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Bone Tumors MCQs

Practice Set 14 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 261

Topic: Bone Tumors
A 9-year-old boy has a painless enlarged mass on the dorsum of his hand. Figures 14a through 14d show the clinical photograph, radiographs, and biopsy specimen. What is the most likely diagnosis?
. Fracture callus
. Enchondroma (Ollier’s disease)
. Multiple hereditary exostosis
. Osteosarcoma
. Chondrosarcoma

Correct Answer & Explanation

. Multiple hereditary exostosis

Explanation

DISCUSSION: Multiple hereditary exostosis and enchondroma commonly present as multiple lesions in the hand. Multiple hereditary exostosis consists of cartilage capped bony exostoses arising from the metaphyseal end of rapidly growing bones. Osteosarcoma and chondrosarcoma rarely appear as multiple lesions. Fracture callus can exhibit enchondral ossification that is usually circumferential, but the radiographic findings are not consistent with fracture. REFERENCES: Porter DE, Emerton ME, Villanueva-Lopez F, Simpson AH: Clinical and radiographic analysis of osteochondromas and growth disturbance in hereditary multiple exostoses. J Pediatr Orthop 2000;20:246-250. Pierz KA, Stieber JR, Kusumi K, Dormans JP: Hereditary multiple exostoses: One center’s experience and review of etiology. Clin Orthop 2002;402:49-59.

Question 262

Topic: Bone Tumors
A 79-year-old healthy male has 1 year of progressively worse left hip pain. He denies any significant weight loss but does complain of night pain. Radiograph and MRI are shown in Figures A & B. Bone scan and histology is shown in Figures C-E. What is the definitive treatment of this?
. observation
. radiation therapy alone
. wide resection and reconstruction
. wide resection, reconstruction and chemotherapy
. wide resection, reconstruction and local radiation therapy.

Correct Answer & Explanation

. wide resection and reconstruction

Explanation

The history, imaging and pathology points to chondrosarcoma as the diagnosis, and therefore wide resection and reconstruction is the most appropriate treatment. Chondrosarcoma tends to occur in an older individuals and the most common sites of origin are the femur, tibia, humerus, ribs, scapula then pelvis. Chondrosarcomas grow slowly and patients present with dull aching pain. X-rays typically have a subtle, radiolucent, permeative lesion or may have hazy or speckled calcifications with either a diffuse "salt & pepper" pattern or a more discrete "popcorn" pattern. The MRI defines the amount of marrow and soft-tissue involvement, and typically has high T2 signal intensity. Bone scintigraphy will be positive. In pathological sections, low-power imaging demonstrates lobulated clusters of chondrocytes, and high-power imaging demonstrates a bland cellular appearance, extensive basophilic cytoplasm, and no mitotic figures (low grade chondrosarcoma).

Question 263

Topic: Bone Tumors
A previously asymptomatic 12-year-old girl sustained a direct blow to the right lateral knee from a baseball bat. Examination reveals an area of ecchymosis and tenderness over the lateral thigh. The patient can walk without pain, but range of motion of the knee causes discomfort. Plain radiographs of the knee are shown in Figures 11a and 11b. To address the bone lesion, management should consist of
. a three-phase bone scan.
. CT.
. MRI.
. a repeat examination in 6 weeks.
. a biopsy.

Correct Answer & Explanation

. a repeat examination in 6 weeks.

Explanation

The plain radiographs reveal a pedunculated osteochondroma with a fracture. There is a bony growth in the metaphysis of a long bone, on a stalk that is directed away from the nearby epiphysis. On the AP view, the host cortical and medullary bone are shown as “blending” with lesional bone. There is also a fracture through the lesion. Based on these radiographic findings, the diagnosis is an osteochondroma; therefore, initial management of an acute fracture of an osteochondroma is symptomatic treatment alone. Additional imaging studies are not indicated in this patient.

Question 264

Topic: Bone Tumors
Initial management of a pathologic fracture of the humerus secondary to a unicameral bone cyst should include
. open curettage and bone grafting.
. intralesional steroid injection.
. percutaneous grafting with a bone graft substitute.
. immobilization until the fracture heals.
. MRI.

Correct Answer & Explanation

. immobilization until the fracture heals.

Explanation

DISCUSSION: Most pathologic humeral fractures secondary to a unicameral bone cyst are minimally displaced and should be immobilized and allowed to heal. Persistent and/or progressive lesions may require treatment. Various treatments of unicameral bone cysts have been described. Acceptable treatment options include curettage and bone grafting, intralesional steroid injection, and percutaneous grafting with bone graft substitutes. MRI is not indicated when the diagnosis of unicameral bone cyst is known. REFERENCES: Wilkins RM: Unicameral bone cysts. J Am Acad Orthop Surg 2000;8:217-224. Bensahel H, Jehanno P, Desgrippes Y, Pennecot GF: Solitary bone cyst: Controversies and treatment. J Pediatr Orthop B 1998;7:257-261.

Question 265

Topic: Bone Tumors

A 16-year-old boy presents with severe, progressive right-sided back pain that is worse at night and dramatically relieved by ibuprofen. Examination reveals a left-sided thoracic scoliosis. CT scan shows a 1 cm sclerotic lesion with a central lucent nidus in the right T8 pedicle. Which of the following best describes the relationship between the lesion and the scoliotic curve?

. The lesion is located on the convexity of the curve.
. The lesion is located on the concavity of the curve.
. The curve is structural and will not resolve after lesion excision.
. The lesion is located at the apex of a compensatory lumbar curve.
. The curve magnitude correlates inversely with the patient's age.

Correct Answer & Explanation

. The lesion is located on the convexity of the curve.

Explanation

In spinal osteoid osteoma, muscle spasms on the side of the lesion cause a secondary scoliosis. The lesion is characteristically located on the concave side of the scoliotic curve.

Question 266

Topic: Bone Tumors
What process is often found associated with other neoplasms?
. Osteomyelitis
. Osteoblastoma
. Aneurysmal bone cyst
. Giant cell tumor
. Eosinophilic granuloma

Correct Answer & Explanation

. Aneurysmal bone cyst

Explanation

Aneurysmal bone cyst may be either a “pattern” or a “diagnosis.” Therefore, aneurysmal bone cyst should be viewed as a diagnosis of exclusion. Hemorrhage into a variety of primary bone lesions (e.g., giant cell tumor of bone, chondroblastoma, osteoblastoma, fibrous dysplasia, osteosarcoma, or vascular neoplasms) may result in intralesional, membrane-bone blood-filled cysts. Such secondary changes may be confused with aneurysmal bone cyst, resulting in inappropriate therapy because assessment should be focused on identifying the underlying primary process. The entire specimen should be examined histologically in an effort to locate an underlying primary bone tumor.

Question 267

Topic: Bone Tumors

Figure 6a through 6c

. Curettage and/or grafting
. Radiofrequency ablation
. Intravenous (IV) antibiotics
. Incision, drainage, and IV antibiotics
. Neoadjuvant chemotherapy followed by surgical reconstruction
. Observation alone

Correct Answer & Explanation

. Curettage and/or grafting

Explanation

DISCUSSIONFigure 2 depicts a typical unicameral bone cyst with a pathologic fracture. The decision to treat this lesion should be based on the amount of cortical thinning. If these lesions involve a pathologic fracture, many surgeons will treat them nonsurgically to see if the fracture stimulates healing of the cyst. If the cyst wall remains thin or the patient is symptomatic, then treatment is directed at decreasing cyst volume, increasing cortical thickness, and eliminating symptoms. This can be accomplished by curettage and grafting, injection with autogenous bone marrow, or grafting with 1 of the many available bone void fillers. In some cases, internal fixation may be required. This typically is accomplished with flexible intramedullary nails.Figure 3 shows a typical nonossifying fibroma. These benign lesions are usually incidental findings on a radiograph and often resolve in adulthood. Treatment usually is not required, and these lesions typically do not produce symptoms.Figure 4 shows an osteoid osteoma of the femoral neck. This is characterized by a central radiolucent nidus surrounded by reactive bone with increased radiodensity. These lesions are painful because of the large amount of prostaglandin they secrete. They temporarily respond to oral anti-inflammatory drugs. Treatment is directed at eliminating the nidus and can be done through curettage, but radiofrequency ablation, which allows for a minimally invasive approach, is often used today.Figure 5 shows diskitis with vertebral osteomyelitis. The disease is characterized by fever and back pain. Movement is extremely uncomfortable for these children, and they may adopt unusual postures to alleviate pain. The MRI shows involvement of 1 vertebrae and an adjacent disk. Left untreated, this condition often spreads to involve multiple vertebrae and also can cause an epidural abscess. Treatment during the early stages is IV antibiotics. Many orthopaedic surgeons also use bracing to prevent late vertebral collapse.Figures 6a through 6c show septic arthritis of the ankle with metaphyseal osteomyelitis. The recommended treatment is incision and drainage followed by IV antibiotics. MRI may be considered before surgery to assess for an associated osteomyelitis or abscess that may also necessitate surgical debridement. Increasingly, these scenarios are managed with a rapid transition to oral antibiotics.

Question 268

Topic: Bone Tumors
A 23-year-old woman reports right knee pain and fullness. The pain is worse with activity but also present at rest. Radiographs are shown in Figures 20a and 20b. What is the most likely diagnosis?
. Osteosarcoma
. Chondroblastoma
. Stress fracture
. Posttraumatic changes
. Chondrosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The radiographs reveal a predominantly lytic, destructive lesion of the distal femur, although there is a hint of some blastic change as well. The lesion has violated the cortex, and there is mineralization outside the cortex laterally. The lateral radiograph suggests a soft-tissue density. These aggressive changes on radiographs in this age group are strongly suggestive of osteosarcoma.

Question 269

Topic: Bone Tumors

A 16-year-old boy has night pain in his tibia relieved by NSAIDs. CT shows a 6 mm radiolucent nidus surrounded by sclerotic bone. Radiofrequency ablation (RFA) is planned. RFA is contraindicated if the lesion is located within what distance of a major motor nerve?

. 1 mm
. 5 mm
. 10 mm
. 15 mm
. 20 mm

Correct Answer & Explanation

. 10 mm

Explanation

Radiofrequency ablation is the treatment of choice for most osteoid osteomas. However, it is generally contraindicated if the nidus is located within 1 cm (10 mm) of a major nerve or the spinal cord to avoid thermal neural injury.

Question 270

Topic: Bone Tumors

A 15-year-old male presents with night pain in his tibia that is relieved by NSAIDs. Radiographs show a small radiolucent nidus surrounded by dense sclerotic bone. Which inflammatory mediator is found in high concentrations within the nidus?

. Interleukin-1
. Tumor necrosis factor-alpha
. Prostaglandin E2
. Leukotriene B4
. Histamine

Correct Answer & Explanation

. Prostaglandin E2

Explanation

Osteoid osteomas secrete high levels of prostaglandins, specifically Prostaglandin E2, which causes the characteristic intense night pain. This is the mechanism by which NSAIDs provide dramatic pain relief.

Question 271

Topic: Bone Tumors

A 65-year-old male presents with generalized bone pain and fatigue. Radiographs show multiple punched-out lytic lesions in the skull and long bones. A technetium-99m bone scan is negative in the areas of the lytic lesions. What is the most common laboratory abnormality associated with this condition?

. Elevated carcinoembryonic antigen
. Monoclonal immunoglobulin spike on serum protein electrophoresis
. Elevated serum alkaline phosphatase
. Decreased serum albumin
. Elevated alpha-fetoprotein

Correct Answer & Explanation

. Monoclonal immunoglobulin spike on serum protein electrophoresis

Explanation

Multiple myeloma typically presents with punched-out lytic lesions that appear cold on a technetium bone scan due to lack of osteoblastic activity. Diagnosis is supported by an M-spike (monoclonal immunoglobulin) on serum or urine protein electrophoresis.

Question 272

Topic: Bone Tumors

A 20-year-old man presents with a 'shepherd's crook' deformity of his proximal femur. Radiographs display a ground-glass appearance. This skeletal pathology is associated with a somatic activating mutation in the GNAS1 gene. If accompanied by cafe-au-lait spots, what endocrine disorder is most classically associated?

. Primary hyperparathyroidism
. Precocious puberty
. Hypothyroidism
. Cushing's disease
. Diabetes insipidus

Correct Answer & Explanation

. Precocious puberty

Explanation

The patient has fibrous dysplasia. When polyostotic fibrous dysplasia occurs with cafe-au-lait spots and endocrine hyperfunction, it is known as McCune-Albright syndrome. The most common endocrine abnormality in this syndrome is precocious puberty.

Question 273

Topic: Bone Tumors

A 19-year-old male presents with dull, aching pain in his right tibia that is worse at night and dramatically relieved by NSAIDs. CT scan shows a 7 mm radiolucent nidus surrounded by dense reactive sclerosis in the anterior tibial cortex. What is the most appropriate definitive, minimally invasive treatment?

. Intralesional curettage with structural bone grafting
. Wide en bloc surgical resection
. Radiofrequency ablation (RFA)
. Stereotactic body radiation therapy (SBRT)
. Percutaneous ethanol injection

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The clinical presentation (night pain relieved by NSAIDs) and CT findings (radiolucent nidus < 1.5 cm with surrounding sclerosis) are classic for osteoid osteoma. CT-guided radiofrequency ablation (RFA) is the standard of care, offering definitive treatment with minimal morbidity compared to open surgery.

Question 274

Topic: Bone Tumors

A 17-year-old male presents with night pain in the proximal femur that is dramatically relieved by NSAIDs. CT scan shows a 7 mm radiolucent nidus surrounded by dense sclerotic bone in the femoral neck, located 3 mm from the articular cartilage. What is the most appropriate definitive management?

. Percutaneous radiofrequency ablation
. Observation alone
. Intralesional curettage or en bloc excision
. Intravenous bisphosphonates
. Radiation therapy

Correct Answer & Explanation

. Intralesional curettage or en bloc excision

Explanation

The diagnosis is osteoid osteoma. While radiofrequency ablation (RFA) is the standard of care for most osteoid osteomas, lesions located within 1-1.5 cm of critical structures such as articular cartilage or major nerves are generally considered contraindicated for RFA due to the high risk of thermal necrosis to the cartilage. In this case, surgical curettage or excision is the preferred treatment.

Question 275

Topic: Bone Tumors
Compared with amputation, limb salvage for osteosarcoma of the distal end of the femur will result in:
. an improved chance for long-term survival.
. an improved quality of life.
. a lessened need for chemotherapy.
. a better functional outcome.
. a reduced need for reoperation.

Correct Answer & Explanation

. a better functional outcome.

Explanation

Major advances in diagnostic imaging, neoadjuvant chemotherapy, and surgical techniques have allowed limb salvage to be performed as an alternative to amputation in children with osteosarcoma. The outcome of treatment of nonmetastatic, high-grade osteosarcoma of the distal femur was studied in 227 patients from 26 institutions. The authors found no difference in the long-term survival or quality of life between patients treated with limb salvage and those treated with amputation. Patients treated with limb salvage had a higher rate of reoperation, but a better functional outcome.

Question 276

Topic: Bone Tumors
Figures 4a through 4c show the radiographs, CT scans, and T1-weighted MRI scan of a 19-year-old man who has had increasing right hip pain and decreasing range of motion for the past several years. He also reports intermittent “locking” of the hip. What is the most likely diagnosis?
. Chondrosarcoma
. Stress fracture
. Osteochondroma
. Osteosarcoma
. Synovial osteochondromatosis

Correct Answer & Explanation

. Synovial osteochondromatosis

Explanation

DISCUSSION: The radiographs reveal small ossified masses around the femoral neck. The CT scans also show these masses and suggest that they are separate from the underlying cortex of the femoral neck, although they abut it. The MRI scan does not reveal significant marrow changes in the proximal femur apart from some mild reactive changes immediately adjacent to the nodules. These findings suggest a synovial or joint-based disorder as opposed to a primary bone tumor. The most likely diagnosis is synovial osteochondromatosis, which is consistent with the patient’s mechanical symptoms. REFERENCES: Crotty JM, Monu JU, Pope TL Jr: Synovial osteochondromatosis. Radiol Clin North Am 1996;34:327-342. Frassica F: Orthopaedic pathology, in Miller M (ed): Review of Orthopaedics, ed 2. Philadelphia, PA, WB Saunders, 1996, pp 292-335.

Question 277

Topic: Bone Tumors

A 23-year-old man has had heel pain and fullness for the past several months. He reports that initially the pain was present only with activity, but more recently the pain has become constant. Figures 53a through 53d show a radiograph, a bone scan, and T2-weighted and gadolinium MRI scans. What is the most likely diagnosis?

. Chondroblastoma
. Fibrous dysplasia
. Simple bone cyst
. Aneurysmal bone cyst
. Giant cell tumor

Correct Answer & Explanation

. Aneurysmal bone cyst

Explanation

The imaging studies reveal an expansile lesion with the classic soap bubble appearance that involves most of the calcaneus. The bone scan reveals a very active lesion with intense uptake, and the MRI scans show the classic, loculated appearance of the lesion with multiple fluid-fluid levels. While it is important to rule out telangiectatic osteosarcoma, the most likely diagnosis is an aneurysmal bone cyst. While giant cell tumor might have a similar appearance, the multiple fluid levels in a expansile lesion strongly favor an aneurysmal bone cyst. Parsons TW: Benign bone tumors, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1027-1035.

Question 278

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). Bacci G, Ferrari S, Bertoni F, et al: Long-term outcome for patients with nonmetastatic osteosarcoma of the extremity treated at the Instituto Ortopedico Rizzoli according to the Instituto Ortopedico Rizzoli/osteosarcoma-2 protocol: An updated report. J Clin Oncol 2000;18:4016-4037. Bielack SS, Kempf-Bielack B, Delling G, et al: Prognostic factors in high-grade osteosarcoma of the extremities or trunk: An analysis of 1,702 patients treated on neoadjuvant cooperative osteosarcoma study group protocols. J Clin Oncol 2002;20:776-790.

Question 279

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

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. Donati D, El Ghoneimy A, Bertoni F, et al: Surgical treatment and outcome of conventional pelvic chondrosarcoma. J Bone Joint Surg Br 2005;87:1527-1530. Lee FY, Mankin HJ, Fondren G, et al: Chondrosarcoma of bone: An assessment of outcome. J Bone Joint Surg Am 1999;81:326-338.

Question 280

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?

Basic Science Board Review 2008: High-Yield MCQs (Set 2) - Figure 28

. X-linked
. Autosomal recessive
. Autosomal dominant
. Mitochondral inheritance
. Germline mutation

Correct Answer & Explanation

. Autosomal dominant

Explanation

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. Stieber JR, Dormans JP: Manifestations of hereditary multiple exostoses. J Am Acad Orthop Surg 2005;13:110-120.

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