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Bone Tumors MCQs

Practice Set 13 of 52

This practice set contains high-yield board review questions covering key concepts in Bone Tumors. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 241

Topic: Bone Tumors

Nonossifying fibroma

. Cortical thickening in the region of the lesion
. Erosive metaphyseal lesion with loss of cortical integrity
. Normal bony anatomy on radiographs
. Diffuse articular erosion with loss of joint space
. Round, expansive, well-circumscribed metaphyseal lesion with thinning of the cortex
. Eccentric well-circumscribed metaphyseal lesion with a scalloped border

Correct Answer & Explanation

. Cortical thickening in the region of the lesion

Explanation

DISCUSSIONEarly osteomyelitis and septic arthritis appear as normal bony anatomy on radiographs, with perhaps only soft-tissue swelling seen. Radiographic changes with metaphyseal erosion appear in a delayed fashion, often after 7 or more days in indolent infections, but may present earlier in association with virulent infections such as methicillin-resistant Staphylococcus aureus. Osteoid osteoma has a radiolucent small nidus that may be difficult to see on radiograph; however, chronic cases cause marked cortical hypertrophy. Unicameral bone cysts are expansile metaphyseal lesions that are never wider than the physis. They are symmetric, well circumscribed, and can have cortical thinning. When fractures through the cyst arepresent, the fallen leaf sign is visible as cortical fragments fall to the bottom of the cyst. Nonossifying fibromas are eccentric metaphyseal lesions with scalloped borders.

Question 242

Topic: Bone Tumors

A 62-year-old woman reports diffuse aches and pains of the hip and pelvis. She denies any significant trauma but does have a history of chronic anemia. Figure 17a shows a radiograph of the pelvis, and Figures 17b and 17c show T 2 -weighted MRI scans. What is the most likely diagnosis?

. Chondrosarcoma
. Diffuse fibrous dysplasia
. Multiple myeloma
. Osteoporosis
. Bone infarcts

Correct Answer & Explanation

. Chondrosarcoma

Explanation

DISCUSSION: The radiograph reveals diffuse osteopenia and areas in the proximal femora that are moth-eaten in appearance.  The extent of the marrow-replacing process is evident on the MRI scans, which reveal signal abnormality throughout the entire pelvis and both proximal femora.  This represents a marrow-packing process, of which multiple myeloma is the best choice.  This diagnosis is also supported by the anemia noted on the patient’s history.  Metastatic carcinoma and lymphoma also may have a similar presentation.REFERENCE: Resnick D (ed): Diagnosis of Bone and Joint Disorders.  Philadelphia, PA,WB Saunders, 2002, pp 2189-2216.

Question 243

Topic: Bone Tumors

Which of the following best describes the function of the notochord?

. The notochord becomes the medulla oblongata in adults.
. The notochord induces tissues that eventually become the vertebral column.
. The notochord disappears with ossification of vertebral bodies.
. The notochord develops into the ring apophysis.
. Remnants of the notochord are often found in the coccyx.

Correct Answer & Explanation

. The notochord becomes the medulla oblongata in adults.

Explanation

DISCUSSION: The notochord is the anatomic structure that defines the phylum Chordata.  The notochord plays a fundamental role in the development of the skeleton, and it exists only for a short period of time.  During its temporary existence, the notochord serves as a transient axis of support, provides for the initial axis of orientation of the developing embryo, and most importantly, plays a vital role in the induction of the tissues that eventually form the vertebral column.REFERENCE: Rosenberg A: Embryology of the skull base and vertebral column, in Harsh G (ed): Chordomas and Chondrosarcomas of the Skull Base and Spine.  New York, NY, Thieme, 2003, pp 3-8.

Question 244

Topic: Bone Tumors
A 19-year-old woman reports persistent neck pain for 2 years. Pain is relieved with aspirin. A bone scan shows intense uptake in the superior, posterior portion of the C3 vertebral body. A sagittal CT reconstruction is shown in Figure 5. Treatment should consist of
. radiation therapy.
. en bloc excision.
. posterior fusion at C2-C3 with instrumentation.
. CT-guided aspiration followed by IV antibiotics.
. radiofrequency ablation.

Correct Answer & Explanation

. en bloc excision.

Explanation

DISCUSSION: The CT scan shows an osteoblastic nidus pathognomonic for an osteoid osteoma. Surgical treatment should include an en bloc excision of the lesion. Surgical treatment is not mandatory because the lesion often becomes asymptomatic over time. This lesion is not amenable to radiofrequency ablation due to its proximity to the spinal cord. A complete corpectomy is not necessary to adequately resect the lesion, as only the nidus needs to be removed. Radiation therapy and antibiotics are not appropriate treatments for an osteoid osteoma. Posterior C2-C3 fusion will not address the pathology. REFERENCES: Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 351-366. Hadjipavlou AG, Lander PH, Marchesi D, et al: Minimally invasive surgery for ablation of osteoid osteoma of the spine. Spine 2003;28:E472-E477.

Question 245

Topic: Bone Tumors
A 31-year-old woman has a history of a painful ankle that has failed to respond to conservative management. She has associated night pain that is relieved with nonsteroidal anti-inflammatory drugs. MRI and technetium Tc 99m scans are consistent with an osteoid osteoma. Management should now consist of:
. Curettage or en bloc resection.
. Allograft limb salvage.
. Injection with 5% phenol.
. Radiation therapy.
. Hormonal therapy.

Correct Answer & Explanation

. Curettage or en bloc resection.

Explanation

DISCUSSION: Surgical curettage or en bloc resection is the treatment of choice for osteoid osteoma. Night pain and relief of symptoms with nonsteroidal anti-inflammatory drugs are classic findings for osteoid osteoma. REFERENCES: Donley BG, Philbin T, Rosenberg GA, Schils JP, Recht M: Percutaneous CT guided resection of osteoid osteoma of the tibial plafond. Foot Ankle Int 2000;21:596-598. Kenzora JE, Abrams RC: Problems encountered in the diagnosis and treatment of osteoid osteoma of the talus. Foot Ankle 1981;2:172-178. Shereff MJ, Cullivan WT, Johnson KA: Osteoid-osteoma of the foot. J Bone Joint Surg Am 1983;65:638-641.

Question 246

Topic: Bone Tumors
Figure 40 shows the radiograph of a 30-year-old woman who has a painful elbow. Examination reveals a deformed skull, multiple cafe-au-lait spots, and bone deformities. What is the most likely diagnosis?
. McCune-Albright syndrome
. Neurofibromatosis, type I (NF-1)
. Neurofibromatosis, type II (NF-2)
. Paget’s disease
. Ollier’s disease

Correct Answer & Explanation

. McCune-Albright syndrome

Explanation

Findings in patients with McCune-Albright syndrome include polyostotic fibrous dysplasia, multiple cafe-au-lait spots, and precocious puberty. The bone changes in NF-1 resemble nonossifying fibromas, not fibrous dysplasia. NF-2 has little bony change with typical ocular abnormalities. Paget’s disease occurs in older individuals and does not present with cafe-au-lait spots. Ollier’s disease (multiple enchondromatosis) may show bone changes but not the other findings.

Question 247

Topic: Bone Tumors
A 9-year-old girl reports progressive right knee pain. Radiographs are shown in Figures 59a and 59b. Work-up reveals no other sites of disease. Low- and high-power photomicrographs are shown in Figures 59c and 59d. What is the most appropriate treatment?
. Chemotherapy alone
. Surgery alone
. Radiation therapy alone
. Chemotherapy and surgery
. Radiation therapy and surgery

Correct Answer & Explanation

. Chemotherapy and surgery

Explanation

This classic case of osteosarcoma illustrates the typical radiographic and histologic characteristics of this disease. The radiographs show an aggressive-appearing lesion of the distal femur. The lesion has both lytic and blastic areas. Periosteal reaction is present in the form of a Codman’s triangle. The radiographs are highly suggestive of osteosarcoma. The photomicrographs show malignant spindle cells that produce osteoid, thus confirming the diagnosis of osteosarcoma. Treatment of osteosarcoma is multimodal including multi-agent chemotherapy and surgery (wide resection or amputation).

Question 248

Topic: Bone Tumors

A 9-year-old girl has had bilateral knee and leg pain for the past 2 years. The family has noted increasing deformity in both lower extremities. She is less than the fifth percentile for height. Examination reveals bilateral femoral bowing, mild medial-lateral laxity of the knees, and the deformities shown in the radiograph seen in Figure 3. What is the most likely diagnosis? Review Topic

. Renal osteodystrophy
. Diastrophic dysplasia
. Metaphyseal dysplasia
. Osteogenesis imperfecta
. Fibrous dysplasia

Correct Answer & Explanation

. Renal osteodystrophy

Explanation

The widening, bowing, and cupping of the physes indicate some form of metabolic bone disease; therefore, the most likely diagnosis is renal osteodystrophy. The age of onset makes X-linked hypophosphatemic rickets less likely. The ground glass lesions and widening of the medullary canal characteristic of fibrous dysplasia are not present. There are no fractures creating the deformities indicating osteogenesis imperfecta. There is an asymmetry of the deformities that makes diastrophic dysplasia less likely.

Question 249

Topic: Bone Tumors

EXT1

. This patient has multiple hereditary exostoses. Widening of the metaphysis is characteristic of multiple hereditary exostoses. Large sessile osteochondromas arise from the metaphysis and a large osteochondroma arises from the medial metaphysis with a characteristic cartilaginous cap. The computed tomography scan shows the widening and abnormal tubulation of the bone.
. No evidence of malignancy exists in this large osteochondroma. The cartilage cap is regular with no areas of bone destruction. One should also look for a soft tissue mass, which often shows areas of focal calcifications. No soft tissue masses are present in this patient.
. It is important to remember that this condition is autosomal dominant. The putative tumor suppressive gene mutation is EXT1, EXT2. The risk of low-grade chondrosarcoma occurring in this condition is approximately 10%.

Correct Answer & Explanation

. This patient has multiple hereditary exostoses. Widening of the metaphysis is characteristic of multiple hereditary exostoses. Large sessile osteochondromas arise from the metaphysis and a large osteochondroma arises from the medial metaphysis with a characteristic cartilaginous cap. The computed tomography scan shows the widening and abnormal tubulation of the bone.

Explanation

slide 1 slide 2 slide 3A patient presents with a hard leg mass and pain with activity. The anteroposterior and lateral radiographs are shown in Slide 1 and Slide 2. An axial computed tomography scan is shown in Slide 3. Which of the following would be the most appropriate treatment:

Question 250

Topic: Bone Tumors
A 10-year-old child has leg discomfort with activity. A radiograph, bone scan, and biopsy specimen are shown in Figures 1a through 1c. What is the most likely diagnosis?
. Parosteal osteosarcoma
. Unicameral bone cyst
. Aneurysmal bone cyst
. Eosinophilic granuloma
. Fibrous dysplasia

Correct Answer & Explanation

. Fibrous dysplasia

Explanation

The ground-glass appearance on the radiograph, the hot bone scan, and histologic findings of bony spicules without osteoblastic rimming in a background of bland fibrous tissue all suggest fibrous dysplasia. Stress-related pain is common with activity because of the dysplastic bone. Parosteal osteosarcomas are surface lesions. Simple cysts, aneurysmal bone cysts, and eosinophilic granuloma are all possible radiographically; however, the histology is most consistent with fibrous dysplasia.

Question 251

Topic: Bone Tumors
Figure 12 shows a lateral radiograph of the elbow. What is the most likely diagnosis?
. Osteochondroma
. Old fracture fragment
. Heterotopic ossification
. Normal anatomic variant
. Osteosarcoma

Correct Answer & Explanation

. Normal anatomic variant

Explanation

The figure shows a supracondylar process, which is a normal anatomic variant. An osteochondroma tends to occur more toward the end of bones, and the medullary space of the underlying bone extends into the base of the osteochondroma. The presence of a supracondylar process is usually asymptomatic.

Question 252

Topic: Bone Tumors

Which of the following is a function of siRNA (small interfering RNA)?

. Identifies proteins
. Blocks transcription of DNA
. Separates DNA based on size
. Blocks translation of mRNA
. Identifies DNA sequences

Correct Answer & Explanation

. Identifies proteins

Explanation

siRNA functions by causing mRNA to be broken down after transcriptions, resulting in an inability to undergo translation.siRNA are short (usually 20 to 24-bp) double-stranded RNA (dsRNA) sequences with phosphorylated 5' ends and hydroxylated 3' ends. Because of their ability to block a gene of interest, they have been generating interest in the treatment of disease processes that involve gene expression.Noh et al. study the affects of PD98059, an extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor, on osteosarcoma. They found that blocking the ERK1/2 pathway with PD98059 induces osteosarcoma cell death by inhibiting a potential drug-resistance mechanism.Illustration A shows how siRNA works to block translation of mRNA. Incorrect Answers:

Question 253

Topic: Bone Tumors

-A 14-year-old girl has a painless deformity of the right tibia. A radiograph from 2 years ago is seen in Figure a; nothing was done at that time. Her current radiograph is seen in Figure b. She has no pain, fever, or drainage. What is the most likely diagnosis?

. Adamantinoma
. Fibrous dysplasia
. Osteofibrous dysplasia
. Nonossifying fibroma
. Chronic osteomyelitis

Correct Answer & Explanation

. Adamantinoma

Explanation

Question 254

Topic: Bone Tumors
A 23-year-old man has had right posterolateral knee pain and occasional lateral calf dysesthesias for the past 8 months. A radiograph, CT scan, MRI scans, and a biopsy specimen are shown in Figures 62a through 62e. What is the most likely diagnosis?
. Osteoid osteoma
. Brodie’s abscess
. Osteoblastoma
. Chondroblastoma
. Osteosarcoma

Correct Answer & Explanation

. Osteoid osteoma

Explanation

The radiograph shows an eccentric, cortically based lytic lesion in the proximal fibula. The CT and MRI scans confirm that it is well-circumscribed and cortically based with significant surrounding edema. The radiographic differential diagnosis would be a Brodie’s abscess or osteoid osteoma. An osteoblastoma would have to be greater than 2 cm in size. A chondroblastoma may also have significant edema around it, but it is an epiphyseal-based lesion, not cortically based. The pathology shows a very cellular and vascular stroma with plump, but not atypical osteoblast cells making a matrix of immature woven bone. Therefore, the clinical and histologic picture is most consistent with an osteoid osteoma.

Question 255

Topic: Bone Tumors
A 22-year-old man has mild hip pain bilaterally and multiple skeletal lesions. Based on the pelvic radiograph shown in Figure 30, what is the inheritance pattern for his disorder?
. X-linked
. Autosomal recessive
. Autosomal dominant
. Mitochondrial inheritance
. Germline mutation

Correct Answer & Explanation

. Autosomal dominant

Explanation

DISCUSSION: Multiple hereditary exostoses (MHE) is an autosomal dominant disorder manifested by multiple osteochondromas and characteristic skeletal involvement. EXT1 on 8q24.1 and EXT2 on 11p13 are the two genes most strongly associated with MHE. Mutations in these genes affect proper development of endochondral bone, such that in all affected individuals exostoses develop adjacent to the growth plates of long bones, and some exhibit additional bone deformities. Defects in the EXT genes result in increased chondrocyte proliferation and delayed hypertrophic differentiation.

Question 256

Topic: Bone Tumors
What percent of patients initially diagnosed with classic, high-grade osteosarcoma of the extremity have visible evidence of pulmonary metastasis on CT of the chest?
. 5% to 10%
. 10% to 20%
. 40% to 50%
. 60% to 80%
. 80% to 90%

Correct Answer & Explanation

. 10% to 20%

Explanation

CT studies show that approximately 10% to 20% of patients with high-grade osteosarcoma have pulmonary metastases at diagnosis. Although not visible on current staging studies, it is believed that up to 80% of patients have micrometastatic disease that requires systemic chemotherapy.

Question 257

Topic: Bone Tumors
A 65-year-old man has a painful right hip mass that has been growing for several years. A radiograph, CT scan, and photomicrograph are shown in Figures 56a through 56c. What is the most appropriate treatment?
. Chemotherapy alone
. Surgery alone
. Radiation therapy alone
. Chemotherapy and surgery
. Radiation therapy and surgery

Correct Answer & Explanation

. Surgery alone

Explanation

DISCUSSION: This is a conventional chondrosarcoma. The radiograph and the CT scan show a lesion arising from the inferior pubic ramus with a large soft-tissue mass. Abundant punctate, stippled, or “popcorn-like” calcification is present. The photomicrograph demonstrates hypercellular cartilage. Surgical resection is the only effective treatment. Whereas chemotherapy might play a role in the treatment of a dedifferentiated chondrosarcoma, it has no role in the treatment of a conventional chondrosarcoma. Chondrosarcomas are relatively radioresistant.

Question 258

Topic: Bone Tumors
A 13-year-old premenarchal girl presents with back pain and scoliosis. Figures A through D are the bone scan, SPECT scan, axial and coronal images respectively. What is the most likely diagnosis?
. Metastasis
. Aneurysmal bone cyst
. Osteoblastoma
. Osteoid osteoma
. Eosinophilic granuloma

Correct Answer & Explanation

. Osteoid osteoma

Explanation

This patient has osteoid osteoma (OO). OO and osteoblastoma (OB) of the spine commonly present in the 2nd decade of life. CT shows a low attenuation nidus with central mineralization and varying degrees of perinidal sclerosis. NSAIDs are thought to inhibit PGE2 and PGI2 produced within the nidus, and suppress perinidal edema arising from high levels of COX2 expression in neoplastic nidal osteoblasts. OOs of the spine are the most common cause of painful scoliosis in children and young adults. Figures A and B are bone scan and SPECT scans respectively that demonstrate intense tracer uptake in the left transverse process of L3 characteristic of an osteoid osteoma. Figures C and D are axial and coronal reconstructed CT images showing a lesion of the left transverse process of L3 with a dense "nidus" with surrounding lucency characteristic of osteoid osteoma.

Question 259

Topic: Bone Tumors
Figure 15a shows the radiograph of a patient who has a chondrosarcoma of the acetabulum. Bone scans are shown in Figures 15b and 15c. Numerous soft subcutaneous masses are present. A clinical photograph of the hand is shown in Figure 15d. What is the most likely diagnosis?
. Multiple hereditary exostosis
. Ollier’s disease
. Maffucci’s syndrome
. McCune-Albright syndrome
. Neurofibromatosis

Correct Answer & Explanation

. Maffucci’s syndrome

Explanation

DISCUSSION: Chondrosarcomas associated with diffuse bone lesions (enchondromas) are characteristic of Ollier’s disease. When accompanied by subcutaneous masses (hemangiomas), the condition is called Maffucci’s syndrome. Multiple hereditary exostosis is characterized by diffuse osteochondromas. McCune-Albright syndrome is characterized by polyostotic fibrous dysplasia with café-au-lait spots and precocious puberty. Neurofibromatosis can have associated bone lesions but is not associated with chondrosarcomas.

Question 260

Topic: Bone Tumors
A 40-year-old woman has a symptomatic mass on the anterior aspect of the ankle. She reports no constitutional symptoms. An MRI scan is shown in Figure 12. What is the most likely diagnosis?
. Ganglion
. Osteosarcoma
. Aneurysmal bone cyst
. Unicameral bone cyst
. Gouty tophi

Correct Answer & Explanation

. Ganglion

Explanation

The MRI scan reveals a lobular mass that is below the vitamin E tablet marker taped to the skin. This is juxtaposed to the tibialis anterior tendon. It is slightly more enhanced than the surrounding subcutaneous fat and is consistent with a ganglion. Osteosarcoma, aneurysmal bone cyst, or unicameral bone cyst all would demonstrate enhancement or pathology in the bone. This is clearly a well-defined soft-tissue mass. Gouty tophi show low to intermediate signal on T1- and T2-weighted images.

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