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10. Pathology and Oncology MCQs

Practice Set 24 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 461

Topic: 10. Pathology and Oncology

A 65-year-old man presents with chronic, progressively worsening thigh pain. Radiographs of the femur demonstrate a destructive diaphyseal lesion with stippled, 'popcorn-like' calcifications and endosteal scalloping greater than 2/3 of the cortical thickness. Biopsy reveals atypical chondrocytes in a hyaline cartilage matrix. What is the most appropriate management?

. Neoadjuvant chemotherapy followed by wide surgical resection
. Wide surgical resection alone
. Intralesional curettage with phenol adjuvant and bone grafting
. Primary radiation therapy
. Preoperative radiation followed by wide surgical resection

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

The clinical and radiographic findings are classic for a conventional chondrosarcoma. Conventional chondrosarcomas are notoriously resistant to both chemotherapy and radiation, making wide surgical resection the mainstay of treatment.

Question 462

Topic: 10. Pathology and Oncology

The most common cause of a pediatric pathologic fracture of the proximal humerus is:

. Osteochondroma
. Osteogenic sarcoma
. Unicameral bone cyst
. Codman tumor (chondroblastoma)
. Fibrous cortical defect

Correct Answer & Explanation

. Unicameral bone cyst

Explanation

The most common cause of a pathologic fracture of the proximal humerus is unicameral bone cyst. This fluid-filled cyst expands and weakens the humerus, often causing a fracture as its first evidence of existence. Although the proximal humerus is one of the more common sites of their occurrence, osteochondromas do not significantly weaken the humerus. Osteogenic sarcoma is a relatively rare bone tumor, and it does not weaken the bone until it is at an advanced stage. Codman tumor (chondroblastoma) is classically described in the proximal humerus, it is rare and typically epiphyseal in location, and does not appreciably weaken the bone. Although fibrous cortical defects are common tumors, they rarely present in this way.

Question 463

Topic: Bone Tumors

C ongenital pseudarthrosis of the clavicle occurs most commonly on which side:

. Bilateral
. Right
. Left
. The side more involved with fibrous dysplasia
. The side with the proximal focal femoral dysplasia

Correct Answer & Explanation

. Right

Explanation

Ninety percent of cases are noted on the right side. Ten percent of cases are bilateral and have been associated with bilateral cervical ribs. Only a few cases of left-sided pseudarthrosis have been described and have been associated with dextrocardia. Only <5% of cases of congenital pseudarthrosis are on the left. Congenital pseudarthrosis is not related to fibrous dysplasia. Congenital pseudarthrosis is not related to proximal focal femoral dysplasia.

Question 464

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a destructive diaphyseal bone lesion exhibiting an 'onion-skin' periosteal reaction. Genetic testing reveals a t(11;22) chromosomal translocation. Which of the following is the specific fusion protein associated with this tumor?

. EWS-FLI1
. SYT-SSX
. TLS-CHOP
. PAX3-FKHR
. BCR-ABL

Correct Answer & Explanation

. EWS-FLI1

Explanation

The clinical and radiographic presentation is highly characteristic of Ewing sarcoma. The t(11;22) translocation results in the EWS-FLI1 fusion protein, which is found in over 85% of Ewing sarcoma cases.

Question 465

Topic: Bone Tumors

A 9-year-old boy presents with mild right arm pain after a minor fall. Radiographs are obtained.

Assuming the radiograph demonstrates a central, completely lytic metaphyseal lesion with a 'fallen leaf' sign, what is the most appropriate initial management?

. Wide en bloc resection
. Neoadjuvant chemotherapy followed by limb salvage
. Observation alone with no intervention
. Aspiration and injection of methylprednisolone
. Amputation

Correct Answer & Explanation

. Aspiration and injection of methylprednisolone

Explanation

A central, lytic metaphyseal lesion with a 'fallen leaf' sign is pathognomonic for a Unicameral Bone Cyst (UBC). The initial treatment of choice for symptomatic or fracture-prone UBCs is aspiration and corticosteroid injection.

Question 466

Topic: 10. Pathology and Oncology

Which of the following benign bone tumors is characteristically located within the epiphysis of long bones in skeletally immature patients?

. Chondroblastoma
. Unicameral bone cyst
. Osteochondroma
. Non-ossifying fibroma
. Enchondroma

Correct Answer & Explanation

. Chondroblastoma

Explanation

Chondroblastoma is a rare, benign cartilaginous tumor that classically presents in the epiphysis or apophysis of long bones in children and adolescents before physeal closure.

Question 467

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with knee pain. Radiographs show the lesion seen in the image.

Assuming a malignant primary bone tumor, what is the most likely diagnosis given a 'sunburst' periosteal reaction in the metaphysis?

. Osteosarcoma
. Ewing sarcoma
. Osteochondroma
. Non-ossifying fibroma
. Chondroblastoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma often presents in the metaphysis of long bones in adolescents with a 'sunburst' periosteal reaction and Codman's triangle. Ewing sarcoma typically affects the diaphysis and has an 'onion skin' appearance.

Question 468

Topic: Bone Tumors

A 65-year-old man presents with severe back pain and anemia. A skeletal survey shows multiple lytic 'punched-out' lesions in the skull and spine. Which of the following laboratory findings is most specific for this condition?

. Elevated alkaline phosphatase
. Monoclonal spike on serum protein electrophoresis
. Decreased serum calcium
. Elevated C-reactive protein
. Positive HLA-B27

Correct Answer & Explanation

. Monoclonal spike on serum protein electrophoresis

Explanation

Multiple myeloma classically presents with lytic bone lesions, hypercalcemia, anemia, and renal involvement. A monoclonal M-protein spike on serum or urine protein electrophoresis is highly characteristic.

Question 469

Topic: 10. Pathology and Oncology

A 6-year-old boy with delayed motor milestones routinely uses his hands to push on his legs to stand up from the floor. Muscle biopsy shows absent dystrophin. What is the typical inheritance pattern of this disease?

. Autosomal dominant
. Autosomal recessive
. X-linked recessive
. X-linked dominant
. Mitochondrial

Correct Answer & Explanation

. X-linked recessive

Explanation

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disorder caused by nonsense or frameshift mutations in the dystrophin gene. The described Gowers' sign is a classic clinical manifestation of the resultant proximal muscle weakness.

Question 470

Topic: Soft Tissue Tumors & Metastasis

Criteria for diagnosis of neurofibromatosis 1 (NF1) include all the signs below except:

. Cafa-au-lait spots
. Lisch nodules
. Axillary or inguinal freckling
. Neurologic deficit
. A distinctive osseous lesion

Correct Answer & Explanation

. Neurologic deficit

Explanation

While neurologic deficit may be associated with some of the spinal deformities in neurofibromatosis 1 (NF1), it does not constitute one of the diagnostic criteria. The diagnostic criteria for NF1 were established by The C onsensus Development Conference on Neurofibromatosis at the National Institutes of Health in 1987: Six or more cafa-au-lait spots, at least 15 mm in diameter in adults and 5 mm in children. Two or more neurofibromas of any type or one plexiform neurofibroma. Freckling in the axillae or inguinal regions (Crowe sign). Two or more iris hamartomas (Lisch nodules). A distinctive osseous lesion, such as sphenoid dysplasia or thinning of long bone cortex, with or without pseudarthrosis. A first-degree relative with NF1 by the above criteria.

Question 471

Topic: Soft Tissue Tumors & Metastasis

The origin of "dumbbell lesions" found in radiographs of patients with neurofibromatosis 1 (NF1) is:

. Flattening of the intervertebral disk with enlargement on the lateral borders
. Thinning of the midshaft of the tibia giving this bone the appearance of a dumbbell
. Neurofibromas or meningoceles that protrude through spinal foramina
. Subperiostial bone proliferation
. Two closely spaced cysts within a bone

Correct Answer & Explanation

. Neurofibromas or meningoceles that protrude through spinal foramina

Explanation

Intraspinal lesions, such as neurofibromas and meningoceles, that protrude through the neural foramina give the radiologic appearance of a "dumbbell lesion." Flattening of the intervertebral disk with enlargement of the lateral borders is not a feature of neurofibromatosis 1 (NF1). Tibial dysplasia seen in patients with NF1 lead to anterolateral bowing and does not give the appearance of a dumbbell. While subperiostial bone proliferation is seen in NF1, it does not give the appearance of a dumbbell. Bone cysts are a recognized complication of NF1, but are not the origin of the dumbbell lesions seen on radiographs.

Question 472

Topic: 10. Pathology and Oncology

Which ancillary test is not helpful in the diagnosis of C harcot-Marie-Tooth disease (C MT):

. Electromyography (EMG)
. Nerve conduction velocity (NC V)
. Nerve biopsy
. Muscle biopsy
. Muscle enzymes

Correct Answer & Explanation

. Muscle enzymes

Explanation

Charcot-Marie-Tooth disease (C MT) is a neuropathic process resulting in muscle atrophy, therefore, muscle enzyme studies will not be helpful. Electromyography (EMG) will confirm the diagnosis by displaying increased amplitude and duration of signals, both of which are indicative of a neuropathic process. Nerve conduction velocity (NC V) will also confirm the diagnosis by displaying decreased motor and sensory conduction velocities. Nerve biopsy can be helpful by showing loss of myelinated fibers and fibrosis. Muscle biopsy will show diffuse atrophy, fibrosis, and adipose tissue within muscle.

Question 473

Topic: 10. Pathology and Oncology
What is the molecular disturbance responsible for the development of homocystinuria?
. Translocation of chromosome 11 and 22
. Accumulation of cerebrosides in the reticuloendothelial system
. Methionine deficiency
. Deficiency of cystathionine β-synthase
. Pyridoxine deficiency

Correct Answer & Explanation

. Deficiency of cystathionine β-synthase

Explanation

The metabolic disturbance responsible for homocystinuria is a deficiency of cystathionine β-synthase. A translocation of chromosome 11 and 22 is a feature of some patients with Ewing's tumor. Accumulation of cerebrosides in the reticuloendothelial system is found in Gaucher's disease. Methionine is present in excessive quantities in homocystinuria because it cannot be converted to cysteine due to the deficiency of cystathionine β-synthase. Pyridoxine deficiency is a secondary feature of the disorder, but it is not the primary cause.

Question 474

Topic: 10. Pathology and Oncology

A 14-year-old male presents with a diaphyseal femur lesion showing a permeative pattern and "onion-skin" periosteal reaction on radiographs. Which chromosomal translocation is most characteristic of this suspected malignant bone tumor?

. t(11;22)(q24;q12)
. t(X;18)(p11;q11)
. t(9;22)(q34;q11)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)

Correct Answer & Explanation

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

Explanation

The clinical and radiographic presentation is classic for Ewing Sarcoma. The hallmark genetic mutation is the t(11;22)(q24;q12) translocation, which forms the EWS-FLI1 fusion protein.

Question 475

Topic: Bone Tumors

A 19-year-old male complains of severe night pain in his right tibial diaphysis that is consistently and completely relieved by NSAIDs. Radiographs demonstrate a 1 cm radiolucent nidus surrounded by reactive sclerosis. If conservative management fails, what is the treatment of choice?

. En bloc resection
. Radiofrequency ablation (RFA)
. Radiation therapy
. Chemotherapy
. Amputation

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. If medical management with NSAIDs fails or is poorly tolerated, percutaneous Radiofrequency Ablation (RFA) is the definitive, minimally invasive treatment of choice.

Question 476

Topic: 10. Pathology and Oncology

A 16-year-old male is undergoing treatment for osteosarcoma of the distal femur. Following preoperative neoadjuvant chemotherapy, surgical resection is performed. Which of the following factors provides the most significant prognostic value for his overall survival?

. The initial size of the primary tumor
. The patient's age at the time of diagnosis
. The percentage of histologic tumor necrosis in the resected specimen
. The preoperative serum alkaline phosphatase level
. The exact anatomic location of the lesion within the metaphysis

Correct Answer & Explanation

. The percentage of histologic tumor necrosis in the resected specimen

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the most reliable prognostic indicator for survival in osteosarcoma. A good response is defined as greater than 90% tumor necrosis in the resected specimen.

Question 477

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with knee pain and a palpable mass in the distal femur. Biopsy confirms conventional high-grade intramedullary osteosarcoma. What is the most appropriate, evidence-based treatment sequence?

. Primary amputation followed by radiation therapy
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Wide surgical resection alone
. Radiation therapy followed by wide surgical resection
. Neoadjuvant radiation, intralesional curettage, and cementation

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

The standard of care for conventional high-grade osteosarcoma is neoadjuvant (preoperative) chemotherapy, followed by wide surgical resection, and concluding with adjuvant (postoperative) chemotherapy. Osteosarcoma is highly radioresistant, making radiation therapy generally ineffective for primary local control.

Question 478

Topic: 10. Pathology and Oncology

Giant cell tumor of tendon sheath commonly occurs in which of the following age groups:

. Infants (age 0-1 year)
. Age 1-10 years
. Age 10-20 years
. Age 30-40 years
. Age 60-70 years

Correct Answer & Explanation

. Age 30-40 years

Explanation

Giant cell tumor of tendon sheath is most commonly found in patients in the fourth through sixth decades; therefore, age 30-40 years is the most appropriate answer choice.

Question 479

Topic: 10. Pathology and Oncology

Which of the following clinical features is common in giant cell tumor of tendon sheath:

. Transillumination
. Erythematous
. Fluctuates in size
. Presents with rapid change in size
. Painless

Correct Answer & Explanation

. Painless

Explanation

Giant cell tumor of tendon sheath is painless. Giant cell tumor of tendon sheath does not transilluminate, as ganglion cyst does. No overlying skin color changes occur. Giant cell tumor of tendon sheath only increases in size and does not fluctuate like a ganglion cyst; it does not present with a rapid increase in size.

Question 480

Topic: 10. Pathology and Oncology

After plain radiographs of giant cell tumor of tendon sheath are obtained, the following imaging study should be obtained:

. C omputed tomography scan
. Ultrasound
. Magnetic resonance image
. Angiogram
. Bone scan

Correct Answer & Explanation

. Magnetic resonance image

Explanation

Magnetic resonance imaging provides anatomic detail of the soft tissue mass, helps generate a differential diagnosis, and determines if the mass is unifocal or multifocal and where it originates. Giant cell tumor of tendon sheath is a soft-tissue tumor. Computed tomography is best for bone-based tumors. Ultrasound helps localize lesions but does not provide anatomic detail to help determine the type of mass. Although angiograms are useful for vascular tumors such as renal cell carcinoma or arteriovenous malformations, they are not necessary in the evaluation of a soft tissue mass in the hand with features suggestive of giant cell tumor of tendon sheath. A bone scan is useful when malignant bone tumors are suspected rather than benign soft tissue masses.

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