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10. Pathology and Oncology MCQs

Practice Set 1 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 1

Topic: Bone Tumors

Which of the following is characteristic of osteosarcoma on imaging?

. Sunburst appearance
. Lytic lesion with sharp margins
. Purely sclerotic lesion
. Geographic destruction pattern
. Cortical thickening without periosteal reaction

Correct Answer & Explanation

. Sunburst appearance

Explanation

Osteosarcoma is often characterized by an aggressive periosteal reaction on X-ray, including a "sunburst" or "Codman's triangle" appearance, indicative of rapid bone formation and destruction.

Question 2

Topic: Bone Tumors

Which bone is most commonly affected by osteosarcoma in adolescents?

. Humerus
. Radius
. Vertebrae
. Fibula
. Femur

Correct Answer & Explanation

. Femur

Explanation

Osteosarcoma commonly affects the metaphysis of long bones, with the distal femur being the most frequent site, followed by the proximal tibia and proximal humerus.

Question 3

Topic: 10. Pathology and Oncology

What is the most common primary malignant bone tumor in children and young adults?

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

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents, typically occurring during growth spurts.

Question 4

Topic: 10. Pathology and Oncology

What is the most common primary benign bone tumor?

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

Correct Answer & Explanation

. Osteochondroma

Explanation

Osteochondroma is the most common primary benign bone tumor, typically appearing as an outgrowth of cartilage-capped bone near the growth plate.

Question 5

Topic: Bone Tumors

The differential diagnosis for patients presenting with radiographs consistent with myositis ossificans includes all of the following except:

. Osteosarcoma
. Osteochondroma
. Osteomyelitis
. C hondrosarcoma
. Rhabdomyosarcoma

Correct Answer & Explanation

. Rhabdomyosarcoma

Explanation

When evaluating a patient with calcification or ossification in abnormal regions, a thorough differential including all of the mentioned conditions should be considered. Osteochondromas will typically have an intramedullary canal continuous with the adjacent bone. Osteomyelitis will sometimes have associated constitutional symptoms. Osteosarcoma will typically have a radiodense center as opposed to the radiodense periphery of mature myositis ossificans. Chondrosarcoma can be confused with myositis ossificans.

Question 6

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful, enlarging mass in his diaphyseal femur. Biopsy reveals uniform small round blue cells. Genetic analysis demonstrates a t(11;22) chromosomal translocation. Which fusion protein is characteristic of this tumor?

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

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is characterized histologically by small round blue cells and genetically by the t(11;22) translocation. This specific chromosomal abnormality results in the oncogenic EWS-FLI1 fusion protein.

Question 7

Topic: 10. Pathology and Oncology

A 12-year-old boy presents with a destructive diaphyseal lesion of the femur. Biopsy reveals small round blue cells, and molecular testing shows a t(11;22) chromosomal translocation. Which fusion protein is characteristic of this tumor?

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

Correct Answer & Explanation

. EWS-FLI1

Explanation

The clinical and histologic picture describes Ewing sarcoma, which is characterized by the t(11;22) translocation. This chromosomal abnormality results in the oncogenic EWS-FLI1 fusion protein.

Question 8

Topic: 10. Pathology and Oncology

A 16-year-old boy presents with a destructive diaphyseal lesion of the femur with an "onion skin" periosteal reaction. A biopsy reveals small blue round cells. Which of the following genetic translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. The most common genetic abnormality associated with Ewing sarcoma is the t(11;22) translocation, which forms the EWS-FLI1 fusion protein.

Question 9

Topic: 10. Pathology and Oncology

In evaluating a patient with scapulothoracic crepitus (snapping scapula syndrome), a palpable mass is felt at the superomedial angle of the scapula. What is the most common benign bone tumor responsible for this presentation?

. Enchondroma
. Osteochondroma
. Chondroblastoma
. Osteoid osteoma
. Aneurysmal bone cyst

Correct Answer & Explanation

. Osteochondroma

Explanation

Osteochondroma is the most common benign bone tumor of the scapula and can cause snapping scapula syndrome by physically rubbing against the rib cage during scapulothoracic motion.

Question 10

Topic: 10. Pathology and Oncology

A 35-year-old female presents with recurrent, spontaneous knee effusions and a diffuse, boggy synovitis. MRI reveals a thickened synovium with a prominent 'blooming artifact' on gradient-echo sequences. What is the most likely diagnosis?

. Rheumatoid arthritis
. Lyme arthritis
. Pigmented villonodular synovitis (TGCT)
. Synovial chondromatosis
. Tuberculous arthritis

Correct Answer & Explanation

. Pigmented villonodular synovitis (TGCT)

Explanation

Pigmented villonodular synovitis (PVNS), also known as tenosynovial giant cell tumor (TGCT), is characterized by repetitive intra-articular bleeding. The hemosiderin deposition within the hypertrophic synovium causes a classic blooming artifact on gradient-echo MRI.

Question 11

Topic: 10. Pathology and Oncology
What is the prevalence of Schmorl's nodes in the general population?
. 3%
. 7%
. 10%
. 15%
. 19%

Correct Answer & Explanation

. 10%

Explanation

Approximately 10% of the population has Schmorl's nodes, which are often completely benign.

Question 12

Topic: 10. Pathology and Oncology

In a 3-week-old infant presenting with a palpable, firm mass in the sternocleidomastoid muscle and a clinical diagnosis of congenital muscular torticollis, what is the expected natural history of this sternomastoid tumor?

. It progressively enlarges requiring urgent surgical excision
. It typically calcifies by age 2 causing permanent restriction
. It resolves spontaneously by 4 to 8 months of age
. It undergoes malignant transformation in 1% of cases
. It remains stable in size into adulthood

Correct Answer & Explanation

. It resolves spontaneously by 4 to 8 months of age

Explanation

A sternocleidomastoid tumor of infancy typically becomes palpable at 2 to 3 weeks of age, peaks in size at 1 to 2 months, and resolves spontaneously by 4 to 8 months with conservative stretching.

Question 13

Topic: 10. Pathology and Oncology
A 7-year-old boy presents with localized severe back pain. Radiographs reveal a completely flattened vertebral body (vertebra plana) in the thoracic spine with preserved adjacent disc spaces. What is the most likely underlying etiology?
. Tuberculosis (Pott's disease)
. Eosinophilic granuloma
. Aneurysmal bone cyst
. Pyogenic osteomyelitis
. Ewing sarcoma

Correct Answer & Explanation

. Eosinophilic granuloma

Explanation

Eosinophilic granuloma (Langerhans cell histiocytosis) in the spine classically causes symmetrical collapse of the vertebral body, resulting in 'vertebra plana' (Calvรฉ's disease). The adjacent intervertebral disc spaces are characteristically preserved.

Question 14

Topic: 10. Pathology and Oncology

A 60-year-old man with a history of renal cell carcinoma presents with progressive lower extremity weakness. Imaging shows a destructive metastatic lesion at T8 causing spinal cord compression. Prior to surgical decompression and stabilization, what is the most important preparatory step?

. Initiation of systemic chemotherapy
. Preoperative radiation therapy
. Preoperative selective arterial embolization
. Intravenous bisphosphonate infusion
. Percutaneous needle biopsy

Correct Answer & Explanation

. Preoperative selective arterial embolization

Explanation

Renal cell carcinoma and thyroid carcinoma bone metastases are notoriously hypervascular. Preoperative selective arterial embolization is highly recommended to significantly reduce massive intraoperative blood loss during decompression.

Question 15

Topic: 10. Pathology and Oncology

A 50-year-old intravenous drug user presents with chronic back pain and low-grade fevers. MRI shows T1 hypointensity and T2 hyperintensity in the L3 and L4 vertebral bodies with involvement of the intervening disc space. Which of the following is the best initial step for definitive diagnosis?

. Empiric broad-spectrum antibiotics
. CT-guided needle biopsy
. Open surgical debridement
. Bone scan
. ESR and CRP alone

Correct Answer & Explanation

. CT-guided needle biopsy

Explanation

CT-guided needle biopsy is the most appropriate initial step to obtain a definitive microbiological diagnosis. This should be performed before initiating targeted antibiotic therapy in suspected pyogenic spondylodiscitis.

Question 16

Topic: 10. Pathology and Oncology

The proper treatment of a vertebral osteoblastoma includes:

. Chemotherapy
. En-bloc resection
. Marginal excision/curettage of the tumor
. Radiation
. Radiofrequency ablation

Correct Answer & Explanation

. Marginal excision/curettage of the tumor

Explanation

Treatment of spinal osteoblastomas usually consists of marginal excision or curettage of the tumor. Local recurrence rates of up to 10% have been observed from some osteoblastomas, however, malignant degeneration is rare. There is no role for radiation or chemotherapy. Radiofrequency ablation has been used successfully for the treatment of osteoid osteomas, but not osteoblastomas.C orrect Answer: Marginal excision/curettage of the tumor

Question 17

Topic: Bone Tumors

Typical histologic features of an osteoblastoma include all of the following except:

. Vascularized spindle cell stroma
. Nidus composed of haphazardly arranged network of osteoid trabeculae
. Occasional areas of aneurysmal bone cyst formation
. Osteoblasts rimming the trabeculae
. C hondrocytes arranged in a zonal pattern

Correct Answer & Explanation

. C hondrocytes arranged in a zonal pattern

Explanation

Histologically osteoblastoma is similar to an osteoid osteoma; its features include: Irregular osteoid arranged haphazardly with rimming by round osteoblasts Loose fibrovascular connective tissue between trabeculae Osteoblasts rimming the trabeculae Vascularized spindle cell stroma Areas of aneurysmal bone cyst formation can be seen

Question 18

Topic: 10. Pathology and Oncology

Primary spinal tumors account for:

. 0.4% of all tumors and 1% of all bone tumors
. 0.4 % of all tumors and 10% of all bone tumors
. 0.4 % of all tumors and 25% of all bone tumors
. 0.04% of all tumors and 10% of all bone tumors
. 0.04 % of all tumors and 25% of all bone tumors

Correct Answer & Explanation

. 0.04% of all tumors and 10% of all bone tumors

Explanation

Neoplasms of the spine can be broadly categorized into metastatic tumors and primary tumors. Primary spinal tumors are rare and account for 0.04% of all tumors and 10% of all bone tumors.

Question 19

Topic: 10. Pathology and Oncology
Pain is the most common complaint in patients presenting with a primary spine tumor and is present in which percentage of patients?
. 55%
. 65%
. 75%
. 85%
. 95%

Correct Answer & Explanation

. 85%

Explanation

Pain is the most common complaint in patients presenting with a primary spine tumor, present in up to 85% of patients. It is typically localized to the site of the lesion but can be radicular. It is characterized as progressive, gradual in onset, worse at night, and non-mechanical. Weakness can be seen in up to 42% of patients, and a mass is evident in up to 16% of patients.

Question 20

Topic: 10. Pathology and Oncology

What percentage of trabecular bone must be destroyed before changes can be seen on plain radiographs:

. 20% to 40%
. 30% to 50%
. 40% to 60%
. 60% to 80%
. 70% to 90%

Correct Answer & Explanation

. 30% to 50%

Explanation

I. Imaging studies used most frequently in the diagnosis of primary spine tumors include: A. Plain radiographs 1. Initial imaging study 2. Recommended for any patient with prolonged back pain (>6 weeks) 3. Identify 30% to 70% of spine tumors at presentation 4. Early lesions difficult to detect because 30% to 50% of trabecular bone must be destroyed before changes can be seen 5. Absence of the pedicle is usually the earliest radiographic sign of vertebral 6. Cortical bone loss easier to detect than destruction of trabecular bone 7. "Winking owl" sign 8. Disk space generally preserved 9. Geographic lesions with well-circumscribed borders suggest a benign tumor 10. Permeative lesions suggest a malignant tumor B. Bone scan 1. Technetium (Tc)-99m 2. C an identify lesions 3 to 18 months before plain radiographs 3. Sensitivity 74%, specificity 81% 4. False negative in up to 60% of patients with multiple myeloma 5. Single photon emission computerized tomography scan can improve both sensitivity (87%) and specificity (91%) 6. When used in combination with gallium scanning, Tc-99 bone scan can help to differentiate between tumors and infections C . Computed tomography/myelography 1. Best test to determine extent of bony destruction 2. Important in surgical planning 3. Myelography usually used only when magnetic resonance imaging (MRI) not possible (danger of complete myelographic block) D. MRI 1. Modality of choice in evaluating tumors of the spine 2. Noninvasive 3. Allows direct visualization of entire spinal cord 4. Visualization of soft tissues 5. Sensitivity 92%, specificity 90% 6. Additional lesions in 20% to 24%, and 10% will have multiple levels of cord compression

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