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10. Pathology and Oncology MCQs

Practice Set 291 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 5801

Topic: Bone Tumors

A 68-year-old man presents with severe back pain. Plain radiographs reveal multiple "punched-out" lytic lesions in his skull and spine. If a technetium-99m bone scan is performed, what is the most likely expected finding for these specific lesions?

. Intensely hot spots due to reactive bone formation
. Cold spots (false-negative) due to absent osteoblastic activity
. Symmetrical radiotracer uptake in the appendicular skeleton
. A diffuse super-scan appearance
. Tram-track peripheral uptake

Correct Answer & Explanation

. Cold spots (false-negative) due to absent osteoblastic activity

Explanation

Multiple myeloma causes bone destruction via intense, pure osteoclast activation with little to no reactive osteoblastic response. Because a technetium-99m bone scan relies on osteoblastic activity (bone formation), myeloma lesions typically appear as "cold" or false-negative spots.

Question 5802

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a painful mass around his distal femur. Radiographs show a sunburst periosteal reaction and Codman's triangle. What is the most significant prognostic factor for survival in this patient?

. Initial tumor volume
. Histologic subtype of the tumor
. Extent of tumor necrosis following neoadjuvant chemotherapy
. The presence of a pathologic fracture at presentation
. The patient's age and gender

Correct Answer & Explanation

. Extent of tumor necrosis following neoadjuvant chemotherapy

Explanation

In osteosarcoma, the degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor. Greater than 90% necrosis indicates a good response and correlates with improved long-term survival.

Question 5803

Topic: 10. Pathology and Oncology

A 30-year-old female presents with knee pain and a lytic epiphyseal lesion extending to the articular surface of the proximal tibia. Biopsy reveals multinucleated giant cells in a background of mononuclear stromal cells. Which cell type is the true neoplastic component of this tumor?

. The multinucleated giant cells
. The mononuclear stromal cells
. Osteoblasts within the reactive rim
. Chondrocytes in the subchondral bone
. Macrophages scattered in the matrix

Correct Answer & Explanation

. The mononuclear stromal cells

Explanation

In a giant cell tumor of bone, the spindle-shaped mononuclear stromal cells are the actual neoplastic cells. These stromal cells express RANKL, which recruits and stimulates the formation of the reactive, non-neoplastic multinucleated giant cells responsible for the osteolysis.

Question 5804

Topic: 10. Pathology and Oncology

Which of the following genetic alterations is most classically associated with the development of conventional osteosarcoma?

. t(11;22) translocation
. Mutation in the EXT1 gene
. Mutation in the p53 and Rb tumor suppressor genes
. t(X;18) translocation
. Amplification of the MDM2 gene

Correct Answer & Explanation

. Mutation in the p53 and Rb tumor suppressor genes

Explanation

Conventional osteosarcoma is highly associated with mutations in the retinoblastoma (Rb) and p53 tumor suppressor genes. Patients with Li-Fraumeni syndrome (p53) and hereditary retinoblastoma both have a significantly increased risk of developing osteosarcoma.

Question 5805

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a permeative lytic lesion in the diaphysis of the femur with an 'onion skin' periosteal reaction. Biopsy confirms Ewing sarcoma. Which of the following is the most common chromosomal translocation associated with this diagnosis?

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

Correct Answer & Explanation

. t(11;22)(q24;q12)

Explanation

Ewing sarcoma is classically associated with the t(11;22)(q24;q12) translocation, resulting in the EWS-FLI1 fusion protein. t(X;18) is seen in synovial sarcoma; t(12;16) in myxoid liposarcoma; t(9;22) in CML (Philadelphia chromosome); t(2;13) in alveolar rhabdomyosarcoma.

Question 5806

Topic: 10. Pathology and Oncology

A 60-year-old male presents with a destructive diaphyseal lesion in his humerus. Biopsy reveals sheets of plasma cells with eccentric nuclei and 'clock-face' chromatin. Which of the following lab findings is most consistently associated with his primary diagnosis?

. Elevated alkaline phosphatase
. Elevated prostate-specific antigen
. Monoclonal spike on serum protein electrophoresis (SPEP)
. Positive tartrate-resistant acid phosphatase (TRAP)
. t(11;22) translocation

Correct Answer & Explanation

. Monoclonal spike on serum protein electrophoresis (SPEP)

Explanation

This patient has multiple myeloma, the most common primary bone malignancy in adults. Diagnosis relies on identifying a monoclonal gammopathy (M-spike) on SPEP or UPEP, along with a bone marrow biopsy confirming clonal plasma cells.

Question 5807

Topic: 10. Pathology and Oncology

Which of the following chromosomal translocations is most characteristic of Ewing sarcoma?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is classically associated with the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein. This mutation acts as an aberrant transcription factor promoting oncogenesis.

Question 5808

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a pathologic fracture through a central, purely lytic lesion in the proximal humerus. Radiographs reveal the "fallen leaf" sign. What is the most likely composition of the fluid inside this lesion prior to the fracture?

. Blood
. Serous fluid with high osteoclast concentration
. Clear or straw-colored fluid
. Purulent exudate
. Viscous mucin

Correct Answer & Explanation

. Clear or straw-colored fluid

Explanation

The clinical presentation and "fallen leaf" sign on radiographs are pathognomonic for a Unicameral Bone Cyst (UBC). Prior to a fracture, these benign cysts are typically filled with a clear or straw-colored serous fluid.

Question 5809

Topic: 10. Pathology and Oncology

A 60-year-old male presents with a pathologic proximal humerus fracture secondary to metastatic renal cell carcinoma. Preoperative planning for open reduction and internal fixation should strongly include which of the following?

. Preoperative radiation therapy
. Preoperative systemic chemotherapy
. Preoperative selective arterial embolization
. Neoadjuvant bisphosphonate infusion
. Immediate amputation

Correct Answer & Explanation

. Preoperative selective arterial embolization

Explanation

Metastases from renal cell carcinoma and thyroid carcinoma are highly vascular. Preoperative selective arterial embolization 24 to 48 hours prior to surgery significantly reduces massive intraoperative blood loss.

Question 5810

Topic: 10. Pathology and Oncology

Ewing sarcoma is a highly aggressive bone tumor classically associated with which of the following chromosomal translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation in over 85% of cases, leading to the formation of the EWS-FLI1 fusion protein. Synovial sarcoma is associated with t(X;18).

Question 5811

Topic: 10. Pathology and Oncology

A 16-year-old boy presents with severe right thigh pain that is worse at night and dramatically relieved by NSAIDs. Imaging reveals a 1 cm radiolucent nidus with surrounding reactive sclerosis in the femoral diaphysis. What is the characteristic histological finding of the nidus?

. Malignant spindle cells producing lace-like immature osteoid
. Interlacing woven bone trabeculae lined by osteoblasts without atypia
. Cartilage-capped bony exostosis extending from the metaphysis
. Sheets of uniform small round blue cells with positive CD99 staining
. Multinucleated giant cells evenly dispersed in a background of mononuclear stromal cells

Correct Answer & Explanation

. Interlacing woven bone trabeculae lined by osteoblasts without atypia

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. Histologically, the nidus consists of a complex, interlacing network of woven bone trabeculae (osteoid) lined by prominent, yet entirely benign, osteoblasts, set within a highly vascularized fibrovascular connective tissue stroma.

Question 5812

Topic: 10. Pathology and Oncology
According to the Enneking surgical staging system for musculoskeletal tumors, a high-grade osteosarcoma that has broken through the bone cortex into the surrounding soft tissue without distant metastases is classified as:
. Stage IA
. Stage IB
. Stage IIA
. Stage IIB
. Stage III

Correct Answer & Explanation

. Stage IIB

Explanation

In the Enneking staging system, Stage II indicates a high-grade tumor. The "B" designation signifies that the lesion is extracompartmental, meaning it has extended outside its compartment of origin.

Question 5813

Topic: 10. Pathology and Oncology

Molecular analysis of a suspected bone tumor reveals the specific chromosomal translocation t(11;22), resulting in the EWS-FLI1 fusion gene. Which of the following is the most likely diagnosis?

. Synovial sarcoma
. Osteosarcoma
. Ewing sarcoma
. Clear cell chondrosarcoma
. Myxoid liposarcoma

Correct Answer & Explanation

. Ewing sarcoma

Explanation

Ewing sarcoma is classically characterized by the t(11;22) chromosomal translocation. This creates the EWS-FLI1 fusion protein, which acts as an aberrant transcription factor driving oncogenesis.

Question 5814

Topic: 10. Pathology and Oncology

The Mirels criteria are used to assess the risk of a pathological fracture in a long bone affected by a metastatic lesion. Which of the following is NOT one of the four parameters evaluated in the Mirels scoring system?

. Site of the lesion (Upper extremity vs Lower extremity vs Peritrochanteric)
. Nature of the lesion (Blastic vs Mixed vs Lytic)
. Size of the lesion relative to bone diameter
. Degree of pain (Mild vs Moderate vs Functional)
. Primary tumor histology (e.g., breast, prostate, lung)

Correct Answer & Explanation

. Primary tumor histology (e.g., breast, prostate, lung)

Explanation

The Mirels scoring system uses four parameters to predict pathological fracture risk: Site (upper limb, lower limb, peritrochanteric), Pain (mild, moderate, functional), Lesion nature (blastic, mixed, lytic), and Size (<1/3, 1/3-2/3, >2/3 of cortical diameter). Primary tumor histology is not one of the criteria scored.

Question 5815

Topic: 10. Pathology and Oncology

An 18-year-old male presents with deep knee pain and a mixed lytic/sclerotic lesion in the distal femur. Biopsy confirms high-grade intramedullary osteosarcoma. What is the standard treatment algorithm?

. Primary amputation followed by radiation
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Wide surgical resection alone
. Radiation therapy followed by wide surgical resection
. Neoadjuvant radiation, surgical resection, and adjuvant radiation

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

High-grade osteosarcoma is typically treated with neoadjuvant chemotherapy, followed by surgical resection with wide margins, and then adjuvant chemotherapy to address systemic micrometastases.

Question 5816

Topic: Bone Tumors

A 60-year-old female with back pain has punched-out lytic skull lesions and a monoclonal protein spike. What is the most appropriate imaging modality to evaluate the extent of her skeletal involvement?

. Technetium-99m bone scan
. Low-dose whole-body CT or skeletal survey
. MRI of the cervical spine only
. Dual-energy X-ray absorptiometry (DEXA)
. Diagnostic ultrasound

Correct Answer & Explanation

. Low-dose whole-body CT or skeletal survey

Explanation

Multiple myeloma lesions are purely lytic and lack reactive osteoblastic activity. Therefore, a Technetium-99m bone scan is often falsely negative; a low-dose whole-body CT or skeletal survey is the standard.

Question 5817

Topic: Bone Tumors

A 15-year-old boy presents with aching knee pain that is noticeably worse at night and dramatically relieved by ibuprofen. Radiographs show a small radiolucent nidus with surrounding sclerosis in the proximal tibia. What is the primary molecular driver of his pain?

. Mechanical instability causing periosteal stretch
. High local production of Prostaglandin E2 by the nidus
. Microfractures within the surrounding sclerotic bone
. Direct neural compression by tumor expansion
. Histamine release from infiltrating mast cells

Correct Answer & Explanation

. High local production of Prostaglandin E2 by the nidus

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. The osteoblastic cells within the nidus produce extremely high levels of prostaglandins (particularly PGE2), mediating the characteristic night pain that responds to NSAIDs.

Question 5818

Topic: 10. Pathology and Oncology

A 60-year-old man presents with a destructive sacral mass causing bowel and bladder dysfunction. Biopsy reveals cells arranged in cords with abundant bubbly cytoplasm and distinct physaliferous features. What is the most likely diagnosis?

. Chondrosarcoma
. Chordoma
. Multiple Myeloma
. Giant Cell Tumor
. Metastatic Renal Cell Carcinoma

Correct Answer & Explanation

. Chordoma

Explanation

Chordomas are rare, low-grade malignant bone tumors arising from embryonic remnants of the notochord, most commonly located in the sacrococcygeal and spheno-occipital regions. The presence of large, vacuolated "physaliferous" cells is the pathognomonic histologic hallmark.

Question 5819

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in his distal femur. Biopsy reveals a small round blue cell tumor. Molecular testing is positive for a t(11;22) translocation. What is the most likely diagnosis and its associated fusion gene?

. Osteosarcoma (RB1)
. Ewing sarcoma (EWS-FLI1)
. Synovial sarcoma (SYT-SSX1)
. Rhabdomyosarcoma (PAX3-FOXO1)
. Chondrosarcoma (EXT1)

Correct Answer & Explanation

. Ewing sarcoma (EWS-FLI1)

Explanation

Ewing sarcoma is classically characterized by the t(11;22) chromosomal translocation, which results in the EWS-FLI1 fusion gene. It typically presents as a small round blue cell tumor in children and young adults.

Question 5820

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with progressive diaphyseal leg pain. Radiographs reveal a permeative lytic lesion in the tibial diaphysis with an "onion skin" periosteal reaction. Cytogenetic analysis is most likely to reveal which of the following translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. This tumor is strongly associated with the t(11;22) chromosomal translocation, which results in the EWS-FLI1 fusion protein.

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