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10. Pathology and Oncology MCQs

Practice Set 97 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 1921

Topic: 10. Pathology and Oncology

A 28-year-old male presents with chronic anterior tibial pain. Radiographs demonstrate a multilocular, expansile, eccentric osteolytic lesion in the anterior cortex of the tibial diaphysis. Histological analysis reveals nests of epithelial cells in a fibrous stroma. What is the most appropriate definitive management?

. Intralesional curettage, adjuvant phenol, and bone grafting
. Neoadjuvant systemic chemotherapy followed by intralesional curettage
. Wide en bloc surgical resection
. External beam radiation therapy alone
. Percutaneous radiofrequency ablation

Correct Answer & Explanation

. Wide en bloc surgical resection

Explanation

The clinical, radiographic, and histological presentation is characteristic of an adamantinoma. It is a low-grade, slow-growing malignant bone tumor most commonly found in the anterior cortex of the tibial diaphysis. Because it is highly resistant to both chemotherapy and radiation therapy, and has an unacceptably high local recurrence rate following intralesional procedures, the standard of care is wide en bloc resection.

Question 1922

Topic: 10. Pathology and Oncology

An oncologist consults you regarding prophylactic fixation of a metastatic bone lesion in a 60-year-old female with breast cancer. According to Mirels' criteria, which of the following clinical scenarios yields a strict score of 9, strongly indicating the need for prophylactic fixation?

. Blastic lesion in the upper extremity, <1/3 cortical width, moderate pain
. Mixed lesion in the lower extremity, 1/3 to 2/3 cortical width, mild pain
. Lytic lesion in the peritrochanteric region, >2/3 cortical width, mild pain
. Lytic lesion in the upper extremity, 1/3 to 2/3 cortical width, severe pain
. Blastic lesion in the peritrochanteric region, <1/3 cortical width, severe pain

Correct Answer & Explanation

. Lytic lesion in the upper extremity, 1/3 to 2/3 cortical width, severe pain

Explanation

Mirels' scoring system evaluates 4 categories (Site, Pain, Lesion Nature, Size), assigning 1 to 3 points each. Option 3: Site (Upper extremity = 1) + Lesion Nature (Lytic = 3) + Size (1/3 to 2/3 = 2) + Pain (Severe = 3). Total = 1 + 3 + 2 + 3 = 9. A score of 9 or greater carries a high risk of impending fracture (>15%), making it a strong indication for prophylactic fixation.

Question 1923

Topic: 10. Pathology and Oncology

A 25-year-old female presents with a slow-growing, painful mass near her knee joint. MRI shows a soft tissue mass abutting the joint capsule, and plain films demonstrate punctate calcifications. Biopsy confirms a biphasic tumor with both epithelial and spindle cell components. Which chromosomal translocation is the hallmark of this malignancy?

. 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 is classic for synovial sarcoma. The hallmark cytogenetic abnormality is the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene. It often presents in young adults as a slow-growing juxta-articular mass with calcifications seen on radiographs in ~30% of cases. Despite the name, it rarely involves the synovial tissue directly but rather arises in adjacent soft tissues.

Question 1924

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with right knee pain. Radiographs reveal an eccentric, lytic lesion strictly confined to the distal femoral epiphysis with a thin sclerotic rim. Histological examination reveals mononuclear cells with grooved nuclei and areas of fine, pericellular calcifications. What is the most likely diagnosis?

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

Correct Answer & Explanation

. Chondroblastoma

Explanation

Chondroblastoma is a rare, benign bone tumor that characteristically arises in the epiphysis or apophysis of skeletally immature patients. Histologically, it is uniquely defined by chondroblasts with grooved or indented nuclei (often described as 'coffee bean' nuclei), intermixed multinucleated giant cells, and distinctive pericellular calcifications known as 'chicken-wire' calcifications.

Question 1925

Topic: 10. Pathology and Oncology

A 40-year-old female presents with recurrent, painful swelling of her knee. MRI demonstrates extensive synovial hypertrophy with nodular masses displaying low signal intensity on T1 and T2 sequences, and prominent 'blooming' artifact on gradient-echo sequences. Genetic testing reveals a translocation involving the colony-stimulating factor 1 (CSF1) gene. For severe, refractory cases, which targeted systemic therapy is FDA-approved?

. Denosumab
. Imatinib
. Pexidartinib
. Bevacizumab
. Rituximab

Correct Answer & Explanation

. Pexidartinib

Explanation

The clinical and MRI findings (hemosiderin blooming artifact) are diagnostic for diffuse tenosynovial giant cell tumor (TGCT), historically known as pigmented villonodular synovitis (PVNS). The pathogenesis relies on a t(1;2) translocation causing overexpression of CSF1. Pexidartinib is an orally administered tyrosine kinase inhibitor targeting the CSF1 receptor. It is the first FDA-approved systemic therapy for symptomatic, severe TGCT not amenable to surgical improvement.

Question 1926

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic knee pain. Radiographs reveal a secondary, eccentrically located, lytic lesion in the proximal tibial epiphysis. Biopsy reveals cells with distinct borders, abundant clear cytoplasm, and central nuclei, interspersed with areas of bland chondroid matrix. The lesion is graded as a low-grade malignancy. What is the most likely diagnosis?

. Chondroblastoma
. Clear cell chondrosarcoma
. Giant cell tumor of bone
. Osteoblastoma
. Enchondroma

Correct Answer & Explanation

. Clear cell chondrosarcoma

Explanation

Clear cell chondrosarcoma is a rare, low-grade malignant cartilage tumor that classically occurs in the epiphysis of long bones in adults (3rd-4th decades). While chondroblastoma also occurs in the epiphysis, it typically affects younger patients (open physes) and features 'coffee bean' nuclei with 'chicken-wire' calcifications, lacking the distinctive clear cytoplasm seen in clear cell chondrosarcoma.

Question 1927

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful, swollen thigh. Imaging demonstrates a permeative diaphyseal lesion of the femur with a prominent 'onion-skin' periosteal reaction. Biopsy reveals sheets of uniform small round blue cells that are strongly CD99 positive. Which specific chromosomal translocation is the diagnostic hallmark of this condition?

. 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 patient has Ewing sarcoma, characterized by CD99 (MIC2) positivity and a classic t(11;22) (q24;q12) translocation. This translocation fuses the EWSR1 gene on chromosome 22 with the FLI1 gene on chromosome 11. t(X;18) is seen in synovial sarcoma, t(12;16) in myxoid liposarcoma, and t(2;13) in alveolar rhabdomyosarcoma.

Question 1928

Topic: 10. Pathology and Oncology

A 25-year-old male presents with anterior bowing of his tibia and insidious onset of pain. Radiographs demonstrate an eccentric, multilobulated osteolytic lesion in the anterior diaphyseal cortex of the tibia. Histologic analysis reveals epithelial-like cells arranged in nests surrounded by a bland spindle-cell osteofibrous stroma. Immunohistochemistry is strongly positive for cytokeratin. Which of the following is the standard of care?

. Intralesional curettage and bone grafting
. Wide surgical resection and bone reconstruction
. Primary radiation therapy
. Neoadjuvant chemotherapy followed by marginal excision
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection and bone reconstruction

Explanation

The diagnosis is Adamantinoma, a rare, low-grade malignant bone tumor that almost exclusively occurs in the anterior tibial diaphysis. It is characterized pathologically by biphasic histology (epithelial nests positive for cytokeratin in a fibrous stroma). Adamantinoma is largely chemo- and radioresistant and has a high local recurrence rate if treated with curettage; thus, wide en bloc resection is the definitive treatment.

Question 1929

Topic: 10. Pathology and Oncology

Which of the following bone tumors typically presents as a densely ossified mass on the posterior surface of the distal femur in young adults, is histologically characterized by low-grade spindle cells interspersed with well-formed woven bone trabeculae, and frequently demonstrates MDM2 and CDK4 gene amplification?

. Periosteal osteosarcoma
. High-grade surface osteosarcoma
. Parosteal osteosarcoma
. Bizarre parosteal osteochondromatous proliferation (Nora's lesion)
. Osteochondroma

Correct Answer & Explanation

. Parosteal osteosarcoma

Explanation

Parosteal osteosarcoma is a low-grade surface osteosarcoma that classically arises on the posterior aspect of the distal femur. It is characterized pathologically by low-grade spindle cells and heavily ossified woven bone. Molecularly, it is distinguished by the amplification of MDM2 and CDK4 on chromosome 12q13-15.

Question 1930

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slowly enlarging, deep soft tissue mass in the popliteal fossa, not directly involving the joint. Radiographs show stippled calcifications within the soft tissue shadow. Core needle biopsy demonstrates a biphasic pattern of spindle cells and epithelial cells. Cytogenetic testing confirms a t(X;18) translocation. Which of the following best describes this tumor's diagnostic identity and characteristic behavior?

. Ewing sarcoma; classically metastasizes exclusively to bone
. Myxoid liposarcoma; highly responsive to radiation therapy with round cell transformation
. Synovial sarcoma; high-grade sarcoma with a recognized propensity for late pulmonary and regional lymph node metastasis
. Alveolar rhabdomyosarcoma; treated primarily with marginal excision and high-dose chemotherapy
. Epithelioid sarcoma; uniquely presents as a benign-appearing subcutaneous nodule with 100% cure rate

Correct Answer & Explanation

. Synovial sarcoma; high-grade sarcoma with a recognized propensity for late pulmonary and regional lymph node metastasis

Explanation

The diagnosis is Synovial Sarcoma, characterized by the t(X;18) (p11;q11) translocation which results in the SYT-SSX fusion gene. It often presents in young adults near joints (but rarely intra-articular), shows calcification in up to 30% of cases, and has biphasic histology. It is a high-grade sarcoma with a significant rate of metastasis to lungs and a higher propensity for lymph node metastasis (approx 10-20%) compared to most other soft tissue sarcomas.

Question 1931

Topic: 10. Pathology and Oncology

A 16-year-old male presents with chronic knee pain. Radiographs reveal a 2 cm eccentric, purely lytic lesion with a sclerotic rim located entirely within the proximal tibial epiphysis. The proximal tibial physis remains open. Histologic examination demonstrates mononuclear cells with longitudinal nuclear grooves ('coffee bean' nuclei) and a 'chicken-wire' pattern of pericellular calcification. What is the most appropriate surgical treatment?

. Intralesional extended curettage and bone grafting
. Wide en bloc resection with osteoarticular allograft reconstruction
. Neoadjuvant chemotherapy followed by marginal excision
. Transfemoral amputation
. Observation with serial radiographs every 6 months

Correct Answer & Explanation

. Intralesional extended curettage and bone grafting

Explanation

The clinical and histological presentation is classic for Chondroblastoma, a benign but locally aggressive bone tumor found in the epiphyses of skeletally immature patients. The standard treatment is intralesional extended curettage and filling the defect with bone graft or bone cement. Wide resection or amputation is overly aggressive, while observation is inappropriate due to the risk of joint destruction.

Question 1932

Topic: 10. Pathology and Oncology
A 60-year-old male presents with chronic, progressively worsening shoulder pain. Radiographs demonstrate a large lytic lesion with 'ring and arc' calcifications in the proximal humerus and endosteal scalloping involving greater than 2/3 of the cortical thickness. Biopsy confirms grade II conventional chondrosarcoma. Which of the following is the most appropriate management?
. Intralesional curettage with bone grafting
. Wide surgical resection
. Neoadjuvant chemotherapy followed by wide resection
. Radiation therapy alone
. Marginal excision with adjuvant cryotherapy

Correct Answer & Explanation

. Wide surgical resection

Explanation

Conventional chondrosarcoma (Grade II and III) is notoriously resistant to both chemotherapy and radiation therapy. The standard of care for intermediate and high-grade conventional chondrosarcoma is wide surgical resection. Endosteal scalloping >2/3 of the cortex is a strong radiographic indicator of chondrosarcoma rather than benign enchondroma.

Question 1933

Topic: 10. Pathology and Oncology

Which of the following MRI findings is the most reliable distinguishing feature to differentiate a low-grade chondrosarcoma of the proximal femur from a benign enchondroma?

. Lobular growth pattern
. High signal intensity on T2-weighted images
. Peri-tumoral bone marrow edema
. Intralesional popcorn calcification
. Location in the diaphysis

Correct Answer & Explanation

. Peri-tumoral bone marrow edema

Explanation

Differentiating enchondroma from low-grade chondrosarcoma is challenging. However, aggressive features such as peri-tumoral bone marrow edema, soft tissue mass, and deep endosteal scalloping (>2/3 of cortical thickness) strongly favor chondrosarcoma. Lobular growth, T2 high signal, and popcorn calcifications are seen in both.

Question 1934

Topic: 10. Pathology and Oncology

A 16-year-old male is diagnosed with non-metastatic conventional osteosarcoma of the distal femur. He undergoes standard neoadjuvant chemotherapy followed by wide surgical resection. Which of the following is the most important prognostic factor for his overall survival?

. Initial tumor volume at the time of diagnosis
. Specific histologic subtype (e.g., osteoblastic vs. fibroblastic)
. Percentage of tumor necrosis found in the resected specimen
. Serum alkaline phosphatase level at diagnosis
. Absolute distance of the surgical margin from the tumor

Correct Answer & Explanation

. Percentage of tumor necrosis found in the resected specimen

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the single most significant prognostic factor for overall and disease-free survival in conventional osteosarcoma. A 'good responder' is typically defined as having greater than 90% tumor necrosis in the resected specimen.

Question 1935

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a slowly enlarging, painful mass near his knee. MRI demonstrates a well-circumscribed soft tissue mass adjacent to the joint capsule. Biopsy confirms a biphasic tumor containing both epithelial and spindle cell components. Which chromosomal translocation is characteristically associated with 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 findings (biphasic epithelial and spindle cells) are classic for synovial sarcoma. Synovial sarcoma is characterized by the t(X;18)(p11;q11) chromosomal translocation, which results in the SYT-SSX fusion gene.

Question 1936

Topic: Bone Tumors

A 19-year-old male presents with dull, aching pain in his right tibia that is worse at night and dramatically relieved by NSAIDs. CT scan shows a 7 mm radiolucent nidus surrounded by dense reactive sclerosis in the anterior tibial cortex. What is the most appropriate definitive, minimally invasive treatment?

. Intralesional curettage with structural bone grafting
. Wide en bloc surgical resection
. Radiofrequency ablation (RFA)
. Stereotactic body radiation therapy (SBRT)
. Percutaneous ethanol injection

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical presentation (night pain relieved by NSAIDs) and CT findings (radiolucent nidus < 1.5 cm with surrounding sclerosis) are classic for osteoid osteoma. CT-guided radiofrequency ablation (RFA) is the standard of care, offering definitive treatment with minimal morbidity compared to open surgery.

Question 1937

Topic: 10. Pathology and Oncology

A 55-year-old male presents with chronic sacral pain and mild bowel dysfunction. MRI demonstrates a destructive midline mass in the lower sacrum. Biopsy reveals lobules of vacuolated, bubbly cells in a myxoid stroma. Which specific immunohistochemical marker is characteristically positive and diagnostic for this tumor?

. CD99
. Brachyury
. S-100 alone
. MyoD1
. Vimentin alone

Correct Answer & Explanation

. Brachyury

Explanation

The clinical scenario and histology (physaliferous cells) are pathognomonic for a chordoma, a rare primary bone tumor arising from notochordal remnants. Chordomas are uniquely characterized by the nuclear expression of Brachyury, a transcription factor critical for notochord development.

Question 1938

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a slow-growing soft tissue mass in his popliteal fossa. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

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

Explanation

The clinical and histologic presentation (biphasic tumor with epithelial and spindle cells in a peri-articular location) is classic for synovial sarcoma. Synovial sarcoma is uniquely characterized by the t(X;18)(p11;q11) chromosomal translocation, which creates the SYT-SSX fusion gene.

Question 1939

Topic: 10. Pathology and Oncology

A 25-year-old male presents with chronic anterior leg pain. Radiographs demonstrate a multi-loculated, eccentric, osteolytic lesion in the anterior cortex of the tibial diaphysis. Biopsy reveals islands of epithelial cells surrounded by a spindle cell stroma. What is the treatment of choice?

. Intralesional curettage and bone grafting
. Wide surgical resection
. Preoperative chemotherapy followed by wide resection
. Radiation therapy
. Percutaneous radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

The clinical, radiographic, and histologic presentation is classic for adamantinoma, a low-grade malignant bone tumor that predominantly affects the anterior cortex of the tibia. It does not respond well to chemotherapy or radiation. Wide surgical resection is the treatment of choice to minimize recurrence risk.

Question 1940

Topic: Soft Tissue Tumors & Metastasis

A 42-year-old male is diagnosed with a large, deep intramuscular myxoid liposarcoma of the thigh. Molecular analysis of the tumor is most likely to reveal which of the following genetic alterations?

. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(9;22)(q22;q12)
. t(2;13)(q35;q14)
. MDM2 amplification

Correct Answer & Explanation

. t(12;16)(q13;p11)

Explanation

Myxoid liposarcoma is characterized by the t(12;16)(q13;p11) translocation, which creates the FUS-DDIT3 fusion protein. It is uniquely highly sensitive to radiation therapy. MDM2 amplification is characteristic of well-differentiated and dedifferentiated liposarcomas.

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