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10. Pathology and Oncology MCQs

Practice Set 326 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 6501

Topic: 10. Pathology and Oncology

A 45-year-old male presents with a large, deep thigh mass. Biopsy reveals a myxoid background, a plexiform "chicken-wire" capillary network, and lipoblasts. Which genetic translocation is characteristically present in this malignancy?

. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)
. t(11;22)(q24;q12)
. t(17;22)(q22;q13)

Correct Answer & Explanation

. t(12;16)(q13;p11)

Explanation

Myxoid liposarcoma is characterized by the t(12;16)(q13;p11) translocation, resulting in the FUS-DDIT3 fusion. Unlike other soft tissue sarcomas, it has a unique propensity to metastasize to extrapulmonary sites like the spine and other soft tissues.

Question 6502

Topic: 10. Pathology and Oncology

A 60-year-old male is scheduled for a wide resection of an undifferentiated pleomorphic sarcoma in his proximal thigh.

In randomized trials comparing preoperative versus postoperative radiation therapy for soft tissue sarcomas, postoperative radiation is associated with a significantly higher risk of which complication?

. Major acute wound healing complications
. Local tumor recurrence
. Long-term joint stiffness and tissue fibrosis
. Distant pulmonary metastasis
. Pathologic fracture

Correct Answer & Explanation

. Long-term joint stiffness and tissue fibrosis

Explanation

Postoperative radiation requires a higher total dose and larger treatment volume compared to preoperative radiation. This leads to significantly higher rates of long-term morbidities such as tissue fibrosis, joint stiffness, and chronic edema.

Question 6503

Topic: 10. Pathology and Oncology

A 17-year-old female presents with a biopsy-proven chondroblastoma of the proximal tibial epiphysis. She is treated with intralesional curettage and bone grafting. Which of the following is true regarding the systemic behavior of this tumor?

. It has no metastatic potential under any circumstances.
. Pulmonary metastases can occur despite benign histology and are treated with surgical resection.
. Local recurrence is rare and indicates malignant transformation.
. Malignant transformation to chondrosarcoma occurs in 20% of cases.
. Adjuvant chemotherapy is routinely indicated to prevent lymphatic spread.

Correct Answer & Explanation

. Pulmonary metastases can occur despite benign histology and are treated with surgical resection.

Explanation

Although chondroblastoma is a benign tumor, it can rarely produce "benign" pulmonary metastases (1-2% of cases). These lung lesions typically have limited growth potential and are treated successfully with wedge resection.

Question 6504

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a large, progressive desmoid tumor of the shoulder girdle.

He reports a strong family history of colon cancer and osteomas. He is most likely to harbor a germline mutation in which gene?

. APC
. TP53
. RB1
. NF1
. CTNNB1

Correct Answer & Explanation

. CTNNB1

Explanation

Desmoid tumors are strongly associated with Familial Adenomatous Polyposis (Gardner syndrome), caused by germline mutations in the APC gene. Sporadic desmoid tumors, however, are usually driven by somatic mutations in the CTNNB1 (beta-catenin) gene.

Question 6505

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a deep mass intimately associated with the Achilles tendon. Biopsy reveals nests of pale, spindle-shaped cells that stain strongly positive for HMB-45 and S-100. The tumor exhibits a t(12;22) translocation. What is the diagnosis?

. Synovial sarcoma
. Epithelioid sarcoma
. Clear cell sarcoma
. Alveolar soft part sarcoma
. Undifferentiated pleomorphic sarcoma

Correct Answer & Explanation

. Clear cell sarcoma

Explanation

Clear cell sarcoma (historically called melanoma of soft parts) typically arises near tendons or aponeuroses in young adults. It is positive for melanocytic markers (S-100, HMB-45) and is characterized by the EWSR1-ATF1 t(12;22) fusion.

Question 6506

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a firm, slow-growing, ulcerating nodule on his right index finger, initially misdiagnosed as a wart. Biopsy reveals a nodular proliferation of epithelioid cells with central necrosis. Which statement regarding the metastatic behavior of this specific sarcoma is correct?

. It spreads exclusively via direct local extension.
. It has an unusually high propensity for regional lymph node metastasis.
. Lymphatic spread only occurs secondary to overwhelming pulmonary burden.
. It selectively metastasizes to the axial skeleton.
. Sentinel lymph node biopsy provides no prognostic value.

Correct Answer & Explanation

. It has an unusually high propensity for regional lymph node metastasis.

Explanation

Epithelioid sarcoma commonly presents as a superficial ulcerating nodule on the distal extremities of young adults. Uniquely among soft tissue sarcomas, it has a very high rate of regional lymph node metastasis, necessitating nodal evaluation.

Question 6507

Topic: 10. Pathology and Oncology

A 33-year-old female presents with an unresectable, highly symptomatic extra-abdominal desmoid tumor involving the neurovascular bundle of her lower extremity.

Which systemic targeted therapy has been recently FDA-approved specifically for progressive, unresectable desmoid tumors?

. Imatinib
. Sorafenib
. Nirogacestat
. Denosumab
. Pembrolizumab

Correct Answer & Explanation

. Nirogacestat

Explanation

Nirogacestat, an oral gamma-secretase inhibitor, is the first FDA-approved systemic therapy for progressing desmoid tumors. It acts by preventing the cleavage of Notch, disrupting the pathway crosstalk that drives these tumors.

Question 6508

Topic: 10. Pathology and Oncology
According to the AJCC staging system for soft tissue sarcomas of the extremities, which of the following is the most critical prognostic factor for predicting the risk of distant metastasis and determining the overall stage?
. Tumor depth relative to the investing fascia
. Maximum tumor diameter
. Histologic grade
. Patient age at diagnosis
. Proximity to a major neurovascular bundle

Correct Answer & Explanation

. Histologic grade

Explanation

Histologic grade (typically assessed by the FNCLCC grading system) is the single most important prognostic factor for soft tissue sarcomas. It heavily dictates the risk of distant metastasis and overall survival.

Question 6509

Topic: 10. Pathology and Oncology

A 5-year-old boy presents with a rapidly enlarging, deep mass in his forearm. Biopsy confirms alveolar rhabdomyosarcoma. What cytogenetic abnormality is most frequently associated with this diagnosis?

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

Correct Answer & Explanation

. t(2;13)(q35;q14)

Explanation

Alveolar rhabdomyosarcoma is characterized by the t(2;13)(q35;q14) translocation, generating the PAX3-FOXO1 fusion protein. This subtype generally carries a worse prognosis compared to embryonal rhabdomyosarcoma.

Question 6510

Topic: 10. Pathology and Oncology

A 65-year-old female presents with a large mass in her posterior thigh. Core needle biopsy demonstrates a well-differentiated liposarcoma (atypical lipomatous tumor).

Which molecular marker amplification is diagnostic for this entity?

. SYT-SSX
. MDM2
. EWSR1
. c-KIT
. BRAF

Correct Answer & Explanation

. MDM2

Explanation

Well-differentiated liposarcomas and dedifferentiated liposarcomas are characterized by the amplification of MDM2 and CDK4 genes on chromosome 12q13-15. MDM2 acts to inhibit the p53 tumor suppressor pathway.

Question 6511

Topic: 10. Pathology and Oncology

When planning surgical resection of a high-grade, undifferentiated pleomorphic sarcoma of the thigh, which of the following constitutes an adequate "wide" surgical margin?

. Enucleation through the pseudocapsule
. Resection including the pseudocapsule but preserving the reactive zone
. Resection with an intact continuous cuff of normal, healthy tissue in all directions
. Amputation at the joint proximal to the tumor
. Marginal resection followed by intraoperative wound wash with distilled water

Correct Answer & Explanation

. Resection with an intact continuous cuff of normal, healthy tissue in all directions

Explanation

A "wide" surgical margin requires removing the tumor completely intact along with a continuous surrounding cuff of normal, healthy tissue. The pseudocapsule and reactive zone often contain microscopic satellite tumor cells and must be resected.

Question 6512

Topic: Bone Tumors

A 16-year-old male presents with right knee pain. Radiographs show a lytic, well-circumscribed lesion in the proximal tibial epiphysis. MRI demonstrates fluid-fluid levels within the lesion.

Biopsy confirms sheets of mononuclear cells with grooved nuclei. Which of the following is the most likely diagnosis?

. Giant cell tumor of bone
. Chondroblastoma with secondary aneurysmal bone cyst
. Clear cell chondrosarcoma
. Telangiectatic osteosarcoma
. Primary aneurysmal bone cyst

Correct Answer & Explanation

. Chondroblastoma with secondary aneurysmal bone cyst

Explanation

Chondroblastoma typically presents as an epiphyseal lytic lesion in young patients. Secondary aneurysmal bone cysts (ABCs), characterized by fluid-fluid levels on MRI, occur in up to 20-30% of chondroblastomas.

Question 6513

Topic: 10. Pathology and Oncology

A 35-year-old female presents with a slowly enlarging, painless mass in the deep tissues of her posterior thigh. Core needle biopsy reveals extra-abdominal fibromatosis. Which of the following is the currently recommended first-line management for an asymptomatic lesion in this location?

. Wide local excision with 2 cm margins
. Marginal excision followed by adjuvant radiation
. Active observation with serial clinical and MRI evaluations
. Systemic chemotherapy with doxorubicin and ifosfamide
. Preoperative radiation therapy followed by wide excision

Correct Answer & Explanation

. Active observation with serial clinical and MRI evaluations

Explanation

Active observation is the first-line management for asymptomatic, non-life-threatening extra-abdominal fibromatosis (desmoid tumors). Many of these tumors exhibit prolonged periods of stability or even spontaneous regression.

Question 6514

Topic: 10. Pathology and Oncology

A 24-year-old male presents with a deep, slow-growing mass in his foot. Radiographs show stippled calcifications within the soft tissue mass. Biopsy reveals a biphasic pattern of spindle and epithelial cells. Which of the following chromosomal translocations is diagnostic?

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

Correct Answer & Explanation

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

Explanation

Synovial sarcoma classically presents in the distal extremities of young adults and may contain calcifications in up to 30% of cases. It is driven by the t(X;18) translocation resulting in the SYT-SSX fusion gene.

Question 6515

Topic: Soft Tissue Tumors & Metastasis

A 45-year-old male is diagnosed with a 12 cm deep myxoid liposarcoma of the thigh. As part of his systemic staging workup, which of the following imaging modalities is uniquely indicated for this specific histologic subtype?

. PET/CT scan of the whole body
. MRI of the total spine
. CT scan of the brain with contrast
. Bone scintigraphy (Tc-99m)
. Ultrasound of the regional lymph nodes

Correct Answer & Explanation

. MRI of the total spine

Explanation

Myxoid liposarcoma has a unique propensity to metastasize to extrapulmonary locations, particularly the spine and other bones. Total spine MRI is standard in the staging workup for this specific subtype.

Question 6516

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a firm mass in her abdominal wall. She has a family history of Gardner syndrome. Her biopsy confirms a desmoid tumor. Germline mutation in which of the following genes is most likely responsible for her condition?

. CTNNB1
. APC
. TP53
. NF1
. RB1

Correct Answer & Explanation

. APC

Explanation

Gardner syndrome is a phenotypic variant of Familial Adenomatous Polyposis (FAP) caused by germline mutations in the APC gene. It strongly predisposes patients to developing desmoid fibromatosis.

Question 6517

Topic: 10. Pathology and Oncology

A 21-year-old male develops a multi-lobulated, ulcerating mass on the palmar aspect of his right hand. Examination reveals palpable axillary lymphadenopathy. Histologic analysis shows epithelioid cells with a loss of SMARCB1 (INI1) expression. What is the most likely diagnosis?

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

Correct Answer & Explanation

. Epithelioid sarcoma

Explanation

Epithelioid sarcoma typically presents in the distal extremities (hand/wrist) of young adults, often ulcerates mimicking a benign process, and has a high rate of lymphatic spread. Loss of INI1 is a characteristic immunohistochemical finding.

Question 6518

Topic: 10. Pathology and Oncology

A 19-year-old male underwent extended curettage and bone grafting for a proximal humerus chondroblastoma 2 years ago. He now presents with a routine surveillance chest CT showing multiple small, well-circumscribed, calcified lung nodules. He is asymptomatic. What is the most appropriate management of the pulmonary findings?

. Initiate systemic doxorubicin-based chemotherapy
. Immediate bilateral pulmonary metastasectomy
. Palliative radiation to the lung fields
. Observation, as these represent benign metastatic implants
. Hospice care due to advanced metastatic disease

Correct Answer & Explanation

. Observation, as these represent benign metastatic implants

Explanation

Chondroblastoma is a benign tumor that can rarely metastasize to the lungs (benign pulmonary implants). These implants are often slow-growing or non-progressive, and asymptomatic lesions can typically be observed.

Question 6519

Topic: 10. Pathology and Oncology

A 68-year-old male presents with a rapidly growing, painless mass in the superficial subcutaneous tissues of his thigh. MRI reveals a lobulated mass with a characteristic "tail-like" extension along the fascial planes. What is the most likely histologic diagnosis?

. Lipoma
. Myxofibrosarcoma
. Undifferentiated pleomorphic sarcoma
. Leiomyosarcoma
. Malignant peripheral nerve sheath tumor

Correct Answer & Explanation

. Myxofibrosarcoma

Explanation

Myxofibrosarcoma commonly presents as a superficial mass in elderly patients. Its classic MRI feature is a 'fascial tail' representing infiltrative tumor spread, which contributes to a high rate of local recurrence if margins are inadequate.

Question 6520

Topic: 10. Pathology and Oncology

A 30-year-old female presents with an enlarging mass deep to the Achilles tendon.

Biopsy demonstrates nests of uniform spindle cells that stain strongly positive for S-100 and HMB-45. Which of the following translocations is associated with this tumor?

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

Correct Answer & Explanation

. t(12;22)(q13;q12)

Explanation

Clear cell sarcoma (melanoma of soft parts) typically arises in association with tendons and aponeuroses of the foot and ankle. It is characterized by t(12;22) resulting in the EWSR1-ATF1 fusion and stains positive for melanocytic markers.

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