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10. Pathology and Oncology MCQs

Practice Set 142 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 2821

Topic: 10. Pathology and Oncology

A 55-year-old man presents with progressive pelvic pain. Imaging reveals a large, destructive lesion in the ilium with 'popcorn' intralesional calcifications. Biopsy demonstrates a hypercellular cartilage matrix with pleomorphic binucleated chondrocytes. Which of the following is the most appropriate definitive management for this lesion?

. Neoadjuvant chemotherapy followed by wide surgical resection
. Wide surgical resection alone
. Intralesional curettage with local adjuvant therapy (e.g., phenol, argon beam)
. Definitive external beam radiation therapy
. Denosumab therapy followed by curettage

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

The clinical, radiographic, and histopathologic findings describe a conventional intermediate to high-grade chondrosarcoma. Conventional chondrosarcomas are notably resistant to both chemotherapy and radiation therapy due to their poor vascularity, slow growth, and dense extracellular matrix. Therefore, the cornerstone of treatment for intermediate and high-grade chondrosarcomas (or those located in the pelvis) is wide surgical resection with negative margins alone. Curettage is generally reserved for benign or low-grade cartilaginous lesions in the extremities.

Question 2822

Topic: 10. Pathology and Oncology

A 16-year-old boy presents with a 6-month history of dull, aching back pain that is significantly worse at night and rapidly relieved by NSAIDs. Imaging reveals a 1 cm radiolucent nidus surrounded by reactive sclerosis in the posterior elements of T11. Histologically, the lesion consists of interconnecting woven bone trabeculae with prominent osteoblastic rimming. What is the most common potential clinical consequence of this specific lesion location?

. Neurological deficit from spinal cord compression
. Malignant transformation to secondary osteosarcoma
. Development of painful structural scoliosis
. Spontaneous epidural hematoma
. Contiguous spread leading to diskitis

Correct Answer & Explanation

. Development of painful structural scoliosis

Explanation

The patient has an osteoid osteoma, classically presenting with night pain relieved by NSAIDs and a radiolucent nidus <1.5 cm with reactive sclerosis. When located in the spine (typically the posterior elements), osteoid osteomas frequently cause a painful scoliosis. The concavity of the curve is characteristically directed toward the side of the lesion due to asymmetric paraspinal muscle spasm. Neurological deficits are rare because of the small size of the nidus, unlike osteoblastomas. They do not undergo malignant transformation.

Question 2823

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in the diaphysis of his left femur. A biopsy reveals a small round blue cell tumor. Cytogenetic testing demonstrates a t(11;22)(q24;q12) translocation. This chromosomal translocation results in the fusion of which of the following gene pairs?

. SYT-SSX1
. PAX3-FOXO1
. EWS-FLI1
. TLS-CHOP
. COL1A1-PDGFB

Correct Answer & Explanation

. EWS-FLI1

Explanation

The t(11;22)(q24;q12) translocation is the hallmark genetic aberration of Ewing sarcoma, present in approximately 85% to 90% of cases. It fuses the EWSR1 (Ewing sarcoma breakpoint region 1) gene on chromosome 22 with the FLI1 (Friend leukemia integration 1) gene on chromosome 11, resulting in a chimeric transcription factor (EWS-FLI1) that drives tumorigenesis. SYT-SSX is associated with synovial sarcoma [t(X;18)]. PAX3-FOXO1 is associated with alveolar rhabdomyosarcoma [t(2;13)]. TLS-CHOP is seen in myxoid liposarcoma [t(12;16)]. COL1A1-PDGFB is associated with dermatofibrosarcoma protuberans.

Question 2824

Topic: 10. Pathology and Oncology

A 15-year-old boy completes a course of neoadjuvant chemotherapy and subsequently undergoes a wide resection for a classic, nonmetastatic, high-grade osteosarcoma of the distal femur. Which of the following is considered the single most important prognostic factor for his overall survival?

. Percentage of tumor necrosis on the histologic examination of the resected specimen
. Initial tumor volume on MRI
. Patient's age at the time of diagnosis
. Level of serum alkaline phosphatase at presentation
. Distance of the tumor margin from the joint line

Correct Answer & Explanation

. Percentage of tumor necrosis on the histologic examination of the resected specimen

Explanation

The histologic response to neoadjuvant chemotherapy, determined by the percentage of tumor necrosis in the resected specimen, is the single most reliable prognostic factor for overall survival in patients with classic high-grade osteosarcoma. Greater than 90% necrosis indicates a favorable response and correlates with significantly higher survival rates compared to a poor response (less than 90% necrosis).

Question 2825

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a slow-growing, deep-seated soft-tissue mass in his left foot. MRI demonstrates a well-circumscribed, lobulated mass adjacent to the plantar fascia. Biopsy reveals a biphasic histologic pattern consisting of spindle cells and epithelial cells. What is the characteristic chromosomal translocation associated with this neoplasm?

. 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 findings are diagnostic of synovial sarcoma. This tumor is characterized by the reciprocal chromosomal translocation t(X;18)(p11;q11), which fuses the SYT gene on chromosome 18 with either the SSX1, SSX2, or SSX4 gene on the X chromosome. t(11;22) is seen in Ewing sarcoma. t(12;16) is seen in myxoid liposarcoma. t(9;22) is seen in extraskeletal myxoid chondrosarcoma. t(2;13) is characteristic of alveolar rhabdomyosarcoma.

Question 2826

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive knee pain and swelling. Radiographs reveal an aggressive, permeative, diaphyseal lesion in the distal femur with an associated 'onion-skin' periosteal reaction. A biopsy reveals sheets of uniform, small, round, blue cells. Which of the following specific chromosomal translocations is most strongly associated with this diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical presentation, radiographic findings (diaphyseal permeative lesion, 'onion-skin' periosteal reaction), and histology (small round blue cells) are classic for Ewing sarcoma. Ewing sarcoma is heavily characterized by the t(11;22)(q24;q12) chromosomal translocation in approximately 85% of cases, which creates the EWS-FLI1 fusion protein. Other notable translocations include t(X;18) for synovial sarcoma, t(12;16) for myxoid liposarcoma, and t(2;13) for alveolar rhabdomyosarcoma.

Question 2827

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in his diaphyseal femur. Biopsy reveals a uniform population of small round blue cells. Immunohistochemistry is positive for CD99. Which of the following chromosomal translocations is most characteristic of this specific malignancy?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The patient's presentation and histology are classic for Ewing sarcoma. Ewing sarcoma is characterized by a specific balanced chromosomal translocation, t(11;22)(q24;q12), which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11, forming the EWS-FLI1 fusion protein. Option B t(X;18) is associated with synovial sarcoma. Option C t(12;16) is seen in myxoid liposarcoma. Option D t(2;13) is characteristic of alveolar rhabdomyosarcoma. Option E t(9;22) is the Philadelphia chromosome seen in CML, and also associated with extraskeletal myxoid chondrosarcoma t(9;22)(q22;q12).

Question 2828

Topic: Bone Tumors

A 21-year-old man presents with nocturnal thigh pain that is completely relieved by NSAIDs. Radiographs demonstrate a radiolucent nidus with surrounding dense reactive sclerosis in the femoral diaphysis.

Which of the following molecules is secreted in abnormally high concentrations by the nidus of this lesion, accounting for the characteristic pain pattern?

. Substance P
. Prostaglandin E2 (PGE2)
. Interleukin-1 (IL-1)
. Tumor necrosis factor-alpha (TNF-a)
. Bradykinin

Correct Answer & Explanation

. Prostaglandin E2 (PGE2)

Explanation

The clinical and radiographic presentation describes an osteoid osteoma. The hallmark symptom is intense nocturnal pain that typically responds dramatically to nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin. This distinct clinical feature is due to the nidus of the osteoid osteoma producing high levels of prostaglandins, particularly Prostaglandin E2 (PGE2), up to 100 to 1,000 times normal tissue levels. NSAIDs block cyclooxygenase, inhibiting PGE2 synthesis and relieving the pain.

Question 2829

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a painful mass in his diaphyseal femur. Radiographs demonstrate a permeative lytic lesion with an 'onion-skin' periosteal reaction. Histological evaluation of a core needle biopsy reveals uniform, small round blue cells that stain positive for CD99. Cytogenetic analysis is pending. 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(2;13)(q35;q14)
. t(9;22)(q34;q11)

Correct Answer & Explanation

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

Explanation

The clinical and radiographic presentation, along with the finding of CD99-positive small round blue cells, is highly characteristic of Ewing sarcoma. The most common chromosomal translocation found in Ewing sarcoma is t(11;22)(q24;q12), which results in the EWS-FLI1 fusion protein. t(X;18) is associated with synovial sarcoma, t(12;16) with myxoid liposarcoma, t(2;13) with alveolar rhabdomyosarcoma, and t(9;22) (the Philadelphia chromosome) with chronic myelogenous leukemia.

Question 2830

Topic: 10. Pathology and Oncology
A 55-year-old man presents with a progressively enlarging, painful mass in his right proximal humerus over the last 6 months. Radiographs demonstrate a large radiolucent lesion with intralesional 'popcorn' calcifications and deep endosteal scalloping greater than two-thirds of the cortical thickness. Biopsy confirms a Grade II chondrosarcoma. What is the most appropriate definitive surgical management?
. Intralesional curettage with phenol adjuvant and bone grafting
. Wide surgical resection
. Wide surgical resection followed by multidrug chemotherapy
. Radiation therapy alone
. Neoadjuvant chemotherapy followed by wide resection

Correct Answer & Explanation

. Wide surgical resection

Explanation

Conventional chondrosarcomas (intermediate Grade II and high Grade III) are famously resistant to standard chemotherapy and radiation therapy due to their poor vascularity, slow growth, and abundant extracellular matrix. Therefore, the mainstay of treatment for Grade II and III chondrosarcomas is wide surgical resection with negative margins. Intralesional curettage is only appropriate for benign cartilaginous lesions (like enchondromas) or carefully selected Grade I atypical cartilaginous tumors in the appendicular skeleton.

Question 2831

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in the diaphysis of his left femur. Biopsy reveals small, round blue cells. Cytogenetic analysis demonstrates a t(11;22) translocation. This chromosomal abnormality results in which of the following fusion proteins?

. EWS-FLI1
. SYT-SSX1
. TLS-CHOP
. PAX3-FKHR
. COL1A1-PDGFB

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is characterized by the t(11;22) translocation, which creates the EWS-FLI1 fusion protein. SYT-SSX is seen in synovial sarcoma. TLS-CHOP (or FUS-CHOP) is seen in myxoid liposarcoma. PAX3-FKHR is seen in alveolar rhabdomyosarcoma. COL1A1-PDGFB is associated with dermatofibrosarcoma protuberans.

Question 2832

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive knee pain and swelling that awakens him at night. Radiographs show a permeative, destructive lesion in the distal femoral metadiaphysis with an 'onion-skin' periosteal reaction. Histology shows sheets of uniform small round blue cells. Which of the following immunohistochemical markers or genetic translocations is most characteristic of this lesion?

. t(X;18)
. t(11;22)
. t(12;16)
. MDM2 amplification
. t(2;13)

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized by the t(11;22) translocation, which results in the EWS-FLI1 fusion protein. t(X;18) is seen in synovial sarcoma. t(12;16) is seen in myxoid liposarcoma. MDM2 amplification is seen in atypical lipomatous tumor / well-differentiated liposarcoma and parosteal osteosarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma.

Question 2833

Topic: 10. Pathology and Oncology

A 70-year-old man presents with an enlarging, painful mass in his left thigh. He has a long-standing history of Paget's disease of bone affecting his pelvis and left femur. Radiographs show a destructive lytic lesion in the proximal femur with cortical breakthrough and soft tissue extension. Biopsy confirms a secondary malignancy. What is the most common secondary malignancy arising in the setting of Paget's disease?

. Fibrosarcoma
. Chondrosarcoma
. Ewing sarcoma
. Osteosarcoma
. Multiple myeloma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common secondary malignancy arising in the setting of Paget's disease (Pagetic osteosarcoma), accounting for about 1% of patients with Paget's disease. It typically presents in older adults with worsening pain in a previously affected bone and carries a very poor prognosis compared to primary osteosarcoma in younger patients.

Question 2834

Topic: 10. Pathology and Oncology

A 28-year-old woman presents with a slow-growing, painless mass on the posterior aspect of her distal femur. Radiographs reveal a densely mineralized, lobulated mass attached to the posterior cortex by a broad base, with a radiolucent cleft separating the mass from the underlying cortex ('string sign'). What is the characteristic genetic abnormality associated with this tumor?

. MDM2 amplification
. t(11;22) translocation
. t(X;18) translocation
. EXT1 mutation
. GNAS mutation

Correct Answer & Explanation

. MDM2 amplification

Explanation

The clinical and radiographic presentation is classic for a parosteal osteosarcoma, a low-grade surface osteosarcoma typically found on the posterior aspect of the distal femur. It is characterized genetically by ring chromosomes leading to the amplification of MDM2 and CDK4 genes (chromosome 12q13-15). EXT1 is associated with osteochondromas. GNAS is associated with fibrous dysplasia.

Question 2835

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a destructive diaphyseal lesion of the femur. A biopsy reveals small round blue cells. Cytogenetic analysis demonstrates a t(11;22) translocation. Which of the following fusion proteins is most likely responsible for the pathogenesis of this tumor?

. EWS-FLI1
. SYT-SSX
. FUS-CHOP
. TLS-CHOP
. PAX3-FKHR

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is a malignant primary bone tumor characterized by small round blue cells. It is most commonly associated with a t(11;22) chromosomal translocation, which results in the EWS-FLI1 fusion protein. SYT-SSX is associated with synovial sarcoma (t(X;18)). FUS-CHOP (also known as TLS-CHOP) is associated with myxoid liposarcoma (t(12;16)). PAX3-FKHR is associated with alveolar rhabdomyosarcoma (t(2;13)).

Question 2836

Topic: 10. Pathology and Oncology

A 45-year-old woman undergoes wide resection of a deep soft tissue sarcoma of the thigh. Histological examination reveals a biphasic pattern consisting of both epithelial and spindle cell components. Cytogenetic testing demonstrates a t(X;18) translocation. What is the most likely diagnosis?

. Synovial sarcoma
. Clear cell sarcoma
. Alveolar soft part sarcoma
. Epithelioid sarcoma
. Myxoid liposarcoma

Correct Answer & Explanation

. Synovial sarcoma

Explanation

The presence of a t(X;18)(p11;q11) chromosomal translocation is the hallmark of synovial sarcoma, leading to the SYT-SSX fusion gene. Synovial sarcoma often presents in young adults in the deep soft tissues of the extremities (most commonly the lower extremity). The tumor can exhibit a biphasic histologic pattern (epithelial and spindle cells) or a monophasic spindle cell pattern. Clear cell sarcoma is associated with t(12;22), myxoid liposarcoma with t(12;16), and alveolar soft part sarcoma with t(X;17).

Question 2837

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a 2-month history of worsening thigh pain, particularly at night. Radiographs reveal a permeative diaphyseal lesion in the femur with an extensive 'onion-skin' periosteal reaction. Biopsy demonstrates sheets of small round blue cells that stain strongly for CD99. Which of the following cytogenetic abnormalities is most characteristic of this patient's diagnosis?

. t(X;18)(p11;q11)
. t(11;22)(q24;q12)
. 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, a small round blue cell tumor that typically arises in the diaphysis of long bones. The classic radiographic appearance includes a permeative destructive lesion with 'onion-skin' periosteal reaction. CD99 positivity is characteristic. The hallmark cytogenetic abnormality is t(11;22)(q24;q12), resulting in the EWS-FLI1 fusion protein. t(X;18) is seen in synovial sarcoma. t(12;16) is seen in myxoid liposarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(9;22) is the Philadelphia chromosome seen in CML.

Question 2838

Topic: 10. Pathology and Oncology

A 12-year-old girl is diagnosed with a conventional high-grade osteosarcoma of the distal femur. Her family history is notable for a mother who died of premenopausal breast cancer at age 32 and a brother who was treated for an adrenocortical carcinoma. A mutation in which of the following genes is the most likely underlying cause of this patient's susceptibility?

. RB1
. NF1
. APC
. TP53
. PTEN

Correct Answer & Explanation

. TP53

Explanation

The patient's family history of premenopausal breast cancer, adrenocortical carcinoma, and her presentation with osteosarcoma are highly suggestive of Li-Fraumeni syndrome. Li-Fraumeni syndrome is an autosomal dominant disorder caused by germline mutations in the TP53 tumor suppressor gene. This leads to a significantly increased risk of developing various malignancies, including osteosarcoma, soft-tissue sarcomas, breast cancer, brain tumors, and adrenocortical carcinoma. RB1 mutations cause hereditary retinoblastoma, which also increases osteosarcoma risk, but does not fit the associated familial cancer pattern.

Question 2839

Topic: Bone Tumors

An 18-year-old male presents with a 6-month history of dull, aching back pain that is worsened at night. He reports that the pain is only mildly relieved by ibuprofen. Imaging demonstrates a 2.5 cm radiolucent lesion with a central nidus located in the posterior elements of the L4 vertebra. Histology shows interlacing trabeculae of woven bone surrounded by prominent osteoblasts. What is the most likely diagnosis?

. Osteoid osteoma
. Aneurysmal bone cyst
. Osteoblastoma
. Osteochondroma
. Chondromyxoid fibroma

Correct Answer & Explanation

. Osteoblastoma

Explanation

The patient's presentation is most consistent with an osteoblastoma. While histologically identical to an osteoid osteoma (showing interlacing trabeculae of woven bone lined by prominent osteoblasts), an osteoblastoma is distinguished by its larger size (> 2 cm). Clinically, the pain associated with osteoblastoma is often less severe at night and less responsive to NSAIDs compared to osteoid osteoma. Both tumors have a predilection for the posterior elements of the spine.

Question 2840

Topic: 10. Pathology and Oncology

A 16-year-old girl presents with a rapidly enlarging, painful mass in her proximal humerus. Radiographs show an expansile, eccentric, multiloculated lytic lesion. Magnetic resonance imaging (MRI) demonstrates multiple fluid-fluid levels. Biopsy reveals blood-filled cystic spaces lacking an endothelial lining. Which of the following genetic alterations is the primary driver of this lesion?

. GNAS somatic mutation
. EXT1 or EXT2 gene mutation
. USP6 gene rearrangement
. H3F3A mutation
. MDM2 amplification

Correct Answer & Explanation

. USP6 gene rearrangement

Explanation

The clinical, radiographic, and histological findings describe an Aneurysmal Bone Cyst (ABC). Primary ABCs are now recognized as true neoplasms driven by recurrent translocations involving the USP6 gene on chromosome 17p13. This rearrangement leads to USP6 upregulation, which activates matrix metalloproteinases and promotes cystic bone destruction. GNAS mutations are seen in fibrous dysplasia; EXT mutations in osteochondromas; H3F3A mutations in giant cell tumors of bone and chondroblastomas; and MDM2 amplification in parosteal osteosarcoma and atypical lipomatous tumors.

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