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10. Pathology and Oncology MCQs

Practice Set 121 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 2401

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in the diaphysis of his left femur. Radiographs show a permeative, destructive lesion with an 'onion-skin' periosteal reaction. A biopsy is performed. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. Ewing sarcoma is characterized by the t(11;22)(q24;q12) chromosomal translocation in approximately 85% of cases, which results in the fusion of the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11.

Question 2402

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with chronic right knee pain. Radiographs reveal an eccentric, heavily calcified, lytic lesion located purely within the epiphysis of the distal femur, surrounded by a thin sclerotic rim. Histological evaluation demonstrates mononuclear cells with longitudinal nuclear grooves and areas of fine, pericellular calcification resembling "chicken-wire." What is the most likely diagnosis?

. Giant cell tumor
. Chondroblastoma
. Clear cell chondrosarcoma
. Osteoblastoma
. Aneurysmal bone cyst

Correct Answer & Explanation

. Chondroblastoma

Explanation

The clinical presentation, radiographic location (epiphyseal), and distinct histology indicate a chondroblastoma. Chondroblastomas are benign, cartilage-producing bone tumors that classically arise in the epiphyses or apophyses of long bones in skeletally immature patients. The pathognomonic histological feature is the presence of "chicken-wire" calcification surrounding mononuclear cells that often have longitudinal nuclear grooves (coffee-bean nuclei). Giant cell tumors can also be epiphyseal but typically occur after growth plate closure and lack the characteristic chicken-wire calcification.

Question 2403

Topic: 10. Pathology and Oncology

A 25-year-old male presents with chronic dull anterior shin pain. Radiographs show a bubbly, multi-loculated lytic lesion in the anterior diaphysis of the tibia. Biopsy demonstrates islands of epithelial cells arrayed in a palisading pattern within a benign-appearing fibrous stroma. What is the most likely diagnosis and appropriate definitive treatment?

. Osteofibrous dysplasia - observation
. Adamantinoma - wide surgical resection
. Chondromyxoid fibroma - curettage and bone grafting
. Ewing sarcoma - neoadjuvant chemotherapy and wide resection
. Eosinophilic granuloma - intralesional corticosteroid injection

Correct Answer & Explanation

. Adamantinoma - wide surgical resection

Explanation

The diagnosis is adamantinoma. It is a rare, low-grade malignant bone tumor that almost exclusively occurs in the anterior diaphysis of the tibia. The pathognomonic histology is biphasic, showing islands or nests of epithelial cells (which stain positive for cytokeratin) surrounded by a fibrous stroma. Because it is a low-grade malignancy that does not respond well to radiation or chemotherapy, the standard of care is wide surgical resection. Osteofibrous dysplasia occurs in the same location but typically in children <10 years and lacks the malignant epithelial nests.

Question 2404

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic knee pain. Radiographs reveal an epiphyseal lytic lesion in the proximal tibia with internal calcifications. Biopsy shows lobules of cells with abundant clear cytoplasm, distinct borders, and scattered giant cells. Which of the following is the most appropriate definitive management?

. Radiofrequency ablation
. Curettage and bone grafting
. Wide surgical resection
. Neoadjuvant chemotherapy followed by wide resection
. Primary radiation therapy

Correct Answer & Explanation

. Wide surgical resection

Explanation

The clinical and histologic picture describes clear cell chondrosarcoma, a low-grade malignant bone tumor that classically occurs in the epiphysis of long bones in adults (unlike chondroblastoma which is epiphyseal but occurs in skeletally immature patients). The treatment of choice is wide surgical resection, as it is relatively radio- and chemo-resistant and prone to local recurrence if managed with intralesional curettage.

Question 2405

Topic: 10. Pathology and Oncology

A 16-year-old male presents with a permeative lytic lesion in the diaphysis of the femur associated with a lamellated 'onion-skin' periosteal reaction. Biopsy demonstrates uniform sheets of small round blue cells. Cytogenetic analysis is most likely to reveal which of the following translocations?

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

Correct Answer & Explanation

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

Explanation

The clinical and histological findings describe Ewing sarcoma. The most common chromosomal abnormality in Ewing sarcoma is the balanced translocation t(11;22)(q24;q12), occurring in roughly 85% of cases. This results in the fusion of the EWS gene on chromosome 22 to the FLI1 gene on chromosome 11. t(X;18) is associated with synovial sarcoma; t(12;16) with myxoid liposarcoma; t(2;13) with alveolar rhabdomyosarcoma.

Question 2406

Topic: 10. Pathology and Oncology
Following administration of neoadjuvant chemotherapy, a 15-year-old patient undergoes wide surgical resection for conventional high-grade osteosarcoma of the distal femur. According to the Huvos grading system, what is the minimum percentage of tumor necrosis required to classify the tumor as having a 'good histologic response'?
. Greater than 50%
. Greater than 75%
. Greater than 90%
. Greater than 95%
. Greater than 99%

Correct Answer & Explanation

. Greater than 90%

Explanation

The histologic response to neoadjuvant chemotherapy in osteosarcoma is the most important prognostic factor. A 'good responder' is defined by the Huvos criteria as having 90% or greater tumor necrosis (Grade III is 90-99% necrosis; Grade IV is 100% necrosis). Patients with <90% necrosis are considered poor responders.

Question 2407

Topic: 10. Pathology and Oncology

A 15-year-old female presents with distal femur pain. Imaging reveals a mixed lytic/sclerotic metaphyseal lesion with periosteal reaction. Biopsy confirms high-grade osteosarcoma. Which of the following histologic subtypes has the worst overall prognosis?

. Osteoblastic
. Chondroblastic
. Fibroblastic
. Telangiectatic
. Small cell

Correct Answer & Explanation

. Small cell

Explanation

Small cell osteosarcoma is a rare variant that typically has a worse prognosis than the conventional subtypes (osteoblastic, chondroblastic, fibroblastic) or telangiectatic osteosarcoma. It is often confused histologically with Ewing sarcoma but produces osteoid. Telangiectatic osteosarcoma has a similar or slightly better prognosis compared to conventional osteosarcoma when treated with modern chemotherapy protocols.

Question 2408

Topic: 10. Pathology and Oncology

In a 15-year-old patient diagnosed with high-grade, non-metastatic conventional osteosarcoma of the distal femur, which of the following is considered the single most important prognostic factor for long-term overall survival?

. Age of the patient at the time of diagnosis
. Maximum cross-sectional diameter of the tumor
. The specific histologic subtype (e.g., osteoblastic vs. chondroblastic)
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. The use of an expandable endoprosthesis for reconstruction

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The degree of histologic tumor necrosis following preoperative (neoadjuvant) chemotherapy is the most reliable and powerful prognostic indicator in high-grade osteosarcoma. A 'good response' is classically defined as 90% or greater tumor necrosis, which strongly correlates with improved disease-free and overall survival rates.

Question 2409

Topic: 10. Pathology and Oncology

A 16-year-old male presents with severe right thigh pain that is distinctly worse at night and dramatically relieved by ibuprofen. Imaging reveals a 1.0 cm radiolucent nidus surrounded by dense reactive sclerosis in the proximal femoral diaphysis. The pathogenesis of this lesion's characteristic pain profile is primarily mediated by local overexpression of which substance?

. Tumor necrosis factor-alpha
. Prostaglandin E2
. Interleukin-6
. Fibroblast growth factor-23
. Bone morphogenetic protein-2

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteoma is a benign bone-forming tumor characterized by a small radiolucent nidus (<1.5 cm) surrounded by dense sclerotic bone. The intense, night-time pain that is classically relieved by NSAIDs is due to the extremely high production of Prostaglandin E2 (PGE2) by the nidus-forming osteoblasts. The nidus contains up to 1000 times the normal level of PGE2.

Question 2410

Topic: 10. Pathology and Oncology

A 12-year-old girl presents with a destructive diaphyseal lesion in the right fibula, accompanied by an 'onion-skin' periosteal reaction. A core needle biopsy reveals a small blue round cell tumor. Molecular genetic testing identifies a t(11;22)(q24;q12) chromosomal translocation. Immunohistochemistry of this tumor is most likely to show strong, diffuse membrane positivity for which of the following markers?

. Desmin
. MyoD1
. CD99 (MIC2)
. Cytokeratin
. S-100

Correct Answer & Explanation

. CD99 (MIC2)

Explanation

The clinical, radiographic, and genetic findings (t(11;22) producing the EWS-FLI1 fusion protein) are diagnostic of Ewing Sarcoma. Ewing sarcoma cells characteristically show strong, diffuse membranous staining for CD99 (the product of the MIC2 gene). Desmin and MyoD1 are positive in rhabdomyosarcoma. S-100 is positive in neural crest origin tumors (like melanoma or schwannoma) and some cartilage tumors. Cytokeratin is a marker for carcinomas and synovial sarcoma.

Question 2411

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain. Radiographs show a destructive, bone-forming lesion in the distal femur metaphysis with a 'sunburst' periosteal reaction. A biopsy confirms high-grade conventional osteosarcoma. What is the standard treatment protocol?

. Wide surgical resection alone
. Neoadjuvant chemotherapy followed by wide surgical resection and adjuvant chemotherapy
. Radiation therapy followed by surgical resection
. Primary amputation without chemotherapy
. Intralesional curettage and bone grafting

Correct Answer & Explanation

. Neoadjuvant chemotherapy followed by wide surgical resection and adjuvant chemotherapy

Explanation

The standard of care for high-grade, conventional osteosarcoma is neoadjuvant (pre-operative) multi-agent chemotherapy, followed by wide surgical resection (limb-salvage when possible), and then adjuvant (post-operative) chemotherapy tailored by the percentage of histologic necrosis in the resected specimen.

Question 2412

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with worsening distal thigh pain. Radiographs show a destructive, permeative metaphyseal lesion with a 'sunburst' periosteal reaction and a Codman's triangle. Core needle biopsy confirms high-grade conventional osteosarcoma. What is the current standard treatment protocol?

. Immediate above-knee amputation followed by radiation therapy
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Neoadjuvant radiation therapy followed by wide limb-sparing resection
. Wide surgical resection followed by definitive radiation therapy
. Primary radiation therapy combined with targeted immunotherapy

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

The standard of care for high-grade conventional osteosarcoma is neoadjuvant (preoperative) chemotherapy, followed by wide surgical resection (limb salvage is preferred when feasible), and subsequently adjuvant (postoperative) chemotherapy. Osteosarcoma is generally considered radioresistant, so radiation therapy is primarily reserved for unresectable tumors or positive margins.

Question 2413

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a slow-growing, painful soft tissue mass on the plantar aspect of his foot. Biopsy reveals a biphasic tumor containing both epithelial and spindle cell components. Which of the following chromosomal translocations is characteristic of this pathology?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The patient has a synovial sarcoma, which frequently presents in the extremities of young adults and can be biphasic (epithelial and spindle cells). It is genetically characterized by the t(X;18)(p11;q11) translocation, resulting in the SYT-SSX fusion gene. t(11;22) is found in Ewing sarcoma, t(12;16) in myxoid liposarcoma, and t(2;13) in alveolar rhabdomyosarcoma.

Question 2414

Topic: Bone Tumors

When differentiating an osteoblastoma from an osteoid osteoma based on histological and clinical features, which of the following characteristics is definitive for an osteoblastoma?

. Location primarily in the diaphysis of long bones
. Dramatic and complete relief of pain with NSAIDs
. Size greater than 2 cm in diameter
. Presence of a thick reactive sclerotic rim
. A characteristic radiolucent nidus measuring less than 1 cm

Correct Answer & Explanation

. Size greater than 2 cm in diameter

Explanation

Osteoid osteoma and osteoblastoma are histologically very similar (both contain interlacing trabeculae of osteoid surrounded by osteoblasts). The primary differentiating factor is size: osteoblastomas are defined as being greater than 2 cm in diameter, while osteoid osteomas are less than 2 cm (often <1 cm). Additionally, osteoblastomas tend to occur in the posterior elements of the spine, are less likely to have a thick sclerotic reactive rim, and the pain is typically progressive and less dramatically responsive to NSAIDs compared to osteoid osteoma.

Question 2415

Topic: 10. Pathology and Oncology

A 28-year-old female undergoes a wide local excision of a slow-growing soft tissue mass adjacent to her knee joint. Histopathology reveals a biphasic tumor with both epithelial and spindle cell components. Molecular testing confirms the diagnosis of synovial sarcoma. Which of the following chromosomal translocations is the hallmark of this specific malignancy?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, which fuses the SYT gene on chromosome 18 with one of the SSX genes (SSX1, SSX2, or SSX4) on the X chromosome. t(11;22) is characteristic of Ewing sarcoma. t(12;16) is found in myxoid liposarcoma. t(2;13) is classic for alveolar rhabdomyosarcoma. t(9;22) is the Philadelphia chromosome seen in chronic myeloid leukemia (and some acute leukemias).

Question 2416

Topic: 10. Pathology and Oncology

A 65-year-old male presents with a pathologic fracture of the proximal humerus. Workup reveals hypercalcemia, renal insufficiency, normocytic anemia, and a monoclonal protein spike on serum electrophoresis. Histological examination of the fracture site is most likely to show which of the following?

. Small round blue cells with positive CD99 staining
. Atypical spindle cells producing malignant osteoid
. Sheets of atypical plasma cells with eccentric nuclei and clock-face chromatin
. Multinucleated giant cells in a background of mononuclear stromal cells
. Nests of epithelial cells with positive cytokeratin staining

Correct Answer & Explanation

. Sheets of atypical plasma cells with eccentric nuclei and clock-face chromatin

Explanation

The clinical presentation (CRAB criteria: hyperCalcemia, Renal insufficiency, Anemia, Bone lesions) and monoclonal gammopathy are classic for Multiple Myeloma. Histologically, multiple myeloma is characterized by sheets of atypical, neoplastic plasma cells, which characteristically possess eccentric nuclei and a 'clock-face' chromatin pattern.

Question 2417

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a painful mass in the diaphysis of the left femur. Radiographs show a permeative, destructive lesion with an 'onion-skin' periosteal reaction. A core needle biopsy is performed. Which of the following chromosomal translocations is most pathognomonic for this tumor?

. 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

The clinical and radiographic picture describes Ewing's sarcoma. The pathognomonic chromosomal translocation for Ewing's sarcoma is t(11;22)(q24;q12), which results 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; and t(2;13) in alveolar rhabdomyosarcoma.

Question 2418

Topic: 10. Pathology and Oncology
In the modern treatment protocol for high-grade, non-metastatic intramedullary osteosarcoma, surgical resection is typically preceded by neoadjuvant chemotherapy. Following surgical resection, which of the following histological parameters is the most important prognostic factor for the patient's long-term overall survival?
. The histological subtype (osteoblastic vs. chondroblastic)
. The exact anatomic location of the tumor
. The percentage of tumor necrosis induced by chemotherapy
. The mitotic index of the residual tumor cells
. The presence of skip metastases on MRI

Correct Answer & Explanation

. The percentage of tumor necrosis induced by chemotherapy

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy (graded by the Huvos system) is the single most important prognostic indicator for overall survival in patients with non-metastatic high-grade osteosarcoma. A necrosis rate of >90% (Huvos grade III or IV) defines a 'good responder' and correlates strongly with improved survival.

Question 2419

Topic: Bone Tumors

A 15-year-old male presents with painful thoracolumbar scoliosis. Imaging reveals a 7 mm radiolucent nidus with surrounding sclerosis in the pedicle of T11 on the concave side of the curve. The lesion is situated 2 mm from the traversing nerve root. What is the most appropriate definitive management?

. Radiofrequency ablation (RFA)
. Prolonged immobilization in a TLSO brace
. Percutaneous cryoablation
. En bloc spondylectomy
. Surgical curettage and/or excision

Correct Answer & Explanation

. Surgical curettage and/or excision

Explanation

The diagnosis is an osteoid osteoma causing painful secondary scoliosis. While radiofrequency ablation (RFA) is the standard of care for most appendicular osteoid osteomas, it is relatively contraindicated for spinal lesions located within 1 cm of neural elements due to the high risk of thermal nerve injury. In such cases, open or minimally invasive surgical curettage/excision is preferred.

Question 2420

Topic: 10. Pathology and Oncology

A 12-year-old girl presents with deep, achy leg pain. Radiographs demonstrate a permeative, lytic lesion in the diaphysis of the femur with an 'onion skin' periosteal reaction. Biopsy confirms Ewing sarcoma. Which of the following chromosomal translocations is the genetic hallmark of this malignancy?

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

Correct Answer & Explanation

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

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation in about 85-90% of cases, resulting in the EWS-FLI1 fusion gene. t(X;18) is associated with synovial sarcoma; t(9;22) is the Philadelphia chromosome seen in CML; t(2;13) is seen in alveolar rhabdomyosarcoma; and t(12;16) is characteristic of myxoid liposarcoma.

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