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10. Pathology and Oncology MCQs

Practice Set 117 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 2321

Topic: 10. Pathology and Oncology
A 55-year-old male presents with severe unremitting thigh pain. Radiographs demonstrate a destructive diaphyseal lesion with prominent endosteal scalloping and cortical breakthrough. Biopsy reveals a lobular architecture of atypical cartilaginous cells in a myxoid matrix. Which of the following is the standard treatment for a conventional grade II chondrosarcoma?
. Neoadjuvant chemotherapy followed by wide resection
. Definitive radiation therapy
. Intralesional curettage, phenol adjuvant, and bone grafting
. Wide surgical resection alone
. Denosumab therapy followed by intralesional curettage

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcoma is notoriously resistant to both chemotherapy and radiation. The mainstay of treatment for intermediate and high-grade (Grade II/III) chondrosarcoma is wide surgical resection.

Question 2322

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a painful mid-shaft femur mass. Radiographs show a permeative, diaphyseal lytic lesion with an "onion-skin" periosteal reaction. Core biopsy reveals small round blue cells. Cytogenetics demonstrate a t(11;22) translocation. What is the fusion protein generated by this translocation?

. SYT-SSX
. EWS-FLI1
. TLS-CHOP
. PAX3-FKHR
. COL1A1-PDGFB

Correct Answer & Explanation

. EWS-FLI1

Explanation

The t(11;22) translocation is classic for Ewing sarcoma and results in the EWS-FLI1 fusion protein. SYT-SSX is seen in synovial sarcoma, and TLS-CHOP is associated with myxoid liposarcoma.

Question 2323

Topic: 10. Pathology and Oncology
A 15-year-old female undergoes neoadjuvant chemotherapy followed by wide resection of a distal femur osteosarcoma. Histologic evaluation of the resected tumor specimen is performed to assess the extent of necrosis. According to the Huvos grading system, what percentage of tumor necrosis is the threshold for a "good" response to chemotherapy, correlating with improved survival?
. 50%
. 70%
. 90%
. 95%
. 99%

Correct Answer & Explanation

. 90%

Explanation

A 90% or greater tumor necrosis rate (Huvos Grade III or IV) following neoadjuvant chemotherapy is considered a good histologic response. This is the single most important prognostic factor for long-term survival in high-grade osteosarcoma.

Question 2324

Topic: 10. Pathology and Oncology
A 58-year-old female with a history of breast cancer presents with severe, localized pain in her right humerus. X-rays reveal a lytic lesion in the proximal humerus with cortical destruction extending greater than 50%. She is ambulatory but guards her arm significantly. The Mirels' score is calculated to be 10. What is the most appropriate management strategy?
. Radiation therapy alone
. Bisphosphonates and watchful waiting
. Prophylactic intramedullary nailing
. Excisional biopsy followed by adjuvant radiation
. Open reduction internal fixation (ORIF) or prosthetic replacement

Correct Answer & Explanation

. Prophylactic intramedullary nailing

Explanation

A Mirels' score of 10 indicates a high risk of impending pathological fracture (typically >30-50% risk for scores 9-12). For high-risk impending fractures of long bones like the humerus, prophylactic surgical stabilization is recommended to prevent fracture, relieve pain, and maintain function. Intramedullary nailing is often the preferred method for humeral shaft and proximal humeral lesions, offering stable internal fixation and allowing early mobilization. Radiation therapy is typically used as an adjuvant to surgery for local control and pain relief, or as primary treatment for low-risk lesions (Mirels' ≤ 7). Excisional biopsy is generally not performed for known metastatic disease, and ORIF/prosthetic replacement would be considered for an actual fracture, not an impending one (unless the destruction is so severe as to warrant reconstruction).

Question 2325

Topic: 10. Pathology and Oncology

A 15-year-old male presents with a painful mass around his right knee. Radiographs reveal a mixed lytic and sclerotic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms high-grade intramedullary osteosarcoma. Which of the following genetic alterations is most frequently associated with the pathogenesis of this tumor?

. t(11;22) translocation
. t(X;18) translocation
. Loss of heterozygosity at the RB1 and TP53 loci
. Amplification of the MDM2 gene
. t(12;16) translocation

Correct Answer & Explanation

. Loss of heterozygosity at the RB1 and TP53 loci

Explanation

Osteosarcoma is characterized by profound, complex genomic instability, most commonly involving mutations or loss of heterozygosity in tumor suppressor genes like RB1 and TP53. In contrast, translocations like t(11;22) and t(X;18) are associated with Ewing sarcoma and synovial sarcoma, respectively.

Question 2326

Topic: 10. Pathology and Oncology

A 24-year-old female presents with a slow-growing, painful mass in her foot. MRI demonstrates a soft tissue mass with heterogeneous enhancement. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Which of the following chromosomal translocations is highly specific to this diagnosis?

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

Correct Answer & Explanation

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

Explanation

The clinical and histologic description of a biphasic mass (epithelial and spindle cells) in the distal extremity of a young adult is characteristic of synovial sarcoma. This tumor is strongly associated with the t(X;18)(p11;q11) translocation involving the SYT-SSX fusion gene.

Question 2327

Topic: 10. Pathology and Oncology

A 42-year-old female presents with a destructive, lytic lesion in the proximal humerus with cortical breakthrough. Biopsy reveals malignant, pleomorphic spindle cells producing unmineralized osteoid. Which of the following is the most important prognostic factor for overall survival in a patient with this diagnosis without systemic metastasis on initial staging?

. Histological grade of the primary tumor
. Presence of macroscopic skip metastases
. Patient's age at the time of diagnosis
. Tumor necrosis response to neoadjuvant chemotherapy
. Anatomic location of the primary lesion

Correct Answer & Explanation

. Tumor necrosis response to neoadjuvant chemotherapy

Explanation

The clinical scenario describes high-grade osteosarcoma. In patients presenting with non-metastatic osteosarcoma, the histological response (percentage of tumor necrosis) to neoadjuvant chemotherapy is the single most important prognostic factor for long-term survival.

Question 2328

Topic: 10. Pathology and Oncology

A 48-year-old male presents with a palpable, painless mass on the dorsum of his wrist, which transilluminates. It is soft and slightly mobile. What is the most common diagnosis?

. Giant Cell Tumor of Tendon Sheath
. Epidermoid Cyst
. Ganglion Cyst
. Lipoma
. Soft Tissue Sarcoma

Correct Answer & Explanation

. Ganglion Cyst

Explanation

The description of a palpable, painless, transilluminating, soft, and slightly mobile mass on the dorsum of the wrist is classic for a dorsal wrist ganglion cyst. These are the most common soft tissue tumors of the hand and wrist, arising from joint capsules or tendon sheaths. Giant cell tumor of tendon sheath is typically solid and does not transilluminate. Epidermoid cysts can occur but are less common and may not transilluminate as clearly. Lipomas are rare in the wrist, and soft tissue sarcomas are exceedingly rare and typically have more concerning features.

Question 2329

Topic: 10. Pathology and Oncology

A patient presents with a painful, exquisitely tender, reddish-blue spot under the nail of her index finger that is sensitive to cold and light touch. What is the most likely diagnosis?

. Subungual hematoma
. Melanoma
. Glomus tumor
. Squamous cell carcinoma
. Wart

Correct Answer & Explanation

. Glomus tumor

Explanation

The classic triad of symptoms for a glomus tumor includes severe pain, cold sensitivity, and pin-point tenderness, often described as an 'electric shock.' It typically appears as a small, reddish-blue lesion under the nail. Subungual hematoma results from trauma. Melanoma and SCC are malignant lesions, often with different presentations. Warts are benign epithelial growths.

Question 2330

Topic: 10. Pathology and Oncology

A patient presents with a painful mass in the palm, distal to the carpal tunnel, which is confirmed to be a giant cell tumor of the tendon sheath. Which finger is most commonly affected by this benign tumor?

. Thumb
. Index finger
. Middle finger
. Ring finger
. Little finger

Correct Answer & Explanation

. Index finger

Explanation

Giant cell tumor of the tendon sheath (GCTTS), also known as pigmented villonodular synovitis (PVNS) in diffuse form, is the second most common soft tissue tumor of the hand after ganglion cysts. It most commonly affects the index finger, followed by the thumb. It typically presents as a firm, non-tender, slowly growing mass. Surgical excision is the treatment, but recurrence is possible.

Question 2331

Topic: 10. Pathology and Oncology

A biopsy from an adult patient with a lytic bone lesion shows numerous multinucleated giant cells, hemosiderin deposition, and mononuclear stromal cells. Radiographically, the lesion appears epiphyseal and expansile. Which diagnosis is most consistent with these findings?

. Aneurysmal bone cyst
. Giant cell tumor of bone
. Chondroblastoma
. Osteoblastoma
. Fibrous dysplasia

Correct Answer & Explanation

. Giant cell tumor of bone

Explanation

Giant cell tumor (GCT) of bone is a benign but locally aggressive tumor typically occurring in the epiphysis or metaphysis of long bones in skeletally mature individuals. Histologically, it is characterized by a uniform proliferation of neoplastic mononuclear stromal cells admixed with abundant osteoclast-like multinucleated giant cells. Hemorrhage and hemosiderin deposition are also common features. Aneurysmal bone cyst (ABC) can also have giant cells and hemorrhage but usually features blood-filled cystic spaces separated by fibrous septa and lacks the uniform neoplastic stromal cells of GCT. Chondroblastoma is epiphyseal but composed of chondroblasts. Osteoblastoma is typically metaphyseal/diaphyseal and composed of osteoblasts forming osteoid. Fibrous dysplasia is a fibro-osseous lesion with immature woven bone within a fibrous stroma.

Question 2332

Topic: 10. Pathology and Oncology

A bone biopsy from a 15-year-old male with leg pain reveals malignant spindle cells producing osteoid directly, without a cartilaginous intermediate. This histological finding is characteristic of which primary bone tumor?

. Chondrosarcoma
. Ewing sarcoma
. Osteosarcoma
. Fibrosarcoma of bone
. Giant cell tumor

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common primary malignant bone tumor in adolescents and young adults. The definitive histological diagnostic criterion for osteosarcoma is the direct production of osteoid (unmineralized bone matrix) or immature woven bone by the malignant tumor cells. Chondrosarcoma produces malignant cartilage matrix. Ewing sarcoma is characterized by small, round, blue cells. Fibrosarcoma produces collagen but not osteoid or cartilage. Giant cell tumor is benign and characterized by numerous multinucleated giant cells and mononuclear stromal cells.

Question 2333

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a destructive diaphyseal lesion in his femur with an "onion-skin" periosteal reaction. A biopsy is planned. Which specific chromosomal translocation is the diagnostic hallmark of this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic picture suggests Ewing sarcoma. The diagnostic hallmark of Ewing sarcoma is the t(11;22)(q24;q12) translocation, which results in the EWS-FLI1 fusion protein in about 85% of cases.

Question 2334

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a permeative lytic lesion in the diaphysis of the femur. Biopsy reveals small round blue cells. Cytogenetic analysis of the tumor is most likely to show which of the following chromosomal translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is classically characterized by the t(11;22) chromosomal translocation, which results in the EWS-FLI1 fusion protein. It typically presents as a permeative diaphyseal lesion in children and adolescents.

Question 2335

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a diaphyseal bone tumor. Biopsy reveals small round blue cells. Which specific chromosomal translocation is diagnostic for this malignancy?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation, creating the EWS-FLI1 fusion protein. This cytogenetic marker is highly specific and used for molecular diagnosis.

Question 2336

Topic: 10. Pathology and Oncology

A 30-year-old female presents with knee pain. Radiographs reveal an eccentric, purely lytic lesion in the distal femoral epiphysis extending to the subchondral bone. Biopsy shows mononuclear cells and multinucleated giant cells. The neoplastic cells express RANKL. What is the diagnosis?

. Aneurysmal bone cyst
. Chondroblastoma
. Giant Cell Tumor of bone
. Osteosarcoma
. Brown tumor of hyperparathyroidism

Correct Answer & Explanation

. Giant Cell Tumor of bone

Explanation

Giant cell tumors typically present as eccentric, lytic epiphyseal lesions in skeletally mature young adults. The neoplastic mononuclear stromal cells express RANKL, which recruits the reactive multinucleated osteoclast-like giant cells.

Question 2337

Topic: 10. Pathology and Oncology

A 15-year-old male is diagnosed with classic high-grade osteosarcoma of the distal femur. Upon initial staging, what is the single most important prognostic factor for long-term survival?

. Histologic subtype (e.g., osteoblastic vs. chondroblastic)
. Absolute tumor volume
. Presence of pulmonary metastases
. Baseline serum alkaline phosphatase level
. Anatomic location of the primary lesion

Correct Answer & Explanation

. Presence of pulmonary metastases

Explanation

The presence of detectable metastases (most commonly pulmonary) at the time of initial diagnosis is the most significant negative prognostic factor in osteosarcoma. Non-metastatic disease has a significantly higher 5-year survival rate.

Question 2338

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive night pain in his distal femur. Radiographs show a destructive metaphyseal lesion with a "sunburst" periosteal reaction and Codman's triangle. Histology reveals malignant spindle cells producing unmineralized osteoid. What is the most critical step in initial staging?

. Whole-body magnetic resonance imaging (MRI)
. High-resolution computed tomography (CT) of the chest
. Positron emission tomography (PET) scan
. Iliac crest bone marrow aspirate and biopsy
. Serial serum alkaline phosphatase level measurements

Correct Answer & Explanation

. High-resolution computed tomography (CT) of the chest

Explanation

The scenario describes classic osteosarcoma, which most commonly metastasizes hematogenously to the lungs. Therefore, a high-resolution CT scan of the chest is an essential and critical component of initial tumor staging.

Question 2339

Topic: 10. Pathology and Oncology

In the context of bone tumors, an examiner asks about the typical radiological appearance of a benign, slow-growing lesion. Which feature is most suggestive of a benign process?

. Permeative cortical destruction with a wide zone of transition.
. Presence of a 'sunburst' periosteal reaction.
. Aggressive soft tissue mass associated with cortical breach.
. Sclerotic margin and a narrow zone of transition.
. Codman's triangle formation.

Correct Answer & Explanation

. Sclerotic margin and a narrow zone of transition.

Explanation

A sclerotic margin (rim of reactive bone) and a narrow zone of transition (well-defined border between normal and abnormal bone) are classic radiological features indicating a slow-growing, benign lesion. Permeative cortical destruction with a wide zone of transition, a 'sunburst' periosteal reaction, aggressive soft tissue mass, and Codman's triangle are all features typically associated with aggressive, malignant bone lesions.

Question 2340

Topic: 10. Pathology and Oncology

Which factor is most influential in determining the prognosis and management strategy for a patient with metastatic bone disease?

. The exact anatomical location of the metastasis.
. The patient's age.
. The type and aggressiveness of the primary tumor.
. The presence of pathological fracture.
. The patient's socioeconomic status.

Correct Answer & Explanation

. The type and aggressiveness of the primary tumor.

Explanation

The type and aggressiveness of the primary tumor are most influential in determining the overall prognosis and guiding the management strategy for metastatic bone disease. Different primary tumors (e.g., breast, prostate, lung, renal, thyroid) have varying biological behaviors, growth rates, responsiveness to systemic therapies, and life expectancies, which directly impact the decision-making process for orthopedic interventions. While other factors like location, pathological fracture, and age are important for local management, the primary tumor dictates the overall oncological plan.

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