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10. Pathology and Oncology MCQs

Practice Set 173 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 3441

Topic: 10. Pathology and Oncology

A 65-year-old man notes a rapidly growing mass in his proximal thigh. MRI shows a large, heterogeneous, deep intramuscular mass.

Core needle biopsy shows highly pleomorphic spindle cells with abundant atypical mitoses and no distinct line of differentiation. What is the most appropriate next step in local management for this presumed Undifferentiated Pleomorphic Sarcoma (UPS)?

. Marginal excision
. Preoperative radiation followed by wide local excision
. Amputation through the hip joint
. Chemotherapy only
. Observation until it becomes symptomatic

Correct Answer & Explanation

. Preoperative radiation followed by wide local excision

Explanation

Undifferentiated Pleomorphic Sarcoma (formerly MFH) is the most common soft tissue sarcoma in older adults. The standard of care for high-grade, deep soft-tissue sarcomas >5cm is wide local excision combined with radiation therapy.

Question 3442

Topic: 10. Pathology and Oncology



A 45-year-old male presents with progressive right knee pain, locking, and mechanical symptoms. Radiographs show multiple intra-articular calcified loose bodies of relatively uniform size. What is the underlying pathophysiology of this specific primary condition?

. Metaplasia of the synovial membrane
. Fragmentation of osteophytes
. Chondral shedding from repetitive microtrauma
. Autoimmune destruction of articular cartilage
. Malignant transformation of resident chondrocytes

Correct Answer & Explanation

. Metaplasia of the synovial membrane

Explanation

Primary synovial chondromatosis is a benign nodular proliferation resulting from metaplasia of the synovial membrane. The loose bodies are typically uniform in size, which helps differentiate it from secondary forms resulting from osteoarthritis or trauma.

Question 3443

Topic: 10. Pathology and Oncology

A 55-year-old female presents with a painless, rapidly growing 8 cm mass in her anterior thigh. MRI demonstrates a deep, heterogenous soft tissue mass. Core biopsy confirms a high-grade pleomorphic sarcoma. According to the AJCC staging system for soft tissue sarcomas, what is the most critical prognostic factor for overall survival?

. Tumor depth relative to the fascia
. Absolute tumor size in centimeters
. Histologic grade of the tumor
. Patient age at diagnosis
. Presence of microscopic nodal involvement

Correct Answer & Explanation

. Histologic grade of the tumor

Explanation

Histologic grade is the most important prognostic factor for distant metastasis and overall survival in soft tissue sarcomas. While size and depth are important for clinical staging, grade determines the biological aggressiveness of the tumor.

Question 3444

Topic: 10. Pathology and Oncology



A 30-year-old male presents with a deep-seated, slow-growing mass near the popliteal fossa. Histology demonstrates a biphasic pattern consisting of spindle cells and epithelial cells. Which specific chromosomal translocation is pathognomonic for this tumor?

. 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(X;18)(p11;q11)

Explanation

Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene. Despite its name, this sarcoma rarely arises directly from an intra-articular synovial membrane.

Question 3445

Topic: 10. Pathology and Oncology

You are planning a biopsy for a suspected soft tissue sarcoma located in the anterior compartment of the thigh. Which of the following is an essential surgical principle to avoid compromising the future definitive limb-salvage resection?

. Use a transverse skin incision to parallel Langer's lines
. Proceed through intermuscular planes to minimize intramuscular bleeding
. Ensure the biopsy tract is placed in line with the planned definitive longitudinal resection incision
. Perform an excisional biopsy for tumors up to 8 cm to obtain adequate tissue
. Obtain the biopsy specifically from the necrotic center of the tumor

Correct Answer & Explanation

. Ensure the biopsy tract is placed in line with the planned definitive longitudinal resection incision

Explanation

Longitudinal incisions in the extremities allow the biopsy tract to be excised en bloc safely during definitive limb-salvage surgery. Transverse incisions and dissection through intermuscular planes contaminate additional compartments, complicating the definitive resection.

Question 3446

Topic: 10. Pathology and Oncology



A 45-year-old patient presents with a large, deep thigh mass. Histopathology reveals a plexiform capillary network with lipoblasts and a prominent myxoid stroma. Cytogenetics show t(12;16). Which of the following statements is uniquely true regarding the management of this specific sarcoma?

. It is highly resistant to radiation therapy requiring immediate radical resection
. It has a high propensity to metastasize exclusively to the lungs
. It is highly radiosensitive compared to other adult soft tissue sarcomas
. Amputation is the gold standard due to rapid local recurrence
. It requires routine prophylactic inguinal lymph node dissection

Correct Answer & Explanation

. It is highly radiosensitive compared to other adult soft tissue sarcomas

Explanation

Myxoid liposarcoma is characterized by the t(12;16) FUS-DDIT3 translocation and is known for being exquisitely sensitive to radiotherapy. Uniquely, it has a high propensity to metastasize to extrapulmonary sites such as the spine and other soft tissues.

Question 3447

Topic: 10. Pathology and Oncology

A 25-year-old female presents with a slow-growing mass in her right thigh. MRI reveals a highly vascular mass. She reports recent onset of severe headaches, and an MRI of the brain demonstrates a solitary metastatic lesion. What is the most likely diagnosis?

. Epithelioid sarcoma
. Clear cell sarcoma
. Alveolar soft part sarcoma
. Rhabdomyosarcoma
. Synovial sarcoma

Correct Answer & Explanation

. Alveolar soft part sarcoma

Explanation

Alveolar soft part sarcoma is a rare, highly vascular tumor typically affecting young adults. It is notorious for frequently metastasizing to the lungs and brain, with brain metastases being a hallmark feature in advanced disease.

Question 3448

Topic: 10. Pathology and Oncology



A patient is undergoing neoadjuvant radiation therapy for a large high-grade soft tissue sarcoma of the distal thigh, which will be followed by wide surgical resection. Compared to adjuvant (postoperative) radiation, what is the primary clinical disadvantage of the neoadjuvant approach?

. Higher total radiation dose is required
. Increased risk of major acute wound complications
. Greater long-term joint stiffness and limb fibrosis
. Decreased likelihood of achieving negative surgical margins
. Increased lifetime risk of radiation-induced secondary sarcoma

Correct Answer & Explanation

. Increased risk of major acute wound complications

Explanation

Neoadjuvant (preoperative) radiation therapy significantly increases the risk of acute wound healing complications compared to postoperative radiation. However, postoperative radiation requires a higher total dose and a larger field, leading to worse long-term fibrosis and edema.

Question 3449

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a painless mass in the deep soft tissues of his foot, intimately associated with the plantar aponeurosis. Histology shows nested cells separated by fibrous septa that stain positive for HMB-45 and S-100. Cytogenetics reveal t(12;22)(q13;q12). What is the diagnosis?

. Malignant melanoma
. Synovial sarcoma
. Clear cell sarcoma
. Epithelioid sarcoma
. Fibrosarcoma

Correct Answer & Explanation

. Clear cell sarcoma

Explanation

Clear cell sarcoma (historically called melanoma of soft parts) is characterized by the t(12;22) translocation and positive melanin markers (HMB-45, S-100). It typically arises in the deep soft tissues and aponeuroses of the distal extremities in young adults.

Question 3450

Topic: 10. Pathology and Oncology

A 45-year-old male presents with a painless, deep thigh mass measuring 8 cm. Core needle biopsy confirms a high-grade soft tissue sarcoma.

What is the most critical prognostic factor for his overall survival?

. Tumor depth
. Tumor size
. Histologic grade
. Surgical margin width
. Presence of necrosis

Correct Answer & Explanation

. Histologic grade

Explanation

Histologic grade is the most important prognostic factor for overall survival and distant metastasis in soft tissue sarcomas. While size and depth are also prognostic, grade dictates the underlying biological aggressiveness of the tumor.

Question 3451

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a progressive, firm mass in her right foot. Biopsy reveals a spindle cell neoplasm. Molecular testing shows a t(12;22) translocation resulting in an EWS-ATF1 fusion. What is the most likely diagnosis?

. Synovial sarcoma
. Clear cell sarcoma
. Alveolar soft part sarcoma
. Epithelioid sarcoma
. Myxoid liposarcoma

Correct Answer & Explanation

. Clear cell sarcoma

Explanation

Clear cell sarcoma (melanoma of soft parts) is characterized by the t(12;22) translocation and typically presents in the foot or ankle of young adults. It shares immunohistochemical markers with melanoma, such as S-100 and HMB-45 positivity.

Question 3452

Topic: 10. Pathology and Oncology

A 20-year-old male is diagnosed with a soft tissue sarcoma of the distal thigh. The pathology report demonstrates a biphasic tumor with both epithelial and spindle cell components. Which chromosomal translocation is highly specific for this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma classically exhibits the t(X;18)(p11;q11) translocation, which creates the SYT-SSX fusion gene. It often presents in young adults near large joints but rarely involves the actual joint synovium directly.

Question 3453

Topic: 10. Pathology and Oncology

A 22-year-old male with a history of recurrent wrist nodules presents with an ulcerating mass on the volar aspect of his hand. Lymph node biopsy is positive for metastasis. Which of the following soft tissue sarcomas has the highest propensity for lymphatic spread?

. Myxoid liposarcoma
. Pleomorphic liposarcoma
. Epithelioid sarcoma
. Fibrosarcoma
. Undifferentiated pleomorphic sarcoma

Correct Answer & Explanation

. Epithelioid sarcoma

Explanation

Epithelioid sarcoma frequently presents as an ulcerating hand or forearm mass in young adults and has a uniquely high rate of lymph node metastasis (up to 30%). Sentinel lymph node biopsy or regional node evaluation is often recommended.

Question 3454

Topic: 10. Pathology and Oncology

A 60-year-old male presents with a large, deep intramuscular mass in the posterior thigh. Biopsy shows an undifferentiated pleomorphic sarcoma. The multidisciplinary team recommends pre-operative radiation therapy. Which of the following is a known disadvantage of pre-operative radiation compared to post-operative radiation?

. Higher total radiation dose is required
. Larger treatment field is needed
. Higher rate of major wound complications
. Higher risk of late joint contracture
. Higher risk of permanent nerve damage

Correct Answer & Explanation

. Higher rate of major wound complications

Explanation

Pre-operative radiation for soft tissue sarcomas is associated with a significantly higher rate of major surgical wound complications compared to post-operative radiation. However, it requires a lower total dose, a smaller field, and results in fewer long-term fibrosis and joint stiffness issues.

Question 3455

Topic: Soft Tissue Tumors & Metastasis

A 45-year-old female presents with a painless 10 cm soft tissue mass in her retroperitoneum, discovered incidentally. Biopsy reveals atypical lipoblasts with an amplified MDM2 gene. What is the most likely diagnosis?

. Myxoid liposarcoma
. Pleomorphic liposarcoma
. Well-differentiated liposarcoma
. Spindle cell lipoma
. Angiolipoma

Correct Answer & Explanation

. Well-differentiated liposarcoma

Explanation

Well-differentiated and dedifferentiated liposarcomas are uniquely characterized by the amplification of the MDM2 and CDK4 genes on chromosome 12q. They commonly occur in the retroperitoneum and deep tissues of the extremities.

Question 3456

Topic: 10. Pathology and Oncology

A 30-year-old woman is diagnosed with Alveolar Soft Part Sarcoma (ASPS) of the thigh. Due to the specific clinical behavior of this tumor, which additional staging study is strictly indicated?

. Bone marrow biopsy
. Brain MRI
. Mesenteric angiography
. Sentinel lymph node biopsy
. Whole body skeletal survey

Correct Answer & Explanation

. Brain MRI

Explanation

Alveolar soft part sarcoma (ASPS) has a distinct propensity to metastasize early to the brain (up to 30% of cases). Therefore, a staging MRI of the brain is strongly indicated upon initial diagnosis.

Question 3457

Topic: 10. Pathology and Oncology

Which soft tissue sarcoma is notoriously characterized by a "myxoid" background with a rich, delicate "chicken-wire" capillary network, and responds exceptionally well to pre-operative radiation therapy?

. Epithelioid sarcoma
. Myxoid liposarcoma
. Synovial sarcoma
. Undifferentiated pleomorphic sarcoma
. Fibrosarcoma

Correct Answer & Explanation

. Myxoid liposarcoma

Explanation

Myxoid liposarcoma classically shows a 'chicken-wire' capillary network and a t(12;16) translocation. It is uniquely radiosensitive, often demonstrating dramatic shrinkage and extensive necrosis following pre-operative radiotherapy.

Question 3458

Topic: 10. Pathology and Oncology

A 50-year-old male is undergoing surgical excision of a large, high-grade soft tissue sarcoma of the anterior thigh.

According to standard oncologic principles, what defines an adequate surgical margin in this setting?

. 2 cm of normal tissue in all directions
. Microscopically negative margins regardless of width
. 1 cm margin of muscle or fascia
. Removal of the entire muscle compartment
. A margin free of tumor cells at the inked surface on histology

Correct Answer & Explanation

. A margin free of tumor cells at the inked surface on histology

Explanation

Current oncologic principles for soft tissue sarcoma emphasize achieving a microscopically negative margin (R0 resection), defined as no tumor cells at the inked margin. The absolute metric width is less critical than the biological quality of the barrier, especially near resistant fascia.

Question 3459

Topic: 10. Pathology and Oncology
A patient with multiple café-au-lait spots, precocious puberty, and polyostotic fibrous dysplasia presents with a progressively painful bowing deformity of the femur. Which genetic mechanism is responsible for this syndrome?
. Inactivating mutation of the NF1 gene
. Activating mutation of the GNAS1 gene
. Mutation in the EXT1 gene
. Mutation in the COL1A1 gene
. Amplification of MDM2

Correct Answer & Explanation

. Activating mutation of the GNAS1 gene

Explanation

McCune-Albright syndrome is caused by a somatic, activating mutation of the GNAS1 gene, leading to the overproduction of cAMP. It manifests with polyostotic fibrous dysplasia, endocrinopathies, and café-au-lait spots with irregular borders.

Question 3460

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a slowly enlarging, firm, multi-nodular mass over the anterior aspect of the distal thigh. A biopsy shows a high-grade soft tissue sarcoma.

What is the most common route of metastasis for this group of tumors?

. Lymphatic spread to regional nodes
. Hematogenous spread to the liver
. Hematogenous spread to the lungs
. Direct extension into the bone
. Perineural invasion

Correct Answer & Explanation

. Hematogenous spread to the lungs

Explanation

The lung is the most common site of metastasis for the vast majority of soft tissue sarcomas, occurring via hematogenous spread. A baseline chest CT is mandatory for oncologic staging.

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