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10. Pathology and Oncology MCQs

Practice Set 325 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 6481

Topic: 10. Pathology and Oncology

Which magnetic resonance imaging (MRI) feature is highly characteristic of extra-abdominal desmoid tumors, directly reflecting their dense collagenous composition?

. Homogeneous extreme hyperintensity on all T1-weighted images
. Prominent fluid-fluid levels on T2-weighted images
. Band-like low-signal intensity regions within the tumor on T2-weighted images
. Massive central necrosis with a thin rim of enhancement
. Complete suppression of intralesional signal on STIR sequences

Correct Answer & Explanation

. Band-like low-signal intensity regions within the tumor on T2-weighted images

Explanation

Desmoid tumors typically exhibit low-signal intensity 'bands' on T2-weighted MRI. These bands correspond histologically to dense, hypocellular collagen bundles interspersed within the more cellular portions of the fibromatosis.

Question 6482

Topic: 10. Pathology and Oncology

A 45-year-old man presents with a deep, painless, 8 cm mass in his anterior thigh. An MRI suggests a soft tissue sarcoma. When planning an incisional biopsy, which of the following is the most critical technical principle?

. Avoid obtaining samples from the tumor periphery
. Achieve meticulous hemostasis to prevent tumor tracking in a hematoma
. Utilize a transverse incision to minimize scar tension
. Use a tourniquet and exsanguinate the limb before biopsy
. Route the biopsy tract through uninvolved compartments for best healing

Correct Answer & Explanation

. Achieve meticulous hemostasis to prevent tumor tracking in a hematoma

Explanation

Meticulous hemostasis is critical during sarcoma biopsy to prevent the dissemination of tumor cells via a hematoma. Incisions should be longitudinal, not transverse, and compartmental boundaries must not be violated.

Question 6483

Topic: 10. Pathology and Oncology

A 32-year-old woman presents with an enlarging, painless mass in her right posteromedial thigh. Core needle biopsy confirms extra-abdominal aggressive fibromatosis (desmoid tumor).

She has no neurovascular deficits. What is the currently recommended initial management?

. Active surveillance (watchful waiting)
. Wide local excision with negative margins
. Neoadjuvant external beam radiotherapy followed by wide excision
. Immediate amputation to prevent systemic metastasis
. Intralesional curettage and cementation

Correct Answer & Explanation

. Active surveillance (watchful waiting)

Explanation

Current consensus favors active surveillance as the first-line management for asymptomatic extra-abdominal desmoid tumors, as many remain stable or spontaneously regress. Surgery is reserved for progressive or highly symptomatic lesions due to high recurrence rates.

Question 6484

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a slow-growing, deep-seated soft tissue mass near the knee joint. Biopsy reveals a biphasic spindle cell and epithelial tumor. Which of the following genetic translocations is pathognomonic for this lesion?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma classically exhibits the t(X;18) translocation resulting in the SYT-SSX fusion gene. It commonly presents in young adults near joints but rarely involves the intra-articular space.

Question 6485

Topic: 10. Pathology and Oncology

Extra-abdominal aggressive fibromatosis (desmoid tumor) occurs most frequently as a sporadic lesion but can be associated with which of the following inherited syndromes?

. Neurofibromatosis type 1
. Li-Fraumeni syndrome
. Gardner syndrome
. Multiple Hereditary Exostoses
. McCune-Albright syndrome

Correct Answer & Explanation

. Gardner syndrome

Explanation

Aggressive fibromatosis is strongly associated with Gardner syndrome, a variant of Familial Adenomatous Polyposis (FAP) caused by mutations in the APC gene. Sporadic cases typically harbor mutations in the CTNNB1 (beta-catenin) gene.

Question 6486

Topic: 10. Pathology and Oncology

In the multidisciplinary management of high-grade extremity soft tissue sarcomas, a primary advantage of preoperative radiation therapy compared to postoperative radiation therapy is:

. Decreased incidence of major wound complications
. Lower total radiation dose and smaller treatment field
. Elimination of the need for surgical resection
. Decreased rate of systemic metastasis
. Improved histologic grading on the definitive surgical specimen

Correct Answer & Explanation

. Lower total radiation dose and smaller treatment field

Explanation

Preoperative radiation therapy allows for a smaller treatment field and lower total dose compared to postoperative RT, decreasing late complications like joint stiffness and fibrosis. However, it carries a significantly higher risk of acute postoperative wound complications.

Question 6487

Topic: 10. Pathology and Oncology

A 16-year-old female undergoes curettage of a distal femoral chondroblastoma. Two years later, she is found to have two 1-cm asymptomatic pulmonary nodules. Biopsy of a nodule confirms chondroblastoma. What is the most appropriate management?

. Palliative care only
. Systemic chemotherapy with doxorubicin and cisplatin
. Whole-lung irradiation
. Surgical resection of the pulmonary nodules
. Radiofrequency ablation of the primary femoral site

Correct Answer & Explanation

. Surgical resection of the pulmonary nodules

Explanation

Chondroblastoma is a benign tumor that occasionally metastasizes to the lungs (benign pulmonary implants). These implants are typically non-progressive or slow-growing, and surgical resection is the treatment of choice, carrying an excellent long-term prognosis.

Question 6488

Topic: 10. Pathology and Oncology

A 35-year-old female presents with a painless, palpable mass in her posterior thigh.

Core needle biopsy reveals bland, uniform spindle cells arranged in sweeping fascicles with abundant collagen and no nuclear atypia. Which of the following represents the most currently accepted initial management strategy for this asymptomatic lesion?

. Immediate wide surgical excision
. Radiation therapy alone
. Active surveillance (wait-and-see)
. Neoadjuvant doxorubicin-based chemotherapy
. Forequarter amputation

Correct Answer & Explanation

. Active surveillance (wait-and-see)

Explanation

Extra-abdominal aggressive fibromatosis (desmoid tumors) often have an unpredictable course, including spontaneous regression. Current consensus guidelines recommend an initial period of active surveillance for asymptomatic tumors before initiating medical therapy or surgery.

Question 6489

Topic: 10. Pathology and Oncology

When performing an incisional biopsy of a suspected soft tissue sarcoma in the extremity, which of the following technical principles MUST be strictly adhered to?

. The biopsy tract should be placed transverse to the extremity axis
. Meticulous hemostasis is unnecessary if a drain is placed
. The biopsy incision must be placed in-line with the planned definitive resection
. A tourniquet should be exsanguinated and inflated before making the incision
. Dissection should expose major neurovascular bundles to confirm their safety

Correct Answer & Explanation

. The biopsy incision must be placed in-line with the planned definitive resection

Explanation

Biopsy incisions for suspected sarcomas must be longitudinal and placed in-line with the planned definitive surgical incision so the entire tract can be excised en bloc. Transverse incisions contaminate wider tissue planes and complicate definitive wide excision.

Question 6490

Topic: 10. Pathology and Oncology

A 65-year-old man presents with a large, deep intramuscular thigh mass.

Molecular testing of the biopsy specimen demonstrates amplification of the MDM2 and CDK4 genes. What is the most likely diagnosis?

. Synovial sarcoma
. Myxoid liposarcoma
. Pleomorphic rhabdomyosarcoma
. Well-differentiated liposarcoma
. Clear cell sarcoma

Correct Answer & Explanation

. Well-differentiated liposarcoma

Explanation

Well-differentiated liposarcoma (atypical lipomatous tumor) and dedifferentiated liposarcoma are characterized by the amplification of MDM2 and CDK4 on chromosome 12. This distinguishes them from benign lipomas, which lack this amplification.

Question 6491

Topic: Bone Tumors

Which of the following secondary lesions is most frequently associated with a chondroblastoma?

. Osteoid osteoma
. Aneurysmal bone cyst
. Unicameral bone cyst
. Non-ossifying fibroma
. Osteosarcoma

Correct Answer & Explanation

. Aneurysmal bone cyst

Explanation

Approximately 15% to 20% of chondroblastomas are associated with a secondary aneurysmal bone cyst (ABC). Recognition of both components is critical to ensure thorough curettage and minimize the risk of recurrence.

Question 6492

Topic: 10. Pathology and Oncology

According to current orthopedic oncology principles, what defines a "wide" surgical margin for a high-grade soft tissue sarcoma?

. Excision of the tumor leaving microscopic residual disease
. Excision of the tumor through the pseudocapsule
. Excision of the tumor along with a continuous cuff of normal surrounding tissue
. Removal of the entire anatomic compartment containing the tumor
. Complete amputation of the affected limb

Correct Answer & Explanation

. Excision of the tumor along with a continuous cuff of normal surrounding tissue

Explanation

A wide margin involves removing the tumor completely enclosed within a continuous cuff of normal surrounding tissue. Intralesional and marginal excisions leave macroscopic or microscopic disease, respectively, while a radical margin involves removing the entire compartment.

Question 6493

Topic: 10. Pathology and Oncology

A patient with recurrent, progressive extra-abdominal fibromatosis (desmoid tumor) has failed initial active surveillance. Based on recent clinical trials, which of the following oral targeted therapies is considered a first-line medical treatment?

. Imatinib
. Sorafenib
. Denosumab
. Erlotinib
. Crizotinib

Correct Answer & Explanation

. Sorafenib

Explanation

Sorafenib, a multi-kinase inhibitor, has demonstrated significant progression-free survival benefits in patients with progressive, unresectable desmoid tumors. Other active targeted agents include gamma-secretase inhibitors like nirogacestat.

Question 6494

Topic: 10. Pathology and Oncology

A 45-year-old male is diagnosed with an extremity soft tissue sarcoma. Staging imaging must routinely include the chest because the lungs are the most common site of metastasis. Which of the following soft tissue sarcomas requires additional whole-spine MRI screening due to its propensity for extrapulmonary bone metastases?

. Synovial sarcoma
. Epithelioid sarcoma
. Pleomorphic sarcoma
. Myxoid liposarcoma
. Fibrosarcoma

Correct Answer & Explanation

. Myxoid liposarcoma

Explanation

Myxoid liposarcoma is unique among soft tissue sarcomas for its high propensity to metastasize to extrapulmonary sites, particularly the spine and other bones. Therefore, staging protocols for this tumor must include cross-sectional imaging (MRI) of the whole spine.

Question 6495

Topic: 10. Pathology and Oncology

A biopsy of a soft tissue tumor demonstrates the t(12;16) translocation resulting in a FUS-DDIT3 fusion protein. Which of the following histologic features is classically associated with this tumor?

. Biphasic spindle and epithelial cells
. Plexiform vascular pattern with lipoblasts in a myxoid background
. Herringbone pattern of atypical spindle cells
. Sheets of small round blue cells with rosette formation
. Large pleomorphic cells with prominent eosinophilic cytoplasm

Correct Answer & Explanation

. Plexiform vascular pattern with lipoblasts in a myxoid background

Explanation

The t(12;16) translocation and FUS-DDIT3 fusion are diagnostic for myxoid liposarcoma. Histologically, it is characterized by a prominent myxoid stroma, a rich plexiform (chicken-wire) capillary network, and varying numbers of lipoblasts.

Question 6496

Topic: 10. Pathology and Oncology

Which of the following soft tissue sarcomas is most notorious for spreading via the lymphatic system, thereby necessitating clinical or radiographic evaluation of the regional lymph nodes?

. Undifferentiated pleomorphic sarcoma
. Well-differentiated liposarcoma
. Epithelioid sarcoma
. Dermatofibrosarcoma protuberans
. Leiomyosarcoma

Correct Answer & Explanation

. Epithelioid sarcoma

Explanation

Sarcomas that commonly metastasize to lymph nodes can be remembered by the mnemonic SCARE: Synovial, Clear cell, Angiosarcoma, Rhabdomyosarcoma, and Epithelioid sarcoma. Epithelioid sarcoma has one of the highest rates of lymphatic spread.

Question 6497

Topic: 10. Pathology and Oncology

A patient presents with an aggressive fibromatosis (desmoid tumor) in the shoulder girdle. Immunohistochemistry of the biopsy specimen will most consistently demonstrate strong nuclear staining for which of the following proteins?

. S-100
. SMA (Smooth Muscle Actin)
. Beta-catenin
. Desmin
. CD34

Correct Answer & Explanation

. Beta-catenin

Explanation

Aberrant nuclear localization of beta-catenin is the hallmark immunohistochemical feature of desmoid tumors. This is driven by mutations in either the CTNNB1 gene or the APC gene, which prevent the normal degradation of beta-catenin.

Question 6498

Topic: 10. Pathology and Oncology

A 16-year-old male presents with chronic right shoulder pain. Radiographs reveal an eccentric, lytic lesion in the proximal humeral epiphysis with a thin sclerotic rim.

Biopsy confirms a benign cartilaginous tumor. What is the most common cytogenetic abnormality associated with this specific lesion?

. t(11;22)(q24;q12)
. H3F3A or H3F3B K36M mutation
. t(X;18)(p11;q11)
. MDM2 amplification
. H3F3A G34W mutation

Correct Answer & Explanation

. H3F3A or H3F3B K36M mutation

Explanation

Chondroblastoma characteristically harbors an H3F3A or H3F3B K36M mutation. Giant cell tumors of bone, which can also appear in the epiphysis, typically exhibit an H3F3A G34W mutation.

Question 6499

Topic: 10. Pathology and Oncology

A 24-year-old male presents with a slow-growing, painful mass near his knee joint. MRI shows a well-defined mass adjacent to the joint capsule, and biopsy confirms a biphasic tumor with both epithelial and spindle cell components. Which chromosomal translocation is diagnostic for this tumor?

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

Correct Answer & Explanation

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

Explanation

Synovial sarcoma is uniquely characterized by the t(X;18)(p11;q11) translocation, which creates the SYT-SSX fusion gene. It often presents in young adults near large joints and can exhibit biphasic or monophasic histology.

Question 6500

Topic: 10. Pathology and Oncology

A 28-year-old postpartum female presents with a slowly enlarging, mildly symptomatic mass in her anterior abdominal wall. Core biopsy confirms extra-abdominal fibromatosis.

According to current treatment guidelines, what is the most appropriate initial management?

. Wide local excision with negative margins
. Preoperative radiation therapy
. Active observation with serial MRIs
. Methotrexate and vinblastine chemotherapy
. Immediate radiofrequency ablation

Correct Answer & Explanation

. Active observation with serial MRIs

Explanation

Active observation (a "wait-and-see" approach) is now the recommended first-line management for asymptomatic or mildly symptomatic desmoid tumors. Spontaneous regression is observed in up to 20-30% of cases, particularly those associated with pregnancy.

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