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10. Pathology and Oncology MCQs

Practice Set 324 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 6461

Topic: 10. Pathology and Oncology

A 5-year-old child presents with a rapidly enlarging, painless mass in the forearm. A biopsy confirms the most common soft tissue sarcoma of childhood. Histologic subtypes of this tumor carry distinct prognostic implications. The alveolar subtype, which generally has a worse prognosis, is characterized by which specific translocation?

. t(11;22)(q24;q12)
. t(2;13)(q35;q14)
. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(9;22)(q34;q11)

Correct Answer & Explanation

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

Explanation

The most common soft tissue sarcoma in children is rhabdomyosarcoma. The alveolar subtype is more aggressive than the embryonal subtype and is genetically characterized by the t(2;13)(q35;q14) translocation, producing the PAX3-FOXO1 fusion protein.

Question 6462

Topic: 10. Pathology and Oncology

A 19-year-old female presents with a lytic epiphyseal lesion of the proximal tibia. Biopsy confirms chondroblastoma. The surgeon plans intralesional curettage. Which of the following intraoperative techniques is most strongly associated with a reduced risk of local recurrence for this tumor?

. Use of a tourniquet without exsanguination
. Aggressive high-speed burring of the cavity walls
. Packing the defect strictly with allograft rather than autograft
. Avoidance of chemical adjuvants to preserve the subchondral bone
. Performing the curettage through an osteochondral window

Correct Answer & Explanation

. Aggressive high-speed burring of the cavity walls

Explanation

For benign but locally aggressive bone tumors like chondroblastoma and giant cell tumor, simple curettage leaves microscopic disease. Extended curettage using a high-speed burr to break the reactive bony rim, often followed by a chemical adjuvant, significantly decreases the local recurrence rate.

Question 6463

Topic: 10. Pathology and Oncology

A 22-year-old female presents with a slow-growing mass in her thigh. Imaging reveals a hypervascular soft tissue mass. Biopsy demonstrates large polygonal cells with prominent nucleoli and an alveolar growth pattern. A diagnostic cytogenetic workup reveals a t(X;17) translocation resulting in an ASPSCR1-TFE3 fusion. Despite a slow local growth rate, what highly characteristic pattern of metastasis requires immediate evaluation?

. Widespread osteoblastic bone metastases
. Early involvement of the axillary lymph nodes
. Frequent and early metastases to the brain and lungs
. Isolated liver metastases
. Diffuse leptomeningeal spread

Correct Answer & Explanation

. Frequent and early metastases to the brain and lungs

Explanation

The diagnosis is Alveolar Soft Part Sarcoma (ASPS), characterized by the ASPSCR1-TFE3 fusion. Despite a deceptively slow-growing primary tumor, ASPS has a notorious propensity for early and frequent metastasis to the lungs and brain, mandating brain MRI and chest CT during initial staging.

Question 6464

Topic: 10. Pathology and Oncology

A 15-year-old male presents with knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion in the proximal tibia. Biopsy shows mononuclear polygonal cells with nuclear grooves and areas of eosinophilic matrix. Which of the following is the hallmark histological pattern of mineralization in this tumor?

. Popcorn calcification
. Chicken-wire calcification
. Ring-and-arc calcification
. Sunburst ossification
. Woven bone formation

Correct Answer & Explanation

. Chicken-wire calcification

Explanation

Chondroblastoma is a benign cartilage tumor characterized histologically by polygonal mononuclear cells (chondroblasts) with grooved 'coffee-bean' nuclei. Fine, pericellular calcifications known as 'chicken-wire' calcifications are pathognomonic.

Question 6465

Topic: 10. Pathology and Oncology

A 15-year-old male presents with chronic knee pain. Radiographs reveal a well-circumscribed, lytic epiphyseal lesion in the distal femur. A biopsy is performed. Histologically, the lesion shows mononuclear cells with longitudinal nuclear grooves and 'chicken-wire' intercellular calcifications. What is the most likely diagnosis?

. Giant cell tumor
. Chondromyxoid fibroma
. Chondroblastoma
. Clear cell chondrosarcoma
. Osteoblastoma

Correct Answer & Explanation

. Chondroblastoma

Explanation

Chondroblastoma typically occurs in the epiphysis of skeletally immature patients. Histology characteristically reveals chondroblasts (mononuclear cells with clefted nuclei) surrounded by fine, lacelike 'chicken-wire' calcifications. Giant cell tumors usually occur after physeal closure.

Question 6466

Topic: 10. Pathology and Oncology

When performing an incisional biopsy for a suspected high-grade soft tissue sarcoma of the anterior thigh, which of the following is an absolute surgical principle?

. Utilize a transverse incision to minimize skin tension
. Perform an excisional biopsy if the lesion is greater than 5 cm
. Make a longitudinal incision in line with the underlying muscle fibers
. Route the biopsy tract through adjacent compartments to avoid neurovascular bundles
. Exsanguinate the limb with an Esmarch bandage prior to applying a tourniquet

Correct Answer & Explanation

. Make a longitudinal incision in line with the underlying muscle fibers

Explanation

Biopsy incisions for sarcomas must be longitudinal and in line with muscle fibers to allow for en bloc excision of the biopsy tract during definitive wide resection. Transverse incisions contaminate wider tissue planes and complicate definitive limb-sparing surgery. Exsanguination via Esmarch should be avoided to prevent tumor embolization.

Question 6467

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a deep, firm, and fixed mass in her shoulder girdle. Core needle biopsy confirms extra-abdominal aggressive fibromatosis (desmoid tumor). Which genetic alteration is most commonly implicated in the pathogenesis of this tumor?

. SYT-SSX translocation
. MDM2 amplification
. Beta-catenin (CTNNB1) mutation
. RB1 deletion
. EWS-FLI1 fusion

Correct Answer & Explanation

. Beta-catenin (CTNNB1) mutation

Explanation

Desmoid tumors (fibromatoses) are strongly associated with mutations in the Wnt/beta-catenin signaling pathway, most commonly a CTNNB1 (beta-catenin) gene mutation in sporadic cases. In familial cases, they are associated with APC gene mutations (Gardner syndrome).

Question 6468

Topic: 10. Pathology and Oncology

A 16-year-old male is diagnosed with an active chondroblastoma of the proximal humerus causing significant joint pain and subchondral erosion. What is the most appropriate initial surgical management?

. Wide en bloc resection with endoprosthetic reconstruction
. Extended intralesional curettage, chemical adjuvant, and bone grafting
. Neoadjuvant chemotherapy followed by marginal excision
. Amputation at the level of the glenohumeral joint
. Primary radiation therapy to 50 Gy

Correct Answer & Explanation

. Extended intralesional curettage, chemical adjuvant, and bone grafting

Explanation

Chondroblastoma is a benign but locally aggressive bone tumor. The standard of care is extended intralesional curettage, often utilizing a high-speed burr and adjuvants (like phenol or liquid nitrogen), followed by packing with bone graft or PMMA cement.

Question 6469

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a slowly growing, painful mass deep within the vastus medialis near the knee joint. Biopsy reveals a biphasic tumor comprised of epithelial and spindle cell components. What is the characteristic cytogenetic abnormality for this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The clinical and histologic description represents a synovial sarcoma, which frequently arises near joints (but rarely within them). Its pathognomonic chromosomal translocation is t(X;18), resulting in the SYT-SSX fusion gene.

Question 6470

Topic: 10. Pathology and Oncology

A 28-year-old female is incidentally diagnosed with an asymptomatic 4 cm extra-abdominal desmoid tumor in the posterior thigh musculature. Based on current consensus guidelines, what is the most appropriate initial management strategy?

. Wide surgical resection with negative margins
. Marginal excision combined with adjuvant radiotherapy
. Active surveillance with serial MRI
. Multi-agent systemic chemotherapy
. Immediate radiofrequency ablation

Correct Answer & Explanation

. Active surveillance with serial MRI

Explanation

The treatment paradigm for desmoid tumors has shifted significantly away from upfront morbid surgery. The current recommended first-line approach for asymptomatic or minimally symptomatic tumors is active surveillance ('watch and wait'), as many tumors stabilize or spontaneously regress.

Question 6471

Topic: 10. Pathology and Oncology

In the surgical management of soft tissue sarcomas, how is a 'wide' surgical margin accurately defined?

. Excision directly through the tumor pseudocapsule
. Excision passing continuously through a cuff of normal, healthy tissue surrounding the tumor
. Removal of the entire anatomic muscular compartment containing the tumor from origin to insertion
. Complete removal of the tumor along with a 5 cm margin of overlying skin
. Excision that deliberately leaves microscopic disease at neurovascular borders

Correct Answer & Explanation

. Excision passing continuously through a cuff of normal, healthy tissue surrounding the tumor

Explanation

A wide margin involves excising the tumor completely encompassed within a continuous envelope (cuff) of normal tissue. It does not require removal of the entire anatomical compartment (radical margin), but must avoid breaching the reactive pseudocapsule where satellite cells reside.

Question 6472

Topic: 10. Pathology and Oncology

When multidisciplinary treatment involves radiation for a high-grade extremity soft tissue sarcoma, what is a primary advantage of preoperative radiotherapy compared to postoperative radiotherapy?

. Lower incidence of acute wound healing complications
. Lower total radiation dose and a smaller treatment field
. Superior overall patient survival rates
. Decreased risk of local recurrence
. Elimination of the necessity for surgical resection

Correct Answer & Explanation

. Lower total radiation dose and a smaller treatment field

Explanation

Preoperative radiotherapy allows for a smaller treatment field and lower total dose (typically 50 Gy) compared to postoperative RT (typically 60-66 Gy), which reduces long-term limb edema and fibrosis. However, it is associated with a significantly higher rate of acute surgical wound complications.

Question 6473

Topic: 10. Pathology and Oncology

A 35-year-old male with a previously observed desmoid tumor of the shoulder girdle now presents with rapid growth, severe pain, and progressive neurologic deficit. Surgical morbidity would be extreme. Which targeted medical therapy is highly effective and increasingly utilized for progressive fibromatosis?

. Doxorubicin
. Denosumab
. Sorafenib
. Methotrexate
. Rituximab

Correct Answer & Explanation

. Sorafenib

Explanation

For progressive or symptomatic desmoid tumors where surgery would be highly morbid, medical management is preferred. Sorafenib, a tyrosine kinase inhibitor, has shown high efficacy in halting progression and inducing responses in advanced desmoid tumors.

Question 6474

Topic: Soft Tissue Tumors & Metastasis

A 65-year-old man undergoes resection of a massive, deep intramuscular thigh mass. Pathology demonstrates a dedifferentiated liposarcoma. Which molecular marker is most characteristically amplified in well-differentiated and dedifferentiated liposarcomas?

. c-MYC
. HER2
. MDM2
. p53
. BRAF

Correct Answer & Explanation

. MDM2

Explanation

Well-differentiated and dedifferentiated liposarcomas are characterized by supernumerary ring and giant marker chromosomes containing amplification of the 12q13-15 region. This leads to the characteristic over-expression/amplification of MDM2 and CDK4.

Question 6475

Topic: 10. Pathology and Oncology

Although primarily considered a benign bone tumor, chondroblastoma has a known, rare potential to metastasize (so-called 'benign metastasis'). To which organ does it most commonly metastasize?

. Liver
. Brain
. Lungs
. Regional lymph nodes
. Axial spine

Correct Answer & Explanation

. Lungs

Explanation

Chondroblastoma can occasionally undergo 'benign metastasis', almost exclusively to the lungs. These pulmonary metastases are histologically identical to the primary benign tumor and can often be cured with surgical wedge resection.

Question 6476

Topic: 10. Pathology and Oncology

In determining the prognosis and risk of distant metastasis for a patient with a newly diagnosed primary extremity soft tissue sarcoma, what is generally considered the single most important prognostic factor?

. Maximum tumor dimension
. Anatomical depth of the tumor
. Histologic tumor grade
. Patient age at diagnosis
. Baseline nodal status

Correct Answer & Explanation

. Histologic tumor grade

Explanation

Histologic grade is the most critical prognostic factor for predicting distant metastasis and overall survival in soft tissue sarcomas. While tumor size and depth are also important staging parameters, grade remains the primary determinant of tumor biology.

Question 6477

Topic: 10. Pathology and Oncology

A patient presenting with multiple extra-abdominal and intra-abdominal desmoid tumors should be highly suspected of having, and screened for, which of the following underlying conditions?

. Neurofibromatosis Type 1
. Familial Adenomatous Polyposis (FAP)
. Li-Fraumeni syndrome
. Multiple Endocrine Neoplasia type 2
. Hereditary Retinoblastoma

Correct Answer & Explanation

. Familial Adenomatous Polyposis (FAP)

Explanation

Multiple desmoid tumors, especially involving the abdomen, are a hallmark of Gardner syndrome, a phenotypic variant of Familial Adenomatous Polyposis (FAP) caused by an APC gene mutation. These patients require colonoscopy to screen for colon cancer.

Question 6478

Topic: 10. Pathology and Oncology

A 22-year-old female is diagnosed with an alveolar soft part sarcoma (ASPS) of the right thigh. Which site of metastasis is uncharacteristically common in this specific sarcoma subtype compared to the general population of soft tissue sarcomas?

. Cortical bone
. Liver parenchyma
. Brain
. Cutaneous tissue
. Contralateral extremity muscles

Correct Answer & Explanation

. Brain

Explanation

While the lungs are the most common site of metastasis for almost all soft tissue sarcomas, alveolar soft part sarcoma (ASPS) has an unusually high predilection for brain metastases compared to other soft tissue sarcomas. Staging should routinely include brain imaging.

Question 6479

Topic: 10. Pathology and Oncology

Both chondroblastoma and clear cell chondrosarcoma typically present radiographically as epiphyseal lytic lesions. Which clinical feature best helps differentiate between the two entities prior to definitive biopsy?

. Chondroblastoma typically occurs in skeletally mature patients over age 40
. Clear cell chondrosarcoma typically presents in skeletally immature children
. Chondroblastoma almost exclusively occurs in the 2nd decade of life prior to physeal closure
. Clear cell chondrosarcoma is universally a polyostotic disease process
. Chondroblastoma exclusively affects the small tubular bones of the hands and feet

Correct Answer & Explanation

. Chondroblastoma almost exclusively occurs in the 2nd decade of life prior to physeal closure

Explanation

Age is the critical differentiator. Chondroblastoma occurs almost exclusively in skeletally immature patients (typically ages 10-20), whereas clear cell chondrosarcoma typically presents in adults (ages 20-50) after physeal closure.

Question 6480

Topic: 10. Pathology and Oncology

The vast majority of soft tissue sarcomas metastasize hematogenously to the lungs. However, certain subtypes have a significantly higher propensity for lymphatic spread. Which of the following soft tissue sarcomas belongs to this group?

. Myxoid liposarcoma
. Pleomorphic liposarcoma
. Dermatofibrosarcoma protuberans
. Epithelioid sarcoma
. Adult fibrosarcoma

Correct Answer & Explanation

. Epithelioid sarcoma

Explanation

A useful mnemonic for sarcomas that metastasize to lymph nodes is SCARE: Synovial, Clear cell, Angiosarcoma, Rhabdomyosarcoma, and Epithelioid sarcoma. Epithelioid sarcoma often spreads via lymphatics and may present with regional nodal disease.

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