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10. Pathology and Oncology MCQs

Practice Set 332 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 6621

Topic: 10. Pathology and Oncology

A 22-year-old man presents with a painless lump on his proximal humerus. Radiographs show a surface lesion with underlying cortical saucerization and a sclerotic margin.

Histology shows lobules of hyaline cartilage. What is the most appropriate management?

. Wide surgical resection
. Neoadjuvant chemotherapy and wide resection
. Curettage and bone grafting
. Observation
. Radiation therapy

Correct Answer & Explanation

. Observation

Explanation

The clinical, radiographic, and histologic findings are diagnostic of a periosteal chondroma, a benign cartilage tumor. Asymptomatic lesions can be safely managed with observation.

Question 6622

Topic: Bone Tumors

A 16-year-old male is diagnosed with an osteoblastic osteosarcoma of the distal femur. What is the most sensitive imaging modality for detecting 'skip metastases' within the same bone?

. CT scan of the lower extremity without contrast
. Technetium-99m bone scan
. PET-CT scan
. MRI of the entire femur (T1-weighted sequences)
. Ultrasound of the thigh

Correct Answer & Explanation

. MRI of the entire femur (T1-weighted sequences)

Explanation

T1-weighted MRI of the entire involved bone is the gold standard for identifying skip metastases in osteosarcoma. Their presence significantly alters surgical planning and worsens the prognosis.

Question 6623

Topic: 10. Pathology and Oncology

A 40-year-old male presents with hip pain. Radiographs demonstrate a lytic lesion in the proximal femoral epiphysis. Biopsy reveals abundant cells with distinct borders, clear cytoplasm, and central nuclei scattered among hyaline cartilage. What is the most appropriate treatment?

. Curettage and cryotherapy
. Curettage and bone grafting
. Wide surgical resection
. Chemotherapy followed by wide resection
. Radiation therapy

Correct Answer & Explanation

. Wide surgical resection

Explanation

Clear cell chondrosarcoma typically presents in the epiphysis of long bones in adults. It is a low-to-intermediate grade malignant tumor that requires wide surgical resection to minimize the high risk of local recurrence.

Question 6624

Topic: 10. Pathology and Oncology

A 35-year-old female presents with a painless, palpable mass on her right index finger. Radiographs reveal a centrally located lytic lesion with stippled calcifications and mild cortical expansion in the proximal phalanx.

What is the most likely diagnosis?

. Enchondroma
. Giant cell tumor of bone
. Chondroblastoma
. Osteoid osteoma
. Aneurysmal bone cyst

Correct Answer & Explanation

. Enchondroma

Explanation

Enchondroma is the most common primary bone tumor in the hand, typically presenting as a centrally located lytic lesion with stippled calcifications and endosteal scalloping. They are benign, cartilage-forming tumors that often remain asymptomatic unless complicated by a pathologic fracture.

Question 6625

Topic: 10. Pathology and Oncology

A 24-year-old male presents with localized, dull ache over his proximal humerus. Imaging demonstrates a surface-based lesion with a sclerotic margin and 'saucerization' of the underlying outer cortex, with no medullary extension.

What is the most likely diagnosis?

. Periosteal chondroma
. Periosteal osteosarcoma
. Osteochondroma
. Ewing sarcoma
. Parosteal osteosarcoma

Correct Answer & Explanation

. Periosteal chondroma

Explanation

Periosteal chondromas are benign surface tumors of cartilage that characteristically produce saucerization (a well-defined cortical depression) with a sclerotic rim. Unlike osteochondromas, they do not show medullary continuity.

Question 6626

Topic: 10. Pathology and Oncology

A 16-year-old boy who underwent wide resection and chemotherapy for distal femoral osteosarcoma 2 years ago now presents with two new, isolated 1.5 cm nodules in the right lung base. Staging shows no other sites of disease. What is the standard of care for these lesions?

. Palliative care
. Second-line chemotherapy only
. Pulmonary metastasectomy
. Stereotactic body radiation therapy (SBRT)
. Isolated lung perfusion

Correct Answer & Explanation

. Pulmonary metastasectomy

Explanation

Pulmonary metastasectomy is the gold standard for isolated, resectable lung metastases in osteosarcoma patients. Complete surgical resection of all metastatic deposits offers the best chance for long-term survival.

Question 6627

Topic: 10. Pathology and Oncology

A 12-year-old girl is evaluated for multiple bony deformities. Radiographs reveal numerous enchondromas throughout the appendicular skeleton. Physical examination shows multiple bluish, soft-tissue masses on her limbs consistent with hemangiomas. Which syndrome does this patient have?

. Multiple hereditary exostoses
. McCune-Albright syndrome
. Maffucci syndrome
. Ollier disease
. Neurofibromatosis type 1

Correct Answer & Explanation

. Maffucci syndrome

Explanation

Maffucci syndrome is characterized by the presence of multiple enchondromas (enchondromatosis) and soft-tissue hemangiomas. Patients with Maffucci syndrome carry a significantly higher risk of malignant transformation to chondrosarcoma (up to 100% over a lifetime) compared to Ollier disease.

Question 6628

Topic: Bone Tumors

Recent genomic profiling has identified specific somatic mutations that are highly prevalent in solitary enchondromas, central chondrosarcomas, and syndromic enchondromatosis. Which of the following mutations is most characteristically involved?

. TP53
. RB1
. IDH1 or IDH2
. EXT1 or EXT2
. GNAS

Correct Answer & Explanation

. IDH1 or IDH2

Explanation

Mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2) are found in the vast majority of enchondromas and central chondrosarcomas. They result in the production of an oncometabolite, 2-hydroxyglutarate, which alters cellular epigenetics.

Question 6629

Topic: 10. Pathology and Oncology

A 55-year-old male presents with deep, progressive shoulder pain. Radiographs show a cartilaginous lesion in the proximal humerus. Which of the following MRI findings most strongly supports a diagnosis of high-grade chondrosarcoma over a benign enchondroma?

. Presence of stippled calcification
. Lesion size less than 3 cm
. Endosteal scalloping involving >2/3 of cortical thickness with soft tissue extension
. Location in the metaphysis
. Lack of surrounding bone marrow edema

Correct Answer & Explanation

. Endosteal scalloping involving >2/3 of cortical thickness with soft tissue extension

Explanation

Deep endosteal scalloping (>2/3 of cortical thickness), cortical breakthrough, and soft tissue extension are hallmark imaging signs of malignant transformation to chondrosarcoma. Enchondromas typically display minimal endosteal scalloping.

Question 6630

Topic: Bone Tumors

A 15-year-old male complains of chronic knee pain. Radiographs reveal an eccentric, lytic lesion in the distal femoral epiphysis that crosses an open physis. Histology shows polygonal cells with grooved nuclei and fine, pericellular calcifications. What is the diagnosis?

. Chondroblastoma
. Chondrosarcoma
. Enchondroma
. Chondromyxoid fibroma
. Osteosarcoma

Correct Answer & Explanation

. Chondroblastoma

Explanation

Chondroblastoma characteristically occurs in the epiphysis or apophysis of young patients. Histologic hallmarks include mononuclear chondroblasts with grooved nuclei (coffee bean appearance) and pericellular 'chicken-wire' calcification.

Question 6631

Topic: 10. Pathology and Oncology

A 22-year-old male presents with a localized, painful swelling on the distal humerus. Imaging confirms a surface cartilaginous lesion.

Biopsy confirms a benign hyaline cartilage tumor. What is the most appropriate management?

. Observation alone
. Marginal excision including the underlying sclerotic cortex
. Wide en bloc resection
. Systemic chemotherapy
. Radiation therapy

Correct Answer & Explanation

. Marginal excision including the underlying sclerotic cortex

Explanation

For symptomatic periosteal chondromas, the treatment of choice is marginal excision, which should include the underlying saucerized sclerotic cortex to minimize recurrence risk. Wide resection is unnecessary for these benign lesions.

Question 6632

Topic: 10. Pathology and Oncology

A 40-year-old male presents with a lytic lesion in the proximal femoral epiphysis. Biopsy reveals cells with abundant clear cytoplasm and distinct boundaries in a background of hyaline cartilage and reactive bone. What is the recommended treatment for this lesion?

. Intralesional curettage with phenol
. Wide en bloc resection
. Radiation therapy
. Neoadjuvant chemotherapy followed by curettage
. Radiofrequency ablation

Correct Answer & Explanation

. Wide en bloc resection

Explanation

Clear cell chondrosarcoma is a low-grade malignant tumor that uniquely favors the epiphysis, often mimicking chondroblastoma. The standard of care is wide en bloc resection, as intralesional procedures carry an unacceptably high recurrence rate.

Question 6633

Topic: 10. Pathology and Oncology

A 30-year-old male is diagnosed with synovial sarcoma of the distal thigh. Following wide local excision, he is monitored for distant metastasis. What is the most common site of metastasis for this tumor?

. Liver
. Brain
. Bone
. Lymph nodes
. Lungs

Correct Answer & Explanation

. Lungs

Explanation

The lungs are the most common site of distant metastasis for nearly all high-grade soft tissue sarcomas of the extremities, including synovial sarcoma. Surveillance imaging must routinely include non-contrast chest CT.

Question 6634

Topic: 10. Pathology and Oncology

Which histologic feature is the hallmark of dedifferentiated chondrosarcoma?

. Benign cartilage interspersed with reactive woven bone
. A low-grade cartilaginous component abruptly juxtaposed to a high-grade non-cartilaginous spindle cell sarcoma
. Sheets of uniform small round blue cells
. Chondroblasts surrounded by 'chicken-wire' calcification
. Stellate cells in a heavily myxoid background

Correct Answer & Explanation

. A low-grade cartilaginous component abruptly juxtaposed to a high-grade non-cartilaginous spindle cell sarcoma

Explanation

Dedifferentiated chondrosarcoma is characterized by a bimorphic histologic pattern showing an abrupt transition between a low-grade cartilage tumor and a high-grade, non-cartilaginous sarcoma (e.g., osteosarcoma, fibrosarcoma). It carries a very poor prognosis.

Question 6635

Topic: 10. Pathology and Oncology

A 20-year-old female presents with an eccentric, multiloculated, lytic lesion with a sclerotic rim in the proximal tibial metaphysis. Biopsy shows stellate and spindle cells in a myxoid background with scattered osteoclast-like giant cells. What is the most likely diagnosis?

. Enchondroma
. Chondromyxoid fibroma
. Chondrosarcoma
. Periosteal chondroma
. Mesenchymal chondrosarcoma

Correct Answer & Explanation

. Chondromyxoid fibroma

Explanation

Chondromyxoid fibroma (CMF) classically presents as an eccentric, lytic metaphyseal lesion with a sclerotic rim. Histologically, it demonstrates lobules of stellate/spindle cells in a myxoid background, often with giant cells at the lobular peripheries.

Question 6636

Topic: Bone Tumors

A 14-year-old girl is diagnosed with a conventional high-grade intramedullary osteosarcoma of the distal femur. What is the standard neoadjuvant chemotherapy regimen utilized to improve survival and prevent metastasis?

. Methotrexate, Doxorubicin (Adriamycin), and Cisplatin
. Ifosfamide and Etoposide
. Vincristine, Doxorubicin, and Cyclophosphamide
. Imatinib mesylate
. Denosumab

Correct Answer & Explanation

. Methotrexate, Doxorubicin (Adriamycin), and Cisplatin

Explanation

The standard of care for high-grade osteosarcoma is the 'MAP' regimen, consisting of high-dose Methotrexate, Adriamycin (Doxorubicin), and Cisplatin. This regimen significantly improves long-term survival by eradicating micrometastatic disease.

Question 6637

Topic: 10. Pathology and Oncology

A 10-year-old boy presents with a permeative lesion in the femoral diaphysis and an 'onion-skin' periosteal reaction. Molecular testing of the biopsy specimen is most likely to reveal which of the following chromosomal translocations?

. 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(11;22)(q24;q12)

Explanation

Ewing sarcoma is classically associated with the t(11;22)(q24;q12) translocation, leading to the EWSR1-FLI1 fusion gene. This drives the pathogenesis of the small round blue cell tumor.

Question 6638

Topic: 10. Pathology and Oncology

Mesenchymal chondrosarcoma is a rare, aggressive bone tumor. Which of the following characteristics is true regarding its clinical behavior?

. It has a high rate of late metastasis, often occurring more than 5 years after initial treatment
. It follows a completely benign course if resected marginally
. It shows an excellent curative response to RANKL inhibitors
. It almost always transforms into conventional osteosarcoma
. It is predominantly found in the short tubular bones of the hand

Correct Answer & Explanation

. It has a high rate of late metastasis, often occurring more than 5 years after initial treatment

Explanation

Mesenchymal chondrosarcoma is an aggressive variant known for its bimorphic histology (small round blue cells and cartilage islands) and a high propensity for late metastasis, often recurring or metastasizing a decade or more after initial therapy.

Question 6639

Topic: 10. Pathology and Oncology

A 60-year-old man had a wide local excision and radiation for a high-grade undifferentiated pleomorphic sarcoma of the thigh 18 months ago. Routine surveillance CT reveals an isolated 2 cm metastasis in the left lower pulmonary lobe. What is the most appropriate treatment recommendation?

. Pulmonary metastasectomy
. Systemic chemotherapy exclusively
. Definitive external beam radiation to the lung
. Observation until symptoms develop
. Hip disarticulation

Correct Answer & Explanation

. Pulmonary metastasectomy

Explanation

For soft tissue sarcoma patients presenting with isolated, resectable pulmonary metastasis (with no extrapulmonary disease and control of the primary site), pulmonary metastasectomy provides the best chance for extended survival.

Question 6640

Topic: Bone Tumors

A 26-year-old woman is evaluated for a localized mass on the surface of her proximal tibia. Radiographs reveal saucerization of the underlying cortex and a sclerotic margin.

Which radiographic feature best differentiates this lesion from a periosteal osteosarcoma?

. Saucerization of the underlying cortex with a sclerotic rim
. Sunburst periosteal reaction with perpendicular bone formation
. Presence of a Codman triangle
. Medullary continuity with the marrow cavity
. Popcorn calcification within the medullary canal

Correct Answer & Explanation

. Saucerization of the underlying cortex with a sclerotic rim

Explanation

Periosteal chondroma typically causes saucerization (a scallop/depression) of the underlying cortex with a thickened sclerotic rim. In contrast, periosteal osteosarcoma typically shows aggressive perpendicular new bone formation (sunburst) without the mature sclerotic rim.

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