Pediatric Benign Bone Tumors: What Does the Radiologist Need to Know? - PowerPoint Presentation

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Pediatric Benign Bone Tumors: What Does the Radiologist Need to Know?

Jignesh N. Shah, MD1; Harris L. Cohen, MD2; Asim F. Choudhri, MD3; Saurabh Gupta, MD4; Stephen F. Miller, MD5

Department of Radiology, Le Bonheur Children’s Hospital, University of Tennessee Health Science Center, Memphis, Tenn1,2,3,5; Department of Radiology, Children’s Hospital of Philadelphia, Philadelphia Pa4

Presented as an education exhibit at the 2015 RSNA Annual Meeting. Exhibit: PD148-ED-X

Corresponding author: Jignesh N. Shah, MD University of Tennessee Health Science Center848 Adams Avenue, Radiology G216, Memphis, TN 38103Phone: (901) 287-6938 Fax: (901) 287-5147E mail: jshah3@uthsc.edu

All authors have disclosed no relevant financial relationships.

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INTRODUCTION

Primary benign bone tumors are more common than malignancies in children and adolescents.Patient age and lesion location are two critical factors when evaluating for a bone tumor.Radiography is the mainstay and is a cost-effective imaging modality. Cross-sectional imaging is helpful in tissue characterization and for evaluating the extent of the lesions.

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LEARNING OBJECTIVES

To review classification and pathogenesis of pediatric benign bone tumorsTo discuss the role of radiography and cross-sectional imaging to diagnose benign bone tumors and guide management To describe clinical and imaging features of systemic syndromes associated with benign bone tumors in children

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DIAGNOSTIC CHECKLIST TO EVALUATE BONE LESIONS ON RADIOGRAPHS

AgeLocationNumber of lesionsLesion matrixMargin featuresPresence or absence of periosteal reactionPresence or absence of extraosseous extension

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Matrix or tissue

Benign tumors Cystic lesionsUnicameral (simple) bone cyst, aneurysmal bone cystOsseous matrixEnostosis, osteoma, osteoid osteoma, osteoblastomaChondroid matrixEnchondroma, chondroblastoma, chondromyxoid fibroma, osteochondroma, juxtacortical chondromaFibro-osseousNonossifying fibroma, fibrous dysplasia,

osteofibrous dysplasiaFat LipomaVascular malformationsHemangiomaGiant cell tumorsGiant cell tumorOthersLangerhans cell histiocytosisCLASSIFICATION OF PEDIATRIC BENIGN BONE TUMORS ACCORDING TO MATRIX OR TISSUE TYPE

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RADIOLOGIC APPROACH TO BENIGN BONE TUMORS—LOCATION OF THE LESION

Location within the long boneBenign tumorCommon locations in skeletonUnicameral bone cystproximal humerus, proximal femur, calcaneusAneurysmal bone cysttibia, femur, fibula, spineOsteoid osteomafemur, tibia, spine, tarsalsOsteoblastomaspine, tarsal bone (calcaneus), femurEnchondroma

phalanges, femur, humerus, metacarpalsChondroblastomafemur, humerus, tibiaChondromyxoid fibromatibia, femur, tarsal boneOsteochondromafemur, humerus, tibia, fibulaNonossifying fibromatibia, femur, fibula, humerusFibrous dysplasia

femur, tibia, rib, skull, humerus

LipomacalcaneusHemangiomaspine, ribs, craniofacial bonesGiant cell tumorfemur, tibia, fibula, humerus, distal radius

Eosinophilic granuloma

femur, skull, iliac bone, rib, vertebra

ABC = aneurysmal bone cyst, GCT = giant cell tumor,

NOF =

nonossifying

fibroma, SBC = simple bone cyst

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CENTRIC

ECCENTRICCORTICALJUXTACORTICALSimple bone cyst, eosinophilic granuloma, fibrous dysplasia, aneurysmal bone cyst, and enchondroma Chondroblastoma, chondromyxoid fibroma, giant cell tumor, and osteoblastomaNonossifying fibroma, osteoid osteomaOsteochondroma,

juxtacortical chondromaRADIOLOGIC APPROACH TO BENIGN BONE TUMORS—LOCATION IN THE LONG BONESRADIOLOGIC APPROACH TO BONE TUMORS AND TUMORLIKE CONDITIONS—POLYOSTOTIC LESIONSMnemonic FEEMHI: fibrous dysplasia, enchondroma, eosinophilic granuloma, metastases, hyperparathyroidism, infection

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CYSTIC LESIONS: SIMPLE BONE CYST

Radiograph shows well-demarcated lucent lesion in the proximal humerus with endosteal scalloping: simple bone cyst.Radiograph shows fallen fragment sign (arrow): after pathologic fracture.Axial short inversion time inversion-recovery (STIR) magnetic resonance (MR) image through right proximal femur shows high signal intensity without fluid-fluid levels.Sagittal STIR MR image shows internal trabeculation in humeral simple bone cyst, which can happen after fracture.Treatment options: None if asymptomatic; intralesional steroids for large cysts; surgery with curettage and bone graftingLocation: Intramedullary, metaphysis of long bones, abutting the growth plate; most commonly in proximal humerus and proximal femur 

ABCD

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CYSTIC LESIONS: ANEURYSMAL BONE CYST

Radiograph shows sharply defined, expansile radiolucent lesion with thin mineralized margins in proximal tibia.Axial STIR MR image shows fluid-fluid levels representing areas of blood of variable age.Coronal STIR MR image shows secondary aneurysmal bone cyst (arrow) in a patient with fibrous dysplasia; other causes of secondary aneurysmal bone cyst: chondroblastoma, giant cell tumor, osteosarcoma. Axial bone algorithm computed tomographic (CT) image shows expansile left iliac bone aneurysmal bone cyst.Location: Eccentric in metaphysis of long bones (50%–60%), spine and sacrum (20%–30%)Treatment options: Curettage and bone grafting, with a recurrence rate of 12%–30%

1ABCDPathologic finding: aneurysmal bone cysts consist of blood-filled nonendothelialized spaces separated by connective tissue of bone or osteoid tissue and osteoclast giant cells. 1Lin et al, Clinical Orthopaedics and Related Research 2008;466(3):722-728.

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BONE-FORMING TUMORS: ENOSTOSIS

Enostosis is a benign focus of compact (cortical) bone located in the cancellous bone (medullary cavity).Location: Pelvis, long bones, ribs, and spine are most common.Frontal radiograph (left) and axial bone algorithm CT image (right) through the proximal femur demonstrate a well-circumscribed dense lesion in the medullary cavity (arrows): enostosis.Treatment: No-touch lesionFrontal radiograph of pelvis demonstrates multiple bone islands (arrows): osteopoikilosis.

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BONE-FORMING TUMORS: OSTEOMA

Treatment: Excise only if they cause complications (eg, mucocele) or mass effect (functional or cosmetic impairment).Osteomas are benign lesions consisting of mature bone tissue, seen almost exclusively in bones preformed in membrane. Multiple osteomas can be seen in Gardner syndrome.Location: Paranasal sinuses (75% overall), skull vault, and mandibleRadiograph shows right frontal osteoma (arrow).Coronal CT image shows left ethmoid osteoma (arrow) with mass effect with orbit and obstruction of ostiomeatal complex.Axial CT image shows ossified mass in right ethmoid sinus: osteoma (arrow).

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BONE-FORMING TUMORS: OSTEOID OSTEOMA

Calcaneal osteoid osteoma (arrow): Lateral radiograph (A) and sagittal bone algorithm CT image (B) show reactive mineralization around the lucent central nidus, which is less than 2 cm in diameter (osteoblastoma if nidus is >2 cm); CT is the modality of choice for confirmation, as well as localization of nidus, and helps to guide ablation.Scintigraphic findings may show double-density sign, which is the central focus showing intense uptake within a surrounding lower-uptake rim.Treatment: Fluoroscopic image shows unroofing with intralesional excision-curettage of the nidus, as in this case of calcaneal osteoid osteoma (arrow); other options include percutaneous radiofrequency ablation. Axial STIR MR image shows T2- hyperintense nidus (arrow) with surrounding marrow edema in left acetabulum: osteoid osteoma.Location: Cortical diaphyseal location (65%–70%), commonly in femur; spine in 10% of casesClassically manifests with nocturnal pain, relieved by aspirin

AB

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BONE-FORMING TUMORS: OSTEOBLASTOMA

Axial bone algorithm CT image shows expansile lucent lesion (>2 cm in size) with rim of mineralization: thoracic spinal osteoblastoma (arrow).Location: Spinal column, in particular posterior elements (40%–55%); metaphysis and distal diaphysis of long bones (26%)Insidious dull pain that gets worse at night and minimal response to salicylates (unlike osteoid osteoma)Biopsy is often required to differentiate it from osteosarcoma (if the lesion involves long bone).Treatment options: Radical surgical excision; preoperative embolization to reduce bleeding risk; percutaneous ablationAxial precontrast T1-weighted (A) and sagittal postcontrast T1-weighted fat-saturated (B) MR images show expansile mass involving posterior elements of upper thoracic vertebra with isointensity on T1-weighted images (A) and postcontrast enhancement (B) with cord compression. Arrows = osteoblastoma.

AB

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CARTILAGE-FORMING TUMORS: ENCHONDROMA

Location: Medullary cavity of tubular bonesPathogenesis: Arise from rests of growth plate cartilage and/or chondrocytes that subsequently proliferate and slowly enlarge and are composed of mature hyaline cartilageRadiographs show expansile lucent lesion in the middle phalanx with cortical thinning: enchondroma with pathologic fracture.Radiographs show proximal humeral (A) and metacarpal (B) lesions with ring and arc pattern of chondroid mineralization: enchondroma (arrow).ABTreatment options:

None for small incidental lesions; marginal and/or wide resection for large symptomatic lesions; sarcoma follow-up if histologic finding shows low-grade chondrosarcoma.

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OLLIER DISEASE

Nonhereditary, sporadic, skeletal disorder characterized by multiple enchondromas that are principally located in the metaphyseal regions; if associated soft-tissue hemangiomas, it is termed Maffucci syndrome.25%–30% risk of chondrosarcoma at 40 years2Radiograph shows vertical streaks of lucencies (columnar configuration) in metaphysis of long bones, extending to the epiphysis.Treatment: Corrective surgery if growth impairment, deformity (such as leg-length discrepancy)Radiograph shows multiple expansile lucent lesions involving hand bones with sharply defined scalloped margins: enchondromas.Radiograph shows right iliac bone enchondroma.2

Zwenneke et al. RadioGraphics 2001;21(5):1311-1316.

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METACHONDROMATOSIS

Multiple striated metaphyseal enchondromas (arrows)Multiple osteochondromas (arrows) pointing toward the joint and often involving bones of hands and feet (unlike classic osteochondromas)Periarticular calcification (arrow)3Very rare condition; approximately 50 cases reported in literature

Most exostotic lesions typically regress by skeletal maturity (unlike diaphyseal aclasis)3Fisher et al. Journal of Children’s Orthopaedics 2013;7(6):455-464.

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CARTILAGE-FORMING TUMORS: CHONDROBLASTOMA

Location: More than 75% in long bones, epiphyseal in origin, which often extends to metaphysisPathologic finding: They are composed of chondroblasts, chondroid matrix. Calcium deposition surrounding the polyhedral chondroblasts has been described as a "chicken-wire calcification” pattern.Radiographic features: Well-defined epiphyseal lucent lesions (arrows), with either smooth or lobulated margins and a thin mineralized rim.Coronal T2-weighted STIR (left) and sagittal T1-weighted (right) MR images show T2 hypointensity, surrounding edema, and absence of transphyseal extension.Treatment options: Curettage and packing with bone grafting; radiofrequency ablation 

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CARTILAGE-FORMING TUMORS: CHONDROMYXOID FIBROMA

Radiographic features: Lobulated, eccentric radiolucent lesion in the metaphysis with long axis parallel to long axis of long bone, geographic bone destruction, well-defined mineralized margin, may contain septations: chondromyxoid fibroma (arrows).Pathogenesis: Lobular lesion with variable amounts of myxoid, chondroid, and fibrous tissue componentsMR images show high signal intensity on STIR image (A) with peripheral enhancement (B).ABTreatment: Curettage, but high recurrence rate of 25%; if possible, en bloc resection

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CARTILAGE-FORMING TUMORS: OSTEOCHONDROMA

Any bone that develops from preformed cartilage (enchondral ossification) may develop an osteochondroma.Pedunculated (narrow-based) osteochondromaThe lesion is composed of cortical and medullary bone protruding from and continuous with the underlying bone.Sessile (broad-based) osteochondromaMR image to look for mass effect and evaluate the hyaline cartilage cap (T2- hyperintense structure indicated by arrows) 

Findings to suggest degeneration to chondrosarcoma: osseous destruction, change in calcification pattern, enlargement of cartilage cap of more than 1.5 cm4, new painNonmalignant complications: fracture, traction on soft tissues and/or nerves, vascular complications, adventitial bursal formation 4Murphey et al. RadioGraphics 2000;20(5):1407-1434

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DIAPHYSEAL ACLASIS

Also known as hereditary multiple exostoses, which demonstrates an autosomal dominant inheritance pattern; 90% have positive family history for multiple exostoses. Treatment: Watchful waiting; biopsy if there is growth after the adjacent growth plate closure; remove exostoses causing complications and if cartilage cap is more than 1.5 cm (approximately 3%–5% risk for developing chondrosarcoma4)There is symmetric widening of metaphyses with multiple small and large multilobulated exostoses arising from normal underlying bone: diaphyseal aclasis.4Murphey et al. RadioGraphics 2000;20(5):1407-1434

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TREVOR DISEASE:

Dysplasia epiphysealis hemimelica Extremely rare nonhereditary disease; osteochondromas arising from the epiphyses; affects one in 1,000,000 of the populationClinical types: localized: when one epiphysis is involved; classic: more than one epiphysis is affected in one limb (the most common presentation); generalized: affecting entire limbRadiographs: irregular mass with focal ossification arising from one side of the affected epiphysis Treatment: surgical excision of mass; preservation of jointRadiograph shows exostosis (arrow) from right humeral epiphysis. Radiograph, CT image, and three-dimensional reconstruction of exostosis from talus (arrows).

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CARTILAGE-FORMING TUMORS: JUXTACORTICAL CHONDROMA

Common locations: Diametaphysis of proximal humerus and distal femurRadiographs show well-defined distal femoral diametaphyseal lucent lesion (arrows) with underlying cortical saucerization or scalloping and subjacent cortical mineralization.Axial T2-weighted STIR (A) and axial postcontrast T1-weighted fat-saturated (B) MR images show a well-marginated, cortically based lesion with internal hyperintense T2 signal and peripheral rim enhancement.Treatment: Curettage or local excisionAB

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FIBRO-OSSEOUS LESIONS: FIBROUS CORTICAL DEFECT

Radiographs show eccentric cortically based lucent lesion (arrows) with mineralized rim; no involvement of the underlying medullary cavity; no periosteal reaction.Treatment: No-touch lesionMost common benign bone lesionLocation: Usually metaphysis or diametaphyseal junction of the distal femur or proximal or distal tibiaSagittal T2-weighted fat-saturated (left) and axial T1-weighted (right) MR images show hypointensity (arrow) at T1 and hyperintensity (arrow) at T2; signal intensity depends on stage of healing.

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FIBRO-OSSEOUS LESIONS: NONOSSIFYING FIBROMARadiographs show sharply demarcated, multilobulated, asymmetrical, cortically based lucent lesion with a thin mineralized rim: distal tibial nonossifying fibroma.A larger version (>3 cm) of a fibrous cortical defectCoronal T2-weighted STIR MR image shows peripheral low-signal-intensity rim (arrows) that corresponds to the mineralized border.Treatment: Do not touch lesion. If large (involving more than 50% of the diameter of the parent bone), then prophylactic curettage and bone grafting may be prudent to avoid a pathologic fracture.Radiograph after curettage and bone grafting.

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MULTIPLE NONOSSIFYING Fibroma: JAFFE-CAMPANACCI SYNDROME

Jaffe-Campanacci is a rare syndrome characterized by the association of café au lait spots, axillary freckles, and multiple nonossifying fibromas of the long bones and jaw, as well as some features of type 1 neurofibromatosis.The risk for pathologic fracture is more than 50% because of substantial cortical thinning of the weight-bearing bones.Radiographs show multiple nonossifying fibromas (arrows).Radiograph shows pathologic fracture (arrow).

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FIBRO-OSSEOUS LESIONS: FIBROUS DYSPLASIA

Nonneoplastic tumorlike congenital process, manifesting as a localized defect in osteoblastic differentiation and maturation, with replacement of normal bone with large fibrous stroma and islands of immature woven boneCT images show ground-glass matrix; well-circumscribed; no periosteal reaction: fibrous dysplasia (arrows).CT images show bowing deformity, “shepherd’s crook” deformity, of femoral neck.Treatment: None, as the bone lesions usually do not progress beyond puberty. Treat if complicated by pathologic fracture. If mass effect is severe, then surgical decompression.Risk of malignant transformation: 1% in mono-ostotic form; 4% in polyostotic form5 especially in patients with McCune-Albright syndrome, Mazabraud syndrome, or prior radiation exposure

5Riddle et al. Archives of Pathology & Laboratory Medicine 2012;137(1):134-138.

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Nonhereditary phakomatosis that primarily affects female patients and is characterized by the triad of polyostotic fibrous dysplasia, café au

lait macules, and endocrine dysfunctionPOLYOSTOTIC FIBROUS DYSPLASIA: McCUNE-ALBRIGHT SYNDROMERadiograph (left) and axial bone algorithm CT image (right) show ground-glass appearance of distal humerus, proximal radius and ulna, and skull.Radiograph shows extensive polyostotic fibrous dysplasia with deformities.

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FIBRO-OSSEOUS LESIONS: OSTEOFIBROUS DYSPLASIA

Location: Tibial diaphysis most common (80%), mainly the anterior cortexPathologic finding: There are randomly distributed lamellated bone spicules on a background of fibrous stroma. Frontal (A) and lateral (B) radiographs of tibia and fibula demonstrate a multiloculated lucent ground-glass lesion with a mineralized margin and cortical expansion; note tibial bowing and pseudoarthrosis after a pathologic fracture (arrow); no periosteal reaction.ABTreatment options: Tissue diagnosis is essential to differentiate this lesion from adamantinoma. Once the diagnosis is made, wide resection for large lesions after puberty may reduce the rate of recurrence.

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FIBRO-OSSEOUS LESIONS: CEMENTO-OSSIFYING FIBROMA

Benign fibro-osseous lesion composed of encapsulated mixture of fibrous tissue and mature bone; arise in tooth-bearing areasLocation: Most common craniofacial site is the mandible, 10%–20% involve maxillaCoronal soft-tissue algorithm (A) and axial bone algorithm (B) CT images demonstrate a well-demarcated expansile soft-tissue attenuating (indicating fibrous center) sinonasal mass with ossified rim and central attenuation characteristics suggesting fibrous tissue.ABCoronal T1-weighted MR image shows heterogeneous intermediate T1 signal intensity due to fibrous components.

Treatment: Complete surgical resection

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GIANT CELL TUMOR

Also known as osteoclastoma; rare in skeletally immature patients (80% of cases occur between 20 and 50 years; fewer than 3% of cases occur before the age of 14 years)Location: Commonly around knee and distal radiusPathogenesis: Overexpression in RANK-RANKL (receptor activator of nuclear factor kappa-B ligand) signaling pathway with resultant overproliferation and/or recruitment of osteoclastsRadiographs show well-defined eccentric epimetaphyseal lesion; occurs after growth plate closure; abuts articular surface; nonmineralized margin; note pathologic fracture (arrow).Treatment: Curettage and packing with bone chips or polymethylmethacrylate; denosumab, an antagonist to rankl, may be offered in advanced giant cell tumor to reduce skeletal morbidity.Isointense to skeletal muscle on T1-weighted (A) and heterogenously hyperintense on T2-weighted (B) MR images: tibial giant cell tumor.

AB

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FAT-containing LESIONS: lipomaCT image shows fat-containing well-defined lesion with central ossification.Location: Most frequently in calcaneus; metaphysis of long bonesPathologic finding: Mature adipocytes without admixed hematopoietic tissue or bone trabeculaeRadiograph shows radiolucent bone lesion with well-defined margins and internal mineralization.Intraosseous lipomas in calcaneus

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VASCULAR

MALFORMATIONS: HEMANGIOMACT image shows well-circumscribed hypoattenuating lesion with coarse vertical trabeculae polka-dot appearance. Location: Most frequently seen in the vertebrae or skull.Vertebral hemangiomas are actually venous malformations.Sagittal T1-weighted (A) and T2-weighted (B) MR images demonstrate a circumscribed T1- and T2- hyperintense lesion in the body of thoracic vertebra: classic MR appearance of hemangioma.Complications: Pathologic compression fracture; epidural extension with cord compressionTreatment: None if asymptomatic

AB

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IMAGING FEATURES TO DIFFERENTIATE

MIMICsSimple bone cystFibrous dysplasiaPredominant locationMetaphysisDiaphysisMatrix LucentGround glassClassic radiographic signFallen fragment signShepherd’s crook deformityMR imaging appearanceCysticHeterogeneousChondroblastomaGiant cell tumorPredominant locationEpiphysisMetaphysis Age of the patientSkeletally immatureSkeletally matureMarginsMineralized Nonmineralized generallyMatrixMay have chondroid matrix

Absence of matrixNonossifying fibromaChondromyxoid fibromaPredominant locationMetadiaphysisMetaphysisLocation within the boneCortically basedEccentric intramedullaryTreatmentNo-touch lesion, undergoes mineralization eventuallyMarginal excision (curettage and bone grafting)

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TUMOR MIMICS: EOSINOPHILIC GRANULOMA

Location: Skull most common (50%), mandible, ribs, femur, pelvis, spinePathologic finding: There is abnormal proliferation of Langerhans cells with an abundance of eosinophils, lymphocytes, and neutrophils. These cells produce prostaglandins, which result in medullary bone resorption.Skull radiograph (left) and axial bone algorithm CT image (right) demonstrate a punched-out lucent lesion without a mineralized rim; double-contour or bevelled-edge appearance (arrow) is due to greater involvement of the inner than the outer table.Collapsed L5 vertebral body (vertebra plana) (arrow) with sparing of disk space on radiograph (left) and sagittal T1-weighted MR image (right).Treatment: Usually undergoes spontaneous resolution; if symptoms persist, excision and curettageWhole-body positron emission tomography/CT can be useful for detection of polyostotic disease and to monitor response to therapy.

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TUMOR MIMICS: INFECTION (BRODIE ABSCESS)

Intraosseous abscess related to focus of subacute pyogenic osteomyelitis; most common organism, Staphylococcus aureusLocation: Metaphysis of long bones, most commonly in proximal or distal tibiaMR image: penumbra sign (arrow) indicates a rim of vascularized granulation tissue lining of the abscess cavity with higher signal intensity than that of the main abscess fluid collection on T1-weighted images.Radiograph shows lucent lesion (arrow) with mineralized rim in the metaphysis of distal tibia.Axial CT (A) and T1-weighted MR (B) images show left pubic Brodie abscess. Note MR imaging penumbra sign (arrow).

Treatment options: Surgical curettage, bone grafting and antibiotic therapyAB

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BROWN TUMOR IN HYPERPARATHYROIDISM

Pathologic finding: Increased parathyroid hormone causes mobilization of skeletal calcium through rapid osteoclastic turnover of bone, and if the bone loss is rapid, hemorrhage and reparative granulation tissue, with active, vascular, proliferating fibrous tissue, may replace the normal marrow contents, resulting in a brown tumor (so named for histologic appearance of blood products).Also known as osteitis fibrosa cystica; one of the manifestations of hyperparathyroidism, which represents a reparative cellular process rather than a neoplastic process.Radiographs show well-defined, purely lucent lesions; thinning and expansion of cortex; pathologic fracture (white arrow); subperiosteal bone resorption on radial aspect of phalanges (yellow arrow).Ultrasonographic image shows a well-defined hypoechoic solid parathyroid mass: adenoma.

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MELANOTIC NEUROECTODERMAL TUMOR OF INFANCY

Melanotic neuroectodermal tumor of infancy is a rare neoplasm of neural crest origin. It is benign but locally aggressive and tends to occur most often during the first few months of life.Location: 70% occur in the maxilla, followed by the skull (11%) and mandible (6%)Frontal and lateral radiographs of the skull demonstrate hyperostosis (arrows), expansion, and tumoral calcification of the skull involving the posterior parietal and occipital bones. Note that the tumor crosses sutures. Sagittal bone algorithm CT image delineates the margins of hyperostotic tumor.Treatment: Surgical excision with or without chemotherapy for nonresectable cases

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CONCLUSION

Primary benign bone tumors are more common than malignancies in children and adolescents. By paying attention to the age of the patient, location of the lesion, and radiographic characteristics, the radiologist can narrow the differential diagnosis, which helps to guide clinical management, preventing unnecessary patient anxiety and medical intervention.

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SUGGESTED READINGS

Miller TT. Bone tumors and tumorlike conditions: analysis with conventional radiography. Radiology 2008;246(3):662-674.Motamedi K, Seeger LL. Benign bone tumors. Radiol Clin North Am 2011;49(6):1115-1134.van der Woude HJ, Smithuis R. Bone tumor: systematic approach and differential diagnosis. http://www.radiologyassistant.nl/en/p494e15cbf0d8d/bone-tumor-systematic-approach-and-differential-diagnosis.html. Published April 10, 2010. Accessed October 8, 2015.

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REFERENCES

Lin PP, Brown C, Raymond AK, Deavers MT, Yasko AW. Aneurysmal bone cysts recur at juxtaphyseal locations in skeletally immature patients. Clinical Orthopaedics and Related Research. 2008;466(3):722-728.Zwenneke Flach H, Ginai AZ, Wolter Oosterhuis J. Best cases from the AFIP. Maffucci syndrome: radiologic and pathologic findings. RadioGraphics. 2001;21(5):1311-1316.Fisher TJ, Williams N, Morris L, Cundy PJ. Metachondromatosis: more than just multiple osteochondromas. J Child Orthop. 2013;7(6):455-464. Murphey MD, Choi JJ, Kransdorf MJ, Flemming DJ, Gannon FH. Imaging of osteochondroma: variants and complications with radiologic-pathologic correlation. RadioGraphics. 2000;20(5):1407-1434.Riddle ND, Bui MM. Fibrous dysplasia. Archives of Pathology & Laboratory Medicine. 2012;137(1):134-138.