Musculoskeletal Neoplasms



Musculoskeletal Neoplasms


Hillary W. Garner

Jeffrey J. Peterson

Thomas H. Berquist

Mark J. Kransdorf



▪ BONE TUMORS/TUMORLIKE CONDITIONS: IMAGING APPROACHES


KEY FACTS



  • Imaging studies are essential for detecting, characterizing, and staging bone lesions.


  • Radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and radionuclide scans all play a role. Angiography is useful for evaluating tumor vascularity and for preoperative embolization.


  • Effectiveness of imaging studies for evaluating features of bone tumors is as follows:


































    Radiographs


    CT


    MRI


    Nuclear Medicine


    Lesion morphology


    Thin cortical bone


    Lesion extent


    Early detection in marrow and soft tissues


    Site (cortical, marrow, diaphysis, metaphysis, epiphysis)


    Bone destruction or production


    Joint space involvement


    Skip lesions


    Bone production or destruction


    Periosteal response


    Marrow edema patterns


    Metastasis


    Periosteal response


    Calcifications/matrix


    Cortical destruction


    Soft tissue calcification or ossifications


    Trabecular destruction




    CT, computed tomography; MRI, magnetic resonance imaging.




SUGGESTED READING

Fitzgerald JJ, Roberts CC, Daffner RH, et al. Follow-Up of Malignant or Aggressive Musculoskeletal Tumors. Reston: American College of Radiology; 2011.

Garner HW, Kransdorf MJ. Musculoskeletal sarcoma: update on imaging of the post-treatment patient. Can Assoc Radiol J. 2016;67(1):12-20.

Hwang S, Panicek DM. The evolution of musculoskeletal tumor imaging. Radiol Clin North Am. 2009;47(3):435-453.

Kransdorf MJ, Bridges MD. Current developments and recent advances in musculoskeletal tumor imaging. Semin Musculoskelet Radiol. 2013;17(2):145-155.

Mintz DN, Hwang S. Bone tumor imaging, then and now. HSS J. 2014;10(3):230-239.

Morrison WB, Weissman BN, Kransdorf MJ, et al. ACR appropriateness criteria—primary bone tumors. Reston: American College of Radiology; 2013.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: RADIOGRAPHIC FEATURES


KEY FACTS



  • Patient’s age and lesion location are the two most helpful pieces of information when evaluating a bone lesion. Routine radiographs provide additional important information to further narrow the diagnostic possibilities. Key discriminatory radiographic features are as follows:



    • Patterns of bone destruction:



      • Geographic: least aggressive. Margins may be sclerotic, well defined without sclerosis, or ill defined.


      • Moth-eaten: more aggressive, less well defined. Wider zone of transition. Seen with malignant lesions and osteomyelitis.


      • Permeative: most aggressive with more rapid destruction. Margins not defined. Seen with aggressive malignancies and infections.


    • Bone formation



      • Matrix—calcification or ossification


      • Trabeculation—seen with giant cell tumors, chondromyxoid fibroma, aneurysmal bone cyst, hemangioma, nonossifying fibroma


      • Cortical breach/penetration


      • Periosteal response


      • Soft tissue mass


    • Distribution:



      • Central, eccentric, cortical, and juxtacortical


      • Diaphyseal, metaphyseal, and epiphyseal


      • Skeletal location (e.g., tibia and calcaneus)






FIGURE 9-1. Patterns of bone destruction—geographic. Anteroposterior (AP) radiograph of the left shoulder (A) shows a well-defined geographic lucent lesion with sclerotic septations and a sclerotic margin (arrows) in the proximal humeral metaphysis. Corresponding sagittal fat-saturated T2-weighted magnetic resonance (MR) image (B) more clearly shows the geographic nature of this nonossifying fibroma.







FIGURE 9-2. Patterns of bone destruction—moth-eaten. Anteroposterior (AP) radiograph of the right humerus shows a moth-eaten appearance of the proximal humerus with poorly defined margins as the result of breast cancer metastasis.






FIGURE 9-3. Patterns of bone destruction—permeative. Anteroposterior (AP) radiograph of the left forearm shows poorly defined lytic lesions in the radius and ulna with permeative cortical changes corresponding to breast cancer metastases. There is a pathologic minimally displaced transverse fracture of the radial shaft (arrow).







FIGURE 9-4. Matrix calcifications. Axial computed tomography (CT) image of the distal tibial epiphysis shows a well-defined geographic lesion with calcifications. Appearance and location are characteristic of chondroblastoma.






FIGURE 9-5. Aggressive periosteal response. Lateral view of the left knee (A) shows an osteogenic sarcoma with osteoid matrix, soft tissue extension, triangular elevation (Codman triangles) (arrow), and sunburst periosteal reaction (arrowhead). Anteroposterior (AP) view of the left femur (B) shows an osteogenic sarcoma with onion-skin periosteal reaction. Codman triangles, sunburst periosteal reaction, and onion-skin periosteal reaction are associated with aggressive lesions.




SUGGESTED READING

Caracciolo JT, Temple HT, Letson GD, et al. A modified Lodwick-Madewell grading system for the evaluation of lytic bone lesions. Am J Roentgenol. 2016;207(1):150-156.

Miller TT. Bone tumors and tumorlike conditions: analysis with conventional radiography. Radiology. 2008;246(3):662-674.

Morrison WB, Weissman BN, Kransdorf MJ, et al. ACR Appropriateness Criteria—Primary Bone Tumors. Reston: American College of Radiology; 2013.

Sundaram M, McLeod RA. MR imaging of tumors and tumorlike lesions of bone and soft tissue. Am J Roentgenol. 1990;155(4):817-824.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: MAGNETIC RESONANCE IMAGING PROTOCOLS


KEY FACTS



  • MRI of bone tumors often requires individualized customization of the imaging protocol compared with other indications for MRI.


  • The coil and the field of view should be selected to best center the lesion of concern for optimal characterization. However, at least one sequence of the MRI examination should be obtained with a large field of view of the entire bone in question to evaluate for skip lesions and possible joint involvement.


  • Image planes should be selected to demonstrate the entire bone of interest on one image, particularly for long bones. This often requires doing oblique rather than “straight” coronal and/or sagittal imaging.


  • Coil selection should account for the anatomic area of interest.


  • Contrast enhancement is used routinely.






FIGURE 9-6. Optimal imaging protocol. Patients with a diaphyseal femoral sarcoma (arrow) and distal metaphyseal femoral skip lesions (arrowheads) confirmed after femoral resection. The skip lesions may be missed unless at least one sequence of the magnetic resonance (MR) examination is obtained with a large field of view of the entire bone in question.






FIGURE 9-7. Optimal imaging planes. Optimal coronal magnetic resonance (MR) image of distal femoral sarcoma with proximal skip lesion (arrowhead) shows the entire area of interest on one image with the level of excision marked for limb salvage (arrows). At least 3 cm of normal marrow is usually included in the resection.



SUGGESTED READING

Garner HW, Kransdorf MJ. Musculoskeletal sarcoma: update on imaging of the post-treatment patient. Can Assoc Radiol J. 2016;67(1):12-20.

Kransdorf MJ, Bridges MD. Current developments and recent advances in musculoskeletal tumor imaging. Semin Musculoskelet Radiol. 2013;17(2):145-155.

Morrison WB, Weissman BN, Kransdorf MJ, et al. ACR Appropriateness Criteria—Primary Bone Tumors. Reston: American College of Radiology; 2013.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: OSTEOID OSTEOMA


KEY FACTS



  • Clinical:



    • Osteoid osteoma is a relatively common lesion accounting for 10% of benign bone tumors. Patients present with pain, worse at night, often relieved by anti-inflammatory medications (75%).


  • Age: 5 to 35 years, peak second decade


  • Sex: Males outnumber females in the ratio 3:1.


  • Common locations: majority in lower extremity; proximal femur, femoral neck


  • Three types of osteoid osteoma:



    • Cortical: fusiform cortical thickening with a lucent nidus arising from the cortex


    • Cancellous: intramedullary in location. Often involve the femoral neck and small bones of the hand, foot, and posterior elements of the spine.


    • Subperiosteal: arise on the surface of bone. Often associated with surrounding solid continuous periosteal reaction.


  • Imaging features:



    • Radiographic features: small round lucent area with surrounding sclerosis and periosteal reaction. May have central calcification or ossification.


    • CT: technique of choice for detection and characterization


    • MRI: small focal lesion with surrounding reactive edema on fluid-sensitive sequences. Subtle lesions enhance with dynamic contrast studies.


  • Differential diagnosis:



    • Brodie abscess


    • Osteoblastoma


    • Stress fracture


  • Treatment: complete resection of nidus; percutaneous radiofrequency ablation






FIGURE 9-8. Osteoid osteoma. Oblique radiograph (A) and sagittal computed tomography (CT) (B) of the distal forearm demonstrate a lucent nidus with central mineralization in the radial volar aspect of the distal radial epiphysis. Sagittal T1-weighted magnetic resonance (MR) image (C) shows mild T1 hyperintensity relative to muscle of the nidus rim (arrowhead) with central T1 signal loss (arrow) corresponding to the mineralization seen on radiograph and CT. Axial T2-weighted image (D) shows edema-like signal in the marrow surrounding the lesion and the volar soft tissues adjacent to the lesion, but the lesion itself (arrow) is not well defined.







FIGURE 9-8. (continued)



SUGGESTED READING

Hakim DN, Pelly T, Kulendran M, Caris JA. Benign tumours of the bone: a review. J Bone Oncol. 2015;4(2):37-41.

Jordan RW, Koç T, Chapman AW, et al. Osteoid osteoma of the foot and ankle—a systematic review. Foot Ankle Surg. 2015;21(4):228-234.

Liu PT, Chivers FS, Roberts CC, et al. Imaging of osteoid osteoma by dynamic gadolinium-enhanced imaging. Radiology. 2003;277:691-700.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: OSTEOBLASTOMA


KEY FACTS



  • Clinical:



    • Osteoblastomas account for 3.5% of benign bone tumors. Patients present with chronic local pain.


  • Age: any age, most common second decade


  • Sex: Males outnumber females in the ratio 3:1.


  • Common locations: vertebrae (42.5%), posterior elements most commonly involved


  • Imaging features:



    • Radiographic features: may be similar to osteoid osteoma, but larger (>1.5 cm). May have malignant appearance. Bone expanded; 55% have an ossified matrix.


    • CT: cortical expansion, ossified matrix


    • MRI: variable, not well defined


  • Differential diagnosis:



    • Osteoid osteoma


    • Aneurysmal bone cyst


    • Osteosarcoma


  • Treatment: en bloc resection, bone grafting






FIGURE 9-9. Osteoblastoma. Lateral radiograph (A) and sagittal computed tomography (CT) image (B) of the lumbar spine demonstrate a rounded lucent lesion (arrow) in the left lamina of the L1 vertebral body. There is subtle internal mineralization and a thin cortical rim seen on the CT. Sagittal T1-weighted magnetic resonance (MR) image (C) shows a rounded lesion (arrow) with mild T1 hyperintensity relative to the paraspinal musculature (not shown). Sagittal postcontrast T1-weighted MR image (D) shows marked reactive enhancement in the soft tissues surrounding the lesion and only mild intralesional enhancement (arrow).







FIGURE 9-9. (continued)



SUGGESTED READING

Hakim DN, Pelly T, Kulendran M, Caris JA. Benign tumours of the bone: a review. J Bone Oncol. 2015;4(2):37-41.

McLeod RA, Dahlin DC, Beabout JW. The spectrum of osteoblastoma. Am J Roentgenol. 1976;126:321-335.

Unni KK. Dahlin’s Bone Tumors: General Aspects and Data on 11,087 Cases. Philadelphia: Lippincott-Raven; 1996:131-142.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: OSTEOCHONDROMA


KEY FACTS



  • Clinical:



    • Osteochondromas are the most common, accounting for 35% of benign skeletal neoplasms. Patients present with a palpable mass that may be painful.


  • Age: 5 to 50 years, peak second decade


  • Sex: Males outnumber females in the ratio 2:1.


  • Common locations: distal femur, proximal tibia, proximal humerus


  • Imaging features:



    • Radiographic features: bony projection with contiguous marrow and cortex from bone of origin


    • CT: similar to radiograph. Cartilaginous cap more easily appreciated (normal cap thickness <1.5 to 2 cm).


    • MRI: cartilage cap low intensity on T1-weighted and high intensity on T2-weighted sequences. Other features similar to radiographs.


  • Differential diagnosis:



    • Usually characteristic


  • Treatment: Observe unless symptoms or cosmetic deformity, then resect.






FIGURE 9-10. Osteochondroma. Anteroposterior (AP) radiograph (A) and axial T1-weighted (B) and axial fluid-sensitive (C) magnetic resonance (MR) images of the left lower leg show a distal tibial sessile lesion with corticomedullary continuity typical of osteochondroma. Note the chronic remodeling of the adjacent fibula on the radiograph (arrowheads). A thin hyperintense cartilage cap (arrow) is best seen on the fluid-sensitive MR image just deep to the chronically remodeled hypointense fibula (arrowheads).







FIGURE 9-10. (continued)






FIGURE 9-11. Osteochondroma. Axial computed tomography (CT) image of a proximal left tibial osteochondroma in a different patient again demonstrates the typical corticomedullary continuity (arrow).



SUGGESTED READING

Bernard SA, Murphey MD, Flemming DJ, et al. Improved differentiation of benign osteochondromas from secondary chondrosarcomas with standardized measurement of cartilage cap at CT and MR imaging. Radiology. 2010;255(3):857-865.

Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41(10):1195-1212.

Unni KK. Dahlin’s Bone Tumors: General Aspects and Data on 11,087 Cases. 5th ed. Philadelphia: Lippincott-Raven; 1996:11-24, 121-130, 355-432.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: ENCHONDROMA


KEY FACTS



  • Clinical:



    • Enchondromas account for 13.4% of benign bone tumors. Most are asymptomatic. If painful, low-grade chondrosarcoma should be excluded. Chondrosarcomas have more intense uptake on radionuclide scans and typically erode two-thirds of the cortical thickness. There may also be periosteal reaction and a soft tissue mass.


  • Age: all age groups, 55% in the second through fourth decades


  • Sex: no sex predilection


  • Common locations: small bones of hand and feet (50%) with 87% in the hand, proximal femur, and humerus


  • Imaging features:



    • Radiographic features: medullary with sharp margins. Calcification common. May be multiple.


    • CT: well-defined lesion with central calcified matrix. Cortical erosion easily measured.


    • MRI: lobulated low intensity on T1-weighted and high intensity on T2-weighted images. Useful for differentiating enchondroma from chondrosarcoma. Mineralized areas show decreased signal intensity on all pulse sequences.


  • Differential diagnosis:



    • Bone infarct


    • Chondrosarcoma


  • Treatment: observe. Curettage and bone graft if symptomatic.






FIGURE 9-12. Enchondroma. Anteroposterior (AP) radiograph (A) of the right hand demonstrates a lucent expansile lesion in the fourth metacarpal with endosteal scalloping (arrow), better delineated on the corresponding coronal computed tomography (CT) image (B). There is no associated intralesional matrix demonstrated on the radiograph or CT. The lesion is isointense to muscle on the coronal T1-weighted magnetic resonance (MR) image (C) and markedly hyperintense on fat-saturated T2-weighted MR image (D). The lesion demonstrates heterogeneous globular enhancement on the coronal postcontrast fat-saturated T1-weighted MR image (E). These radiographic, CT, and MR imaging features are typical of enchondroma in the small bones of the hands and feet.







FIGURE 9-12. (continued)







FIGURE 9-13. Enchondroma. Lateral radiograph (A) of the right knee demonstrates a geographic lesion in the distal femur with chondroid matrix and no endosteal scalloping. Sagittal T1-weighted (B), fat-saturated T2-weighted (C), and postcontrast fat-saturated T1-weighted (D) magnetic resonance (MR) images show the characteristic arc-and-ring morphology of enchondroma, with the peripheral areas of nonmineralized cartilage demonstrating typical iso- to slight hyperintensity on T1, hyperintensity on T2, and rim-like enhancement of the individual cartilage floccules. The central areas of mineralized cartilage demonstrate expected hypointensity on both T1 and T2 without enhancement. There is no marrow edema, cortical destruction, or soft tissue mass.



SUGGESTED READING

Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41(10):1195-1212.

Murphy MD, Flemming DJ, Boyea SR, et al. Enchondroma vs. chondrosarcoma in the appendicular skeleton: differentiating features. Radiographics. 1998;18:1213-1237.

Stomp W, Reijnierse M, Kloppenburg M, et al. Prevalence of cartilaginous tumours as an incidental finding on MRI of the knee. Eur Radiol. 2015;25(12):3480-3487.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: CHONDROBLASTOMA


KEY FACTS



  • Clinical:



    • Patients present with chronic local pain.


  • Age: 90% occur from 5 to 25 years of age, approximately 70% in second decade


  • Sex: Males outnumber females in the ratio 2 to 3:1.


  • Common locations: epiphyseal with 40% in the knee and 16% in the proximal humerus


  • Imaging features:



    • Radiographic features: epiphyseal location. Sharp margins with sclerotic rim. Calcification in approximately 50% to 60%.


    • CT: well-defined lesion with sclerotic margins and, frequently, central calcification


    • MRI: well-defined low-intensity lesion on T1-weighted and variably high signal intensity on T2-weighted sequences, with extensive surrounding edema in the majority of cases


  • Differential diagnosis:



    • Giant cell tumor


    • Avascular necrosis


    • Clear cell chondrosarcoma


  • Treatment: curettage and bone grafting






FIGURE 9-14. Chondroblastoma. Anteroposterior (AP) radiograph (A) demonstrates a subtle lucent lesion (arrow) in the lateral aspect of the right proximal tibial epiphysis with a sclerotic margin and faint intralesional calcifications. Coronal proton density fat-saturated magnetic resonance (MR) image (B) demonstrates a well-defined hyperintense lesion (arrow) with prominent edema-like signal in the surrounding marrow and adjacent soft tissues. Intraoperative radiograph (C) obtained during the later stage of curettage demonstrates a curette within the lesion cavity.




SUGGESTED READING

Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41(10):1195-1212.

Suneja R, Grimer RJ, Belthur M, et al. Chondroblastoma of bone: long-term results and functional outcome after intralesional curettage. J Bone Joint Surg Br. 2005;87:974-978.

Unni KK. Dahlin’s Bone Tumors: General Aspects and Data on 11,087 Cases. Philadelphia: Lippincott-Raven; 1996:47-57.

Weatherall PT, Moole GE, Mendelsohn DB, et al. Chondroblastoma: classic and confusing appearance at MR. Radiology. 1994;190:467-474.

Xu H, Nugent D, Monforte HL, et al. Chondroblastoma of bone in the extremities: a multicenter retrospective study. J Bone Joint Surg Am. 2015;97(11):925-931.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: CHONDROMYXOID FIBROMA


KEY FACTS



  • Clinical:



    • Patients present with local pain and swelling.


  • Age: 5 to 50 years, most common (55%) in the second and third decades


  • Sex: slightly more common in males


  • Common locations: metaphysis of the knee and distal tibia


  • Imaging features:



    • Radiographic features: eccentric metaphyseal lesion with well-defined sclerotic margins. Calcifications seen in 12%, more common in those aged more than 40 years.


    • CT: eccentric metaphyseal lesion with well-defined sclerotic margins. Calcifications easily appreciated.


    • MRI: well-defined lesion with uniform low intensity on T1-weighted and high or intermediate intensity on T2-weighted sequences


  • Differential diagnosis:



    • Fibrous defect


    • Fibrous dysplasia


    • Chondroblastoma


    • Aneurysmal bone cyst


  • Treatment: curettage and bone grafting






FIGURE 9-15. Chondromyxoid fibroma. Anteroposterior (AP) radiograph of the left lower leg (A) shows a lucent lesion (arrow) in the proximal tibial diaphysis with sclerotic septations. Axial computed tomography (CT) image (B) shows a soft tissue density mass replacing the normal marrow fat density with no matrix calcifications and causing endosteal scalloping (arrow). The vertical sclerotic septation seen on radiograph is at the anterior aspect of the mass (arrowhead). Axial T1-weighted (C), fat-saturated T2-weighted (D), and postcontrast fat-saturated T1-weighted (E) images show a central area of nonenhancing cystic change. The peripheral tissue demonstrates T1 isointensity to muscle, heterogeneous T2 hyperintensity, and enhancement.







FIGURE 9-15. (continued)



SUGGESTED READING

Cappelle S, Pans S, Sciot R. Imaging features of chondromyxoid fibroma: report of 15 cases and literature review. Br J Radiol. 2016;20160088. [Epub ahead of print]

Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41(10):1195-1212.

Rahimi A, Beabout JW, Ivens JC, et al. Chondromyxoid fibroma: a clinicopathological study of 76 cases. Cancer. 1972;30:726-736.

Yamaguchi T, Dorfman HD. Radiographic and histologic patterns of calcification in chondromyxoid fibroma. Skeletal Radiol. 1998;27:559-564.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: NONOSSIFYING FIBROMA


KEY FACTS



  • Clinical:



    • Nonossifying fibroma, fibrous cortical defect, and fibroxanthoma describe similar metaphyseal or metadiaphyseal lesions. Lesions are common and typically discovered incidentally.


  • Age: 5 to 35 years, peak second decade


  • Sex: no sex predilection


  • Common locations: distal femur, distal tibia


  • Imaging features:



    • Radiographic features: well-defined eccentric lytic defect with scalloped sclerotic margins in the metaphysis or metadiaphysis of a long bone


    • CT: well-defined eccentric lytic defect with scalloped sclerotic margins in the metaphysis or metadiaphysis of a long bone


    • MRI: well-defined cortical lesion with low to intermediate intensity on T1-weighted and low to intermediate signal intensity on T2-weighted sequences


  • Differential diagnosis:



    • Fibrous dysplasia


    • Chondromyxoid fibroma


    • Eosinophilic granuloma


  • Treatment: none unless potential for pathologic fracture






FIGURE 9-16. Nonossifying fibroma. Anteroposterior (AP) (A) and lateral (B) radiographs show an eccentric, geographic, mildly expansile lucent lesion in the distal femoral diaphysis with sclerotic septation and well-defined sclerotic margins (arrows). The lesion is largely hypointense on both coronal T1-weighted (C) and fat-saturated T2-weighted (D) magnetic resonance (MR) images, but has a thin T1- and T2-hyperintense rim (arrows) of tissue immediately subjacent to the T1- and T2-hypointense margin (arrowheads).







FIGURE 9-16. (continued)



SUGGESTED READING

Jee W, Choe B, Kang H, et al. Nonossifying fibroma: characteristics at MR imaging with pathologic correlation. Radiology. 1998;209:197-202.

Wootton-Gorges SL. MR imaging of primary bone tumors and tumor-like conditions in children. Magn Reson Imaging Clin N Am. 2009;17(3):469-487.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: SOLITARY BONE CYST


KEY FACTS



  • Also known as a simple bone cyst or unicameral bone cyst


  • Clinical:



    • Patients are asymptomatic unless pathologic fracture occurs.


  • Age: first two decades


  • Sex: Males outnumber females in the ratio 3:1.


  • Common locations: proximal humerus, femur, or tibia (90% in humerus or femur)


  • Imaging features:



    • Radiographic features: well-defined lytic lesion frequently near the physis. May have internal septations. If fracture has occurred, the “fallen fragment sign” (bone fragment in the dependent portion of the cyst) is virtually pathognomonic.


    • CT: fluid density, well-defined lesion with or without bony septations


    • MRI: uniformly iso- to low intensity on T1-weighted and high intensity on T2-weighted sequences. Internal septations may be seen. Fluid-fluid level or “fallen fragment” after fracture.


  • Differential diagnosis:



    • Aneurysmal bone cyst


    • Fibrous dysplasia


  • Treatment: aspiration and steroid injection. If in a weight-bearing region, consider curettage and bone grafting.






FIGURE 9-17. Unicameral bone cyst. Anteroposterior (AP) radiograph (A) of the right knee shows an eccentric, geographic, mildly expansile lucent lesion in the proximal tibial metaphysis with a thin sclerotic margin (arrows). Coronal short-TI inversion recovery (STIR) (B) magnetic resonance (MR) image demonstrates homogeneous hyperintensity compatible with a fluid-filled cyst. Axial postcontrast fat-saturated T1-weighted image (C) demonstrates a thin rim of peripheral enhancement (arrow).







FIGURE 9-17. (continued)






FIGURE 9-18. Unicameral bone cyst. Anteroposterior (AP) radiograph of the humerus demonstrates a bone cyst with pathologic fracture and the associated “fallen fragment sign” (arrows).



SUGGESTED READING

Conway WF, Hayes CW. Miscellaneous lesions of the bone. Radiol Clin North Am. 1993;31:299-323.

Kileen K. The fallen fragment sign. Radiology. 1998;207:261-262.

Mascard E, Gomez-Brouchet A, Lambot K. Bone cysts: unicameral and aneurysmal bone cyst. Orthop Traumatol Surg Res. 2015;101(1 suppl):S119-S127.

Wootton-Gorges SL. MR imaging of primary bone tumors and tumor-like conditions in children. Magn Reson Imaging Clin N Am. 2009;17(3):469-487.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: ANEURYSMAL BONE CYST


KEY FACTS



  • Clinical:



    • Patients present with pain.


  • Age: 5 to 35 years, 80% in the first two decades


  • Sex: Females slightly outnumber males.


  • Common locations: more than 50% in the long bones; 12% to 30% in the spine


  • Imaging features:



    • Radiographic features: eccentric lytic lesion with expanded or “ballooned” bony contour. Sclerotic rim and periosteal response are common.


    • CT: same features as radiographs but with fluid-fluid levels of varying fluid density reflective of varying blood product age


    • MRI: well-defined expansile lesion with fluid-fluid levels of varying T1 and T2 intensity reflective of varying blood product age


  • Differential diagnosis:



    • Bone cyst


    • Giant cell tumor


    • Osteoblastoma (vertebral location)


  • Treatment: curettage and bone grafting







FIGURE 9-19. Aneurysmal bone cyst. Anteroposterior (AP) radiograph (A) shows an eccentric expansile lucent lesion (arrows) in the distal tibia with thin septations. The lesion demonstrates several discrete areas of variable T1 hyperintensity on the coronal T1-weighted magnetic resonance (MR) image (B), which reflects blood products of varying age. Axial fat-saturated T2-weighted MR image (C) demonstrates a septated cystic lesion with a fluid-fluid level (arrow).



SUGGESTED READING

Mascard E, Gomez-Brouchet A, Lambot K. Bone cysts: unicameral and aneurysmal bone cyst. Orthop Traumatol Surg Res. 2015;101(1 suppl):S119-S127.

Munk PL, Helms CA, Holt RG, et al. MR imaging of aneurysmal bone cysts. Am J Roentgenol. 1989;153:99-101.

Wootton-Gorges SL. MR imaging of primary bone tumors and tumor-like conditions in children. Magn Reson Imaging Clin N Am. 2009;17(3):469-487.



▪ BONE TUMORS/TUMORLIKE CONDITIONS: FIBROUS DYSPLASIA


KEY FACTS



  • Clinical:



    • Typically asymptomatic. Abnormal bone growth may cause deformity. Lesions may be single (monostotic) in which case the femur, tibia, ribs, and skull base are most commonly involved. Multiple lesions (polyostotic) involve one side of the skeleton in 90% of patients. These lesions are more often symptomatic and may enlarge until skeletal maturity.


  • Associated syndromes:



    • Mazabraud syndrome: fibrous dysplasia and multiple intramuscular myxomas


    • Albright-McCune: females with polyostotic dysplasia, skin lesions, and precocious puberty


  • Age: most often second or third decade


  • Sex: slightly more common in females


  • Common locations: skull, mandible, ribs, femoral neck, tibia


  • Imaging features:



    • Radiographic features: metaphyseal or diaphyseal lytic or “ground glass” density with sharp margins and bone expansion. May affect multiple bones in approximately 15% of patients. “Long lesion in long bone.”


    • CT: well-defined lesion with sclerotic margins


    • MRI: well-defined lesion with low-intensity margins. Low signal intensity on T1-weighted and intermediate signal intensity on T2-weighted sequences.


  • Differential diagnosis:



    • Nonossifying fibroma


    • Bone cyst


    • Aneurysmal bone cyst


    • Chondromyxoid fibroma


  • Treatment: observation






FIGURE 9-20. Fibrous dysplasia. Anteroposterior (AP) radiograph of the left humerus demonstrates a long mildly expansile lucent lesion with “ground-glass” density involving nearly the entire length of the bone. There is a well-defined thin sclerotic margin distally (arrow).







FIGURE 9-21. Mazabraud syndrome. Anteroposterior (AP) radiograph (A) of the right hip and femur demonstrates fibrous dysplasia in the right ilium and proximal femoral diaphysis (arrows). Coronal short-TI inversion recovery magnetic resonance (STIR MR) image (B) of both thighs demonstrates the right-sided lesions seen on radiograph as well as one in the contralateral left femur (arrows). There are also homogeneous T2-hyperintense soft tissue masses compatible with myxomas in the right thigh and left lateral hip region (arrowheads).



SUGGESTED READING

Bousson V, Rey-Jouvin C, Laredo JD, et al. Fibrous dysplasia and McCune-Albright syndrome: imaging for positive and differential diagnoses, prognosis, and follow-up guidelines. Eur J Radiol. 2014;83(10):1828-1842.

Campanacci M, Laus M. Osteofibrous dysplasia of the tibia and fibula. J Bone Joint Surg. 1981;63A:367-375.

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▪ BONE TUMORS/TUMORLIKE CONDITIONS: GIANT CELL TUMOR


KEY FACTS



  • Clinical:



    • Giant cell tumors account for 22.7% of benign bone tumors. Patients present with pain and swelling in the involved site. A tender palpable mass commonly present.


  • Age: 20 to 40 years


  • Sex: females affected slightly more frequently than males


  • Common locations: Most involve the distal femur or proximal tibia (46%) followed by the distal radius and sacrum. Arise in the metaphysis. Eventually extend into the epiphysis and to the subchondral cortex of the adjacent articular surface.


  • Imaging features:



    • Radiographic features: lytic lesion with nonsclerotic margins originating in the metaphysis but extending to subchondral bone. Cortical breakthrough in 33% to 50% of cases.


    • CT: similar to radiographs. No tumor matrix.


    • MRI: iso- to slightly higher signal intensity relative to muscle on T1-weighted and intermediate signal on T2-weighted sequences. T2 sequences may show decreased signal because of hemosiderin deposition. In some cases, signal intensity increased on T2-weighted images. May have secondary aneurysmal bone cyst formation with fluid-fluid levels. Enhances with postcontrast images.


  • Differential diagnosis:



    • Chondroblastoma


    • Osteosarcoma


    • Fibrosarcoma


    • Malignant fibrous histiocytoma


  • Treatment: resection with grafting or, in some cases, joint prosthesis






FIGURE 9-22. Giant cell tumor. Anteroposterior (AP) radiograph (A) of the left knee demonstrates a geographic lucent lesion with a nonsclerotic margin (arrow) involving the distal femoral metaphysis. The coronal T1-weighted magnetic resonance (MR) image (B) better demonstrates the distal aspect of the lesion crossing the physeal scar (arrowhead) and involving the epiphysis.







FIGURE 9-23. Giant cell tumor. Oblique radiograph (A) of the left wrist demonstrates a geographic lucent lesion (arrow) with a nonsclerotic margin involving the distal radial metaphysis and epiphysis. Coronal computed tomography (CT) image (B) better delineates the homogeneous soft tissue density lesion and the associated cortical thinning. The lesion shows homogeneous mild hyperintensity relative to muscle on the coronal T1-weighted magnetic resonance (MR) image (C) and heterogeneous T2 hyperintensity on the coronal fat-saturated T2-weighted MR image (D). There is edema-like signal in the surrounding marrow and adjacent soft tissues.

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Sep 22, 2018 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Musculoskeletal Neoplasms
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