Menu

10. Pathology and Oncology MCQs

Practice Set 320 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 6381

Topic: 10. Pathology and Oncology

A 17-year-old female presents with neck pain. Imaging reveals an expansile, multiloculated lytic lesion in the posterior elements of the C4 vertebra. Biopsy demonstrates blood-filled spaces lined by fibrous septa with multinucleated giant cells. Which of the following treatment options is most appropriate to minimize recurrence?

. Radiation therapy alone
. Simple curettage without bone grafting
. Curettage with high-speed burring and adjuvant therapy
. En bloc resection with sacrifice of the C4 nerve root
. Intravenous bisphosphonate therapy

Correct Answer & Explanation

. Curettage with high-speed burring and adjuvant therapy

Explanation

The diagnosis is an aneurysmal bone cyst (ABC), which classically occurs in the posterior elements of the spine. Extended curettage using a high-speed burr along with local adjuvants (e.g., argon beam, phenol, or cryotherapy) significantly reduces the recurrence rate compared to simple curettage.

Question 6382

Topic: Bone Tumors

A 45-year-old woman with known polyostotic fibrous dysplasia presents with new, painless soft tissue masses in her thigh musculature. MRI confirms well-circumscribed intramuscular myxomas. What is this specific clinical association called?

. Mazabraud syndrome
. McCune-Albright syndrome
. Ollier disease
. Maffucci syndrome
. Jaffe-Campanacci syndrome

Correct Answer & Explanation

. Mazabraud syndrome

Explanation

Mazabraud syndrome is a rare disorder characterized by the association of polyostotic fibrous dysplasia with single or multiple intramuscular myxomas. These myxomas are benign but are frequently located in the same anatomic region as the severely affected bones.

Question 6383

Topic: Bone Tumors

A biopsy of a metaphyseal bone lesion shows irregular, curvilinear trabeculae of woven bone lacking osteoblastic rimming, set within a moderately cellular fibrous stroma. Radiographs show a "ground-glass" appearance. What is the most likely diagnosis?

. Aneurysmal bone cyst
. Osteosarcoma
. Non-ossifying fibroma
. Fibrous dysplasia
. Chondromyxoid fibroma

Correct Answer & Explanation

. Fibrous dysplasia

Explanation

The histologic description of "Chinese character" or "alphabet soup" trabeculae of woven bone without osteoblastic rimming in a fibrous stroma is the pathognomonic feature of fibrous dysplasia. This matches the classic radiographic "ground-glass" matrix.

Question 6384

Topic: 10. Pathology and Oncology

A 16-year-old male is undergoing extended curettage of an aneurysmal bone cyst in the distal femur. The surgeon decides to use an adjuvant to reduce the risk of recurrence. Which of the following is considered a chemical adjuvant in this setting?

. Argon beam coagulation
. Liquid nitrogen
. Phenol
. Polymethylmethacrylate (PMMA)
. High-speed burr

Correct Answer & Explanation

. Phenol

Explanation

Phenol acts as a chemical cauterizing agent (adjuvant) used to induce necrosis of any microscopic tumor cells remaining after curettage. Liquid nitrogen (cryotherapy) and argon beam are physical thermal adjuvants, while a high-speed burr is mechanical.

Question 6385

Topic: 10. Pathology and Oncology

An aneurysmal bone cyst (ABC) can occasionally arise as a secondary lesion within a pre-existing primary bone tumor. Which of the following benign bone tumors is most frequently associated with secondary ABC formation?

. Osteoid osteoma
. Giant cell tumor of bone
. Osteochondroma
. Enchondroma
. Fibrous dysplasia

Correct Answer & Explanation

. Giant cell tumor of bone

Explanation

Secondary ABCs account for up to 30% of all ABCs and most commonly arise within giant cell tumors of bone, chondroblastomas, and osteoblastomas. A biopsy must carefully evaluate for an underlying primary neoplastic process to ensure proper diagnosis and treatment.

Question 6386

Topic: Bone Tumors

A 16-year-old boy presents with severe right anterior thigh pain that is predictably worse at night and dramatically relieved by NSAIDs. Imaging reveals the following characteristic finding.

What is the most characteristic biochemical feature of the central nidus in this lesion?

. High expression of alkaline phosphatase
. Excessive production of Prostaglandin E2
. Mutation in the EXT1 gene
. Translocation t(11;22)
. Elevated production of RANKL

Correct Answer & Explanation

. Excessive production of Prostaglandin E2

Explanation

Osteoid osteomas contain a central nidus that characteristically secretes high levels of Prostaglandin E2 (PGE2), causing nocturnal pain that responds to NSAIDs. The surrounding reactive sclerosis is a hallmark radiographic finding.

Question 6387

Topic: 10. Pathology and Oncology

A 14-year-old girl is diagnosed with osteosarcoma of the distal femur. Histological examination shows anaplastic spindle cells producing osteoid matrix. Which of the following genetic alterations is most commonly implicated in the pathogenesis of conventional osteosarcoma?

. t(11;22) translocation
. GNAS1 mutation
. Mutations in the p53 and Rb tumor suppressor genes
. Overexpression of the MYC oncogene
. Mutation in the EXT1 gene

Correct Answer & Explanation

. Mutations in the p53 and Rb tumor suppressor genes

Explanation

Conventional osteosarcoma is strongly linked to mutations or deletions in the p53 and Retinoblastoma (Rb) tumor suppressor genes. Inactivation of these pathways allows unregulated cellular proliferation and osteoid production by malignant cells.

Question 6388

Topic: Bone Tumors

A 13-year-old adolescent presents with a painful, rigid scoliotic curve. Imaging identifies a lesion with a radiolucent nidus on the concavity of the curve.

If surgical management is planned, what is the primary goal of the intervention?

. Spinal fusion across the scoliotic segment
. Complete en bloc resection of the involved vertebral body
. Excision or ablation of the nidus only
. Chemotherapy followed by intralesional curettage
. Radiation therapy to the affected pedicle

Correct Answer & Explanation

. Excision or ablation of the nidus only

Explanation

In spinal osteoid osteomas causing painful scoliosis, the lesion is typically found on the concavity. Successful excision or radiofrequency ablation of the nidus alone generally results in rapid relief of pain and spontaneous resolution of the scoliotic curve.

Question 6389

Topic: 10. Pathology and Oncology

A 22-year-old male with a history of Multiple Hereditary Exostoses (MHE) reports rapid enlargement and pain in a previously asymptomatic lesion on his proximal tibia. An MRI shows a cartilage cap measuring 2.5 cm in thickness. What is the most likely diagnosis?

. Enchondroma
. Chondroblastoma
. Secondary chondrosarcoma
. Osteosarcoma
. Giant cell tumor of bone

Correct Answer & Explanation

. Secondary chondrosarcoma

Explanation

Malignant transformation of an osteochondroma into a secondary chondrosarcoma should be highly suspected if the cartilage cap is thicker than 2 cm in an adult, or if the lesion becomes painful or rapidly enlarges.

Question 6390

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with fever, weight loss, and localized thigh pain. Radiographs demonstrate a permeative destructive lesion in the femoral diaphysis with an 'onion-skin' periosteal reaction. A biopsy reveals small round blue cells. Which chromosomal translocation is pathognomonic for this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is a small round blue cell tumor classically presenting in the diaphysis of long bones. It is driven by the t(11;22) translocation, creating the EWS-FLI1 fusion protein in approximately 85-90% of cases.

Question 6391

Topic: Bone Tumors

A 15-year-old boy presents with progressive right thigh pain that is notably worse at night and rapidly relieved by ibuprofen. Imaging shows a cortical lesion with a central lucent nidus and surrounding sclerosis. What is the most appropriate definitive, minimally invasive treatment for this condition?

. En bloc wide resection
. Intralesional curettage and bone grafting
. Radiofrequency ablation (RFA)
. Adjuvant radiation therapy
. Neoadjuvant chemotherapy

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. Radiofrequency ablation (RFA) under CT guidance is the gold standard minimally invasive treatment, offering high success rates and minimal morbidity.

Question 6392

Topic: 10. Pathology and Oncology

The lesion shown in the radiograph typically produces severe nocturnal pain. The central nidus of this tumor is known to produce highly elevated levels of which of the following inflammatory mediators?

. Interleukin-6
. Prostaglandin E2
. Tumor necrosis factor-alpha
. Matrix metalloproteinase-9
. Vascular endothelial growth factor

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteomas produce extremely high levels of Prostaglandin E2 (PGE2), which causes the characteristic intense night pain. This is the physiologic basis for why NSAIDs provide rapid and dramatic pain relief.

Question 6393

Topic: Bone Tumors
A 9-year-old girl is evaluated for precocious puberty and a recent pathologic proximal femur fracture. Radiographs show a 'ground-glass' expansile lesion with a 'shepherd's crook' deformity. A post-zygotic somatic mutation in which of the following genes is responsible for this condition?
. GNAS1
. EXT1
. NF1
. FGFR3
. SH3BP2

Correct Answer & Explanation

. GNAS1

Explanation

The patient has McCune-Albright syndrome, characterized by polyostotic fibrous dysplasia, precocious puberty, and café-au-lait spots. This syndrome is caused by a somatic activating mutation in the GNAS1 gene, leading to increased cAMP.

Question 6394

Topic: 10. Pathology and Oncology

A 16-year-old boy undergoes neoadjuvant chemotherapy followed by wide surgical resection for a conventional osteosarcoma of the distal femur. Which of the following histologic findings in the resected specimen is the single most important prognostic factor for long-term survival?

. Percentage of tumor necrosis
. Number of mitotic figures per high-power field
. Presence of multinucleated giant cells
. Amount of chondroid matrix produced
. Lymphocytic infiltration at the tumor margins

Correct Answer & Explanation

. Percentage of tumor necrosis

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy (evaluated by the Huvos grading system) is the most critical prognostic indicator. Greater than 90% necrosis indicates a favorable response and better long-term survival.

Question 6395

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a diaphyseal femur lesion exhibiting a 'moth-eaten' appearance and periosteal 'onion-skinning'. Biopsy reveals sheets of uniform small round blue cells. Which of the following chromosomal translocations is diagnostic for this malignancy?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and histologic description is classic for Ewing sarcoma. The t(11;22)(q24;q12) translocation, resulting in the EWS-FLI1 fusion protein, is found in approximately 85% of Ewing sarcoma cases.

Question 6396

Topic: Bone Tumors

The radiograph demonstrates a typical osteoid osteoma. If a histopathologically identical lesion presented in the posterior elements of the spine, measured 3.0 cm in diameter, and caused progressive non-structural scoliosis without classic nocturnal pain, what would be the most likely diagnosis?

. Osteoid osteoma
. Osteosarcoma
. Osteoblastoma
. Aneurysmal bone cyst
. Chondroblastoma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Osteoblastomas are histologically indistinguishable from osteoid osteomas but are distinguished clinically by their larger size (>2 cm), predilection for the posterior elements of the spine, and less predictable response to NSAIDs.

Question 6397

Topic: Bone Tumors

A 15-year-old male presents with dull, aching thigh pain that is predictably worse at night and dramatically relieved by NSAIDs.

Based on the typical clinical and radiographic presentation shown, what is the most likely diagnosis?

. Ewing sarcoma
. Osteoid osteoma
. Chondroblastoma
. Osteoblastoma
. Non-ossifying fibroma

Correct Answer & Explanation

. Osteoid osteoma

Explanation

The classic presentation of night pain relieved by NSAIDs combined with an imaging finding of a radiolucent nidus surrounded by dense reactive sclerosis is diagnostic for osteoid osteoma. Prostaglandin production by the nidus is responsible for the characteristic pain pattern.

Question 6398

Topic: 10. Pathology and Oncology

A 14-year-old male is diagnosed with high-grade conventional osteosarcoma of the distal femur. After completing neoadjuvant chemotherapy, he undergoes wide surgical resection. Which of the following histological findings in the resected specimen is the most critical prognostic factor for his overall survival?

. Initial tumor volume
. Presence of chondroblastic differentiation
. Percentage of tumor necrosis
. Density of spindle cell stroma
. Extent of periosteal reaction

Correct Answer & Explanation

. Percentage of tumor necrosis

Explanation

The percentage of tumor necrosis in response to neoadjuvant chemotherapy (typically using the Huvos grading system) is the single most important histologic prognostic indicator for osteosarcoma. Greater than 90% necrosis indicates a good response and correlates with improved survival.

Question 6399

Topic: 10. Pathology and Oncology

A 30-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion in the proximal tibia extending to the subchondral bone. Biopsy confirms Giant Cell Tumor of Bone (GCTB). Prior to planned intralesional curettage, the multidisciplinary tumor board recommends medical therapy to consolidate the tumor margins. Which agent is most appropriate?

. Imatinib
. Denosumab
. Methotrexate
. Doxorubicin
. Zoledronic acid

Correct Answer & Explanation

. Denosumab

Explanation

Denosumab, a monoclonal antibody against RANKL, inhibits osteoclast-like giant cell formation, leading to tumor necrosis and peripheral ossification of the tumor margin. It is widely used to facilitate joint-sparing curettage in challenging or aggressive GCTB cases.

Question 6400

Topic: 10. Pathology and Oncology

A 60-year-old male with a history of renal cell carcinoma presents with impending pathologic fracture of the subtrochanteric femur (Mirels score 10). Surgical stabilization with an intramedullary nail is planned. What critical preoperative intervention must be performed to minimize catastrophic intraoperative complications?

. Systemic chemotherapy
. Preoperative embolization
. Local radiation therapy
. Prophylactic bisphosphonate infusion
. Core needle biopsy

Correct Answer & Explanation

. Preoperative embolization

Explanation

Renal cell carcinoma and thyroid carcinoma bone metastases are notoriously hypervascular. Preoperative angiographic embolization (typically within 24-48 hours prior to surgery) is essential to minimize the risk of massive, uncontrollable intraoperative hemorrhage.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page