distant from the primary site
. Physiologic FDG uptake in the brain
. Decreased FDG uptake in an area of post-radiation fibrosis

Correct Answer & Explanation

. New focal area of intense FDG avidity in the vertebral body distant from the primary site

Explanation

PET-CT detects metabolically active tissue. A new focal area of intense FDG avidity in a vertebral body (or any new site) would be highly suspicious for a new bone metastasis, indicating disease recurrence, especially if distant from the primary site. Stable mild uptake in a benign lesion, diffuse low-grade uptake, physiologic uptake, or decreased uptake in fibrosis are typically benign or expected post-treatment findings.

Question 4979

Topic: 10. Pathology and Oncology

When considering radiation therapy for Ewing's Sarcoma, what is the primary indication for its use in conjunction with surgery?

. As a substitute for systemic chemotherapy
. To prevent limb length discrepancy in children
. To sterilize positive or close surgical margins and treat unresectable disease
. To increase bone density in the treated area
. To induce a pathologic fracture for easier resection

Correct Answer & Explanation

. To sterilize positive or close surgical margins and treat unresectable disease

Explanation

Radiation therapy is a critical component of multimodal treatment for Ewing's Sarcoma. Its primary indications are to improve local control in cases where surgical margins are positive or close (R1 or R2 resection), or when the tumor is unresectable. It is never a substitute for systemic chemotherapy, which addresses micrometastases. It does not prevent limb length discrepancy (it can cause it), nor does it increase bone density or induce fractures for easier resection.

Question 4980

Topic: Bone Tumors

Which characteristic typically distinguishes Ewing's Sarcoma from osteosarcoma on a plain radiograph?

. Ewing's often presents with an 'onion-skin' periosteal reaction, while osteosarcoma commonly shows a 'sunburst' or Codman's triangle.
. Ewing's is usually a purely sclerotic lesion, while osteosarcoma is purely lytic.
. Ewing's primarily affects the epiphysis, whereas osteosarcoma affects the diaphysis.
. Ewing's lesions typically have sharp, well-defined margins, unlike osteosarcoma.
. Osteosarcoma rarely has a soft tissue mass, while Ewing's always does.

Correct Answer & Explanation

. Ewing's often presents with an 'onion-skin' periosteal reaction, while osteosarcoma commonly shows a 'sunburst' or Codman's triangle.

Explanation

Ewing's Sarcoma classically presents with a lamellated ('onion-skin') periosteal reaction due to its rapid, infiltrative growth pattern. Osteosarcoma, in contrast, frequently demonstrates a 'sunburst' periosteal reaction (spicules perpendicular to the cortex) or a Codman's triangle (triangular elevation of the periosteum). Ewing's is typically lytic, and osteosarcoma can be lytic, sclerotic, or mixed. Ewing's usually affects diaphysis/metadiaphysis, while osteosarcoma typically affects the metaphysis. Both often have poorly defined margins and a significant soft tissue mass.

Test Yourself

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

On this Page