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10. Pathology and Oncology MCQs

Practice Set 115 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 2281

Topic: 10. Pathology and Oncology



A 14-year-old boy presents with pain and swelling in the mid-shaft of his femur. Radiographs display a permeative, diaphyseal lytic lesion with an 'onion-skin' periosteal reaction. Biopsy reveals small, round, blue cells. Which chromosomal translocation is most characteristically associated with this malignancy?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is a highly malignant small round blue cell tumor that typically arises in the diaphysis of long bones in children and adolescents. It is strongly associated with the balanced chromosomal translocation t(11;22)(q24;q12), which results in the EWS-FLI1 fusion protein. This unique fusion drives the pathogenesis of the tumor.

Question 2282

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive pain and swelling in his mid-thigh over the last two months. Radiographs reveal a permeative, diaphyseal lytic lesion with an 'onion skin' periosteal reaction.

Biopsy demonstrates uniform, small round blue cells. What is the most common chromosomal translocation associated with this patient's diagnosis?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical presentation and histology are classic for Ewing sarcoma. The most common genetic anomaly associated with Ewing sarcoma is the t(11;22)(q24;q12) translocation, which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11, occurring in about 85% of cases. t(X;18) is seen in Synovial Sarcoma. t(12;16) is seen in Myxoid Liposarcoma. t(2;13) is seen in Alveolar Rhabdomyosarcoma.

Question 2283

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a permeative lytic lesion in the diaphysis of the femur with an 'onion skin' periosteal reaction. A biopsy confirms small blue round cells. Which chromosomal translocation is pathognomonic for this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation is classic for Ewing Sarcoma. The pathognomonic genetic abnormality is a translocation between chromosomes 11 and 22 [t(11;22)(q24;q12)], which leads to the formation of the EWS-FLI1 fusion protein. This occurs in approximately 85% of cases. t(X;18) is Synovial Sarcoma; t(9;22) is myxoid chondrosarcoma (and CML); t(2;13) is Alveolar Rhabdomyosarcoma; t(12;16) is Myxoid Liposarcoma.

Question 2284

Topic: 10. Pathology and Oncology

A 30-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic, epiphyseal lesion in the distal femur that extends to the subchondral bone without a sclerotic margin. Biopsy reveals numerous multinucleated giant cells interspersed in a background of mononuclear stromal cells. Which cell type represents the true neoplastic component of this tumor?

. Osteoclasts
. Osteoblasts
. Mononuclear stromal cells
. Macrophages
. Chondroblasts

Correct Answer & Explanation

. Mononuclear stromal cells

Explanation

The diagnosis is Giant Cell Tumor (GCT) of bone. Despite the striking histological presence of multinucleated giant cells (which give the tumor its name), the true neoplastic cells are the mononuclear stromal cells. These spindle-shaped stromal cells express high levels of RANKL (Receptor Activator of Nuclear factor Kappa-B Ligand), which recruits and stimulates normal host macrophages to fuse into the reactive, bone-resorbing multinucleated giant cells.

Question 2285

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a progressive, dull ache in his proximal femur. Radiographs reveal a lytic lesion in the femoral head epiphysis with a sclerotic margin. Biopsy shows tumor cells with abundant clear cytoplasm and central nuclei, interspersed with coarse woven bone and osteoclast-like giant cells. What is the most appropriate treatment?

. Intralesional curettage and bone grafting.
. Wide surgical resection.
. Preoperative radiation followed by curettage.
. Chemotherapy and limb salvage.
. Radiofrequency ablation.

Correct Answer & Explanation

. Wide surgical resection.

Explanation

Clear cell chondrosarcoma typically presents in the epiphyses of long bones (most commonly the proximal femur or humerus) in young adults. It is considered a low-grade malignant bone tumor. Standard treatment is wide surgical resection, as intralesional curettage results in an unacceptably high local recurrence rate.

Question 2286

Topic: 10. Pathology and Oncology

A 19-year-old male presents with severe night pain in his right mid-tibia that is predictably relieved by ibuprofen.

Imaging shows a 0.8 cm radiolucent nidus surrounded by dense reactive sclerosis. The pain associated with this lesion is mediated by the overproduction of which of the following?

. Interleukin-6
. Tumor Necrosis Factor-alpha
. Prostaglandin E2
. Substance P
. Bradykinin

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteoma is a benign bone-forming tumor characterized by a small nidus (<1.5 cm) that produces high levels of Prostaglandin E2 (PGE2) via COX-2 expression. This robust PGE2 production causes intense vasodilation and localized pain, which is characteristically worse at night and dramatically responsive to NSAIDs.

Question 2287

Topic: 10. Pathology and Oncology

A 15-year-old male presents with deep knee pain. Radiographs reveal a mixed lytic and sclerotic lesion in the distal femur metaphysis with a "sunburst" periosteal reaction. Biopsy confirms high-grade conventional osteosarcoma. What is the most appropriate next step in management?

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

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 (preoperative) chemotherapy, followed by wide surgical resection (limb-sparing surgery if feasible), and then adjuvant (postoperative) chemotherapy.

Question 2288

Topic: Bone Tumors

A 10-year-old boy incidentally undergoes an x-ray for a minor ankle sprain, revealing a cortically based, radiolucent lesion surrounded by a thick rim of reactive sclerosis in the distal tibial diaphysis. He describes severe pain at night that is dramatically relieved by NSAIDs. What is the most likely diagnosis?

. Osteoid osteoma
. Osteoblastoma
. Non-ossifying fibroma
. Chondroblastoma
. Eosinophilic granuloma

Correct Answer & Explanation

. Osteoid osteoma

Explanation

Osteoid osteoma classically presents in children/young adults with night pain relieved by NSAIDs. Radiographically, it appears as a small radiolucent nidus (<1.5 cm) surrounded by dense reactive sclerosis, typically in the cortex of long bones.

Question 2289

Topic: 10. Pathology and Oncology
A 15-year-old male presents with knee pain, and biopsy confirms conventional high-grade osteosarcoma of the distal femur. Following neoadjuvant chemotherapy and wide resection, what histologic finding represents the most significant prognostic factor for long-term survival in localized disease?
. High mitotic index (>10 per HPF)
. Tumor necrosis rate < 90% following neoadjuvant chemotherapy
. Presence of chondroblastic elements
. Extension of tumor through the physis
. Presence of osteoid matrix throughout the tumor

Correct Answer & Explanation

. Tumor necrosis rate < 90% following neoadjuvant chemotherapy

Explanation

In localized high-grade osteosarcoma, the degree of tumor necrosis after induction (neoadjuvant) chemotherapy is one of the most powerful prognostic indicators. A "good response" is typically defined as ≥ 90% necrosis (Huvos grade III or IV). A necrosis rate of less than 90% is an adverse prognostic factor for survival.

Question 2290

Topic: 10. Pathology and Oncology

A 48-year-old female presents with chronic, dull pain in her right proximal humerus that is worse at night. Radiographs demonstrate a well-circumscribed, lytic lesion with central 'popcorn' calcifications. MRI confirms a cartilaginous matrix, and cortical endosteal scalloping is present measuring 80% of the cortical thickness.

What is the most appropriate definitive management?

. Intralesional curettage alone
. Intralesional curettage with phenol and polymethylmethacrylate (PMMA)
. Neoadjuvant chemotherapy followed by wide resection
. Wide surgical resection with negative margins
. Definitive radiation therapy

Correct Answer & Explanation

. Wide surgical resection with negative margins

Explanation

The clinical presentation (pain at night) and radiographic findings (endosteal scalloping >2/3 of the cortical thickness, popcorn calcifications) are highly suspicious for a chondrosarcoma rather than a benign enchondroma. Low to intermediate-grade chondrosarcomas are managed with wide surgical resection, as they do not respond well to chemotherapy or radiation therapy.

Question 2291

Topic: 10. Pathology and Oncology
A 15-year-old male presents with distal femoral pain. Biopsy confirms conventional high-grade osteosarcoma. He undergoes 10 weeks of neoadjuvant chemotherapy. Following wide surgical resection, histopathologic analysis is performed. Which of the following findings defines a 'good response' to chemotherapy, serving as the strongest prognostic indicator for overall survival?
. Greater than 90% tumor necrosis
. Greater than 99% tumor necrosis
. High presence of intralesional CD8+ lymphocytes
. Decrease in overall tumor volume by greater than 50%
. Complete ossification of the tumor matrix

Correct Answer & Explanation

. Greater than 90% tumor necrosis

Explanation

The histologic response to neoadjuvant chemotherapy is the most important prognostic factor in osteosarcoma. A 'good response' is traditionally defined by the Huvos grading system as >90% tumor necrosis (Grade III is 91-99%, Grade IV is 100% necrosis). Patients with a good response have significantly improved long-term survival.

Question 2292

Topic: 10. Pathology and Oncology

A 10-year-old boy presents with severe, unrelenting thigh pain. Radiographs reveal a permeative diaphyseal lesion in the femur with a multilamellated 'onion-skin' periosteal reaction. Genetic testing reveals a t(11;22) chromosomal translocation. Which fusion protein is characteristic of this tumor?

. SYT-SSX1
. EWS-FLI1
. TLS-CHOP
. PAX3-FKHR
. MYC amplification

Correct Answer & Explanation

. EWS-FLI1

Explanation

The clinical presentation and 'onion-skin' periosteal reaction suggest Ewing Sarcoma. The hallmark of Ewing Sarcoma is the t(11;22)(q24;q12) translocation, which results in the EWS-FLI1 fusion protein. SYT-SSX is seen in synovial sarcoma, TLS-CHOP in myxoid liposarcoma, and PAX3-FKHR in alveolar rhabdomyosarcoma.

Question 2293

Topic: 10. Pathology and Oncology

A 16-year-old boy presents with progressive knee pain. Radiographs demonstrate a destructive distal femoral lesion with a 'sunburst' periosteal reaction as shown below. Biopsy confirms high-grade intramedullary osteosarcoma. Following neoadjuvant therapy and surgical resection, what is the single most important prognostic factor for long-term survival?

. Anatomic location of the tumor
. Histologic tumor necrosis response to neoadjuvant chemotherapy
. Preoperative serum alkaline phosphatase level
. Absolute tumor volume prior to resection
. Extent of soft tissue intramedullary extension

Correct Answer & Explanation

. Histologic tumor necrosis response to neoadjuvant chemotherapy

Explanation

The image and presentation are classic for a conventional high-grade osteosarcoma. While factors like tumor size and alkaline phosphatase have prognostic value, the most critical prognostic indicator for overall survival is the degree of histologic necrosis (typically aiming for >90% necrosis) following neoadjuvant chemotherapy.

Question 2294

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a painful mass around his distal femur. Biopsy reveals a high-grade pleomorphic spindle cell neoplasm producing malignant osteoid. Mutations in which of the following tumor suppressor genes are most strongly implicated in the pathogenesis of this disease, particularly in familial syndromes like Li-Fraumeni?

. EXT1
. NF1
. TP53
. PTEN
. APC

Correct Answer & Explanation

. TP53

Explanation

The patient has osteosarcoma, the most common primary malignant bone tumor in youths, characterized by the production of malignant osteoid. The tumor suppressor genes most commonly implicated in the pathogenesis of osteosarcoma are TP53 and RB1. Li-Fraumeni syndrome is caused by a germline mutation in the TP53 gene and is associated with a markedly increased risk of developing osteosarcoma, breast cancer, brain tumors, and leukemias.

Question 2295

Topic: 10. Pathology and Oncology

A 32-year-old female presents with progressive knee pain. Radiographs reveal an eccentric, lytic, epiphyseal-metaphyseal lesion in the proximal tibia with a 'soap bubble' appearance extending to the subchondral bone. Biopsy shows multinucleated giant cells in a background of mononuclear stromal cells. Which of the following targeted medical therapies is most appropriate for a surgically unresectable lesion of this type?

. Imatinib
. Denosumab
. Methotrexate
. Bisphosphonates
. Rituximab

Correct Answer & Explanation

. Denosumab

Explanation

The clinical and radiographic presentation is classic for a Giant Cell Tumor (GCT) of bone. The neoplastic cells in GCT are the mononuclear stromal cells, which express RANK-L (Receptor Activator of Nuclear factor Kappa-B Ligand). This expression recruits and activates the reactive multinucleated giant cells, which are essentially osteoclasts, leading to massive bone lysis. Denosumab is a monoclonal antibody that targets and inhibits RANK-L, thereby cutting off the signal to osteoclasts. It is the medical treatment of choice for unresectable, recurrent, or metastatic giant cell tumors.

Question 2296

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a slow-growing, painful soft tissue mass in the posterior aspect of her knee. An MRI demonstrates a well-circumscribed mass adjacent to the joint capsule.

Biopsy reveals a biphasic pattern consisting of both epithelial-like and spindle cells. Which of the following cytogenetic abnormalities is most characteristic of this lesion?

. 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 histological presentation describes a synovial sarcoma, which characteristically features a biphasic microscopic pattern (epithelial and spindle cells). The hallmark cytogenetic translocation for synovial sarcoma is t(X;18)(p11;q11), leading to the SYT-SSX fusion gene. t(11;22) is seen in Ewing sarcoma; t(12;16) in myxoid liposarcoma; t(2;13) in alveolar rhabdomyosarcoma; and t(9;22) in extraskeletal myxoid chondrosarcoma.

Question 2297

Topic: 10. Pathology and Oncology

A 60-year-old male with a history of lung cancer presents with thigh pain. Radiographs reveal a metastatic lesion in the femur. You apply Mirels' criteria to determine if prophylactic fixation is indicated. Which of the following specific findings yields a maximum score of 3 points in its respective category within Mirels' system?

. Location in the upper extremity
. Blastic nature of the lesion
. Mild degree of pain
. Size of the lesion occupying 1/3 to 2/3 of the cortex
. Peritrochanteric location

Correct Answer & Explanation

. Peritrochanteric location

Explanation

Mirels' criteria uses four categories to predict pathologic fracture risk: Site, Pain, Lesion type, and Size. Site scores are: Upper limb (1), Lower limb (2), Peritrochanteric (3). Pain: Mild (1), Moderate (2), Functional/Severe (3). Lesion type: Blastic (1), Mixed (2), Lytic (3). Size: <1/3 (1), 1/3-2/3 (2), >2/3 (3). Thus, a peritrochanteric location yields 3 points.

Question 2298

Topic: 10. Pathology and Oncology

A 14-year-old patient has anterior knee pain. Radiographs, an MRI scan, and biopsy specimens are shown in Figures 6a through 6e. What is the most likely diagnosis?

. Unicameral bone cyst
. Aneurysmal bone cyst
. Giant cell tumor
. Chondromalacia
. Ewing's sarcoma

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

Although the imaging studies are consistent with a unicameral bone cyst, aneurysmal bone cyst, or giant cell tumor, the histology shows small round blue cells that are typical of Ewing's sarcoma. Although Ewing's sarcoma frequently occurs in the diaphysis, it can occur in the metaphysis.

Question 2299

Topic: 10. Pathology and Oncology

A 15-year-old girl with a midshaft fibular lesion has histologic findings consistent with Ewing's sarcoma. Following induction chemotherapy, local control typically consists of

Basic Science 2005 Practice Questions: Set 1 (Solved) - Figure 46

. radiation therapy only.
. curettage and bone grafting.
. wide resection.
. below-knee amputation.
. observation.

Correct Answer & Explanation

. wide resection.

Explanation

The current treatment regimen for Ewing's sarcoma typically involves induction chemotherapy followed by local control and further chemotherapy. Local control consists of surgery only, radiation therapy only, or a combination of the two. In bones that are easily resectable (expendable) with wide margins, surgery is usually recommended. For areas that cannot be resected (ie, large bulky pelvic tumors), radiation therapy alone is sometimes the preferred method of local control. If surgery is chosen and the margins are close, radiation therapy can be used as an adjuvant treatment. Amputation is rarely required for an isolated fibular lesion. Observation without adequate local control results in local recurrence. Nesbit ME Jr, Gehan EA, Burgert EO Jr, et al: Multimodality therapy for the treatment of primary, non-metastatic Ewing's sarcoma of the bone: A long-term follow-up of the first intergroup study. J Clin Oncol 1990;8:1664-1674.

Question 2300

Topic: 10. Pathology and Oncology

A 14-year-old girl reports hip pain that is exacerbated by weight bearing. A radiograph and biopsy specimen are shown in Figures 16a and 16b. The best course of management should be

. a steroid injection.
. curettage and bone grafting.
. radiation therapy.
. observation.
. internal fixation without a bone graft.

Correct Answer & Explanation

. curettage and bone grafting.

Explanation

The patient has a unicameral bone cyst. Because the subtrochanteric part of the femur is a high-stress region, the treatment of choice is bone curettage and grafting. Azouz EM, Karamitsos C, Reed MH, Baker L, Kozlowski K, Hoeffel JC: Types and complications of femoral neck fractures in children. Pediatr Radiol 1993;23:415-420.

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