benign bone tumors an approach
TRANSCRIPT
Dr . Rafeevudh Dharaja
BENIGN BONE TUMORS – AN APPROACH
الرحمن الله بسمالرحيم
Bone-forming tumors • Osteoid osteoma • Osteoblastoma
Cartilage-forming tumors • Osteochondroma • Chondroma • Chondroblastoma • Chondromyxoid
fibroma
Fibrous lesions • Fibrous dysplasia • Ossifying fibroma • Nonossifying fibroma
Cystic and vascular lesions • Unicameral bone cyst • Aneurysmal bone cyst
CHARACTERISTICS OF BENIGN LESIONS
• Well-defined or sclerotic border
• Sharp zone of transition • Small size or multiple
lesions • Confinement by natural
barriers (eg, growth plate, cortex)
• Lack of destruction of the cortex
• Lack of extension into the soft tissue
APPROACHAge at Presentation• Primary bone tumours are rare below the age of 5
years and over the age of 40 years.
• Osteoid osteoma • Osteobastoma• Enchondroma • Chondroblastoma- teenage• Chonromyxoid fibroma• ABC• FD – before 30 yrs•
• Solitary or multiple?• Which bone affected? e.g.
long bone vs. spine• Where is the lesion in the
bone?• Well-defined margins?• Cortical destruction?• Bony reaction?• Central calcification?• Look also at the soft
tissues.
• Enchondromatosis• FD• Adamantinoma
KEY QUESTIONS TO ASK OURSELVES • Posterior elements of
spine - Osteoblatoma-• Metacarpals and
phalanges - Enchonromatosis -
• Calcaneum - Interosseous lipoma-
• Humerus - Simple bone cyst
• Tibial anterior cortex- adamantinoma
• Epiphysis – chondroblastoma• Metaphysis – CMF, ABC• Diaphsis – LCH, SBC• Medullary cavity –
enchondroma CMF, FD• Surface of cortex - periosteal
chondroma• Cortex- fibrous cortical defect
• Solitary or multiple?• What type of bone, e.g. long bone vs. spine vs.
ribs?• Where is the lesion in the bone?• Well-defined margins?• Cortical destruction?• Bony reaction?• Central calcification?• Look also at the soft tissues.
Lesion margin• In benign and low-grade
malignant neoplasms, this margin is sharp - geographical; Type 1
Type 1A has a rim of sclerosis between the lesion and the host bone Type 1B is a very well defined lytic lesion but with no marginal sclerosis Type 1C has a slightly less sharp, nonsclerotic margin
Type 2 - moth-eaten destruction, characterised by multiple lucent areas measuring 2–5 mm in diameter separated by bone which has yet to be destroyed Moth-eaten- caused by the coalescence of multiple small lytic areas. Type 3 - is permeative destruction, which is the most aggressive pattern - composed of multiple coalescing small ill-defined lesions of 1 mm or less in diameter with a zone of transition of several centimetres
AP radiograph of the ilium reveals the classic moth-hole appearance (arrows) of moth-eaten destruction
AP radiograph of the ilium shows the typical diffuse, ill-defined appearance of permeative destruction.
• Solitary or multiple?• What type of bone, e.g. long bone vs. spine vs.
ribs?• Where is the lesion in the bone?• Well-defined margins?• Trabeculated?• What type of matrix ?• Cortical destruction?• Bony reaction?• Central calcification?• Look also at the soft tissues.
Matrix Mineralisation
• Chondral calcifications are typically linear, curvilinear, ring-like, punctate or nodular
• Osseous mineralisation is cloudlike and poorly defined
• Diffuse matrix mineralisation in benign fibrous tumours produces the characteristic ‘ground-glass’ appearance
Typical punctate chondral calcification in grade 11 chondrosarcoma
‘cloud-like’ osseous mineralisation in patient with osteoblastic osteosarcoma
Fibrous dysplasia showing typical ‘ground-glass’ mineralisation
• Solitary or multiple?• What type of bone, e.g. long
bone vs. spine vs. ribs?• Where is the lesion in the
bone?• Well-defined margins?• Trabeculated?• Cortical destruction?• Bony reaction?• Central calcification?• Look also at the soft tissues.
• GCT• CMF• ABC• NOF
GCT
• Solitary or multiple?• What type of bone, e.g. long bone vs. spine vs.
ribs?• Where is the lesion in the bone?• Well-defined margins?• Cortical destruction?• Bony reaction?• Central calcification?• Look also at the soft tissues.
Periosteal Reaction• Solid periosteal reaction
- slow rate of growth but not necessarily a benign tumour- OO, chondroblastoma
• Laminated periosteal reaction - subperiosteal extension of tumour, infection or haematoma. Lesions demonstrating periodic growth may show a multi-laminated pattern
• Solitary or multiple?• What type of bone, e.g.
long bone vs. spine vs. ribs?
• Where is the lesion in the bone?
• Well-defined margins?• Cortical destruction?• Bony reaction?• Central calcification/ lytic
nidus• soft tissue reaction?
• Osteoid osteoma• osteoblastoma
• Chondroblastoma
PLAIN RADIOGRAPHS
• Best initial modality • Should include views in
2 planes • 80 – 90 % of cases can
be diagnosed • Advanced imaging
should not be necessary for clearly benign lesions
In other places
FOR BONE LESIONS
Further imaging essential if malignancy a possibility:• Bone scan will identify other lesions.• CT identifies bony architecture.• MRI gives invaluable soft tissue and bony
information, particularly tumour extent.
Cartilage tumours Osteochondroma Chondroma Enchondroma Periosteal chondromas Multiple chondromatosis Chondroblastoma Chondromyxoid fibroma
CARTILAGE TUMOURS Osteochondroma
Age • Highest incidence is in the second decade.
Location• Long bones are commonly affected, especially
around the knee (~40%)• Commonest locations - distal femur, proximal
humerus, proximal tibia and proximal femur.• The commonest flat bones affected are the ilium
and scapula
• Continuity between the medullary cavity of the lesion and that of the underlying bone is essential for the diagnosis
• Cartilage cap is optimally demonstrated on axial proton density-weighted (PDW) or T2W fast spin-echo (FSE) MRI
• It should not exceed 2-cm thickness in adults
• Outgrowth from the normal cortex, with which it is continuous
• Pedunculated lesions have a long slim neck
• Sessile lesions have a broad base from the bone of origin
Diaphyseal aclasis:• Hereditary multiple
exostoses,HME• Uncommon autosomal
dominant disorder• Exostoses may be
larger than the solitary variety
• The metaphyses in this condition are also typically widened and dysplastic
Complications:• Bursa formation• Neurovascular compromise• Pseudoaneurysm
ENCHONDROMA• Intramedullary neoplasm comprising lobules of
benign hyaline cartilage• Enchondromas affect the tubular bones of the
hands and feet in 40–65% of cases • Proximal phalanges (40–50%),• Followed by the metacarpals (15–30%) and • Middle phalanges (20–30%).
Patients present due to• Increasing size• Pathological fracture• Or incidental finding
RADIOLOGICAL FEATURES• Most enchondromas arise
centrally in the phalanges and metacarpals
• Well-circumscribed, lobular or oval lytic lesions, which may expand the cortex
• Chondral-type mineralisationmay be present
• Enchondroma protuberans- eccentrically placed enchondroma with associated extraosseous component covered by a thin shell of intact cortical bone
Lobular, mildly expansile lesion with typical chondral matrix mineralisation
Eccentrically placed enchondroma of the fourth toe proximal phalanx (arrowhead) with an associatedextraosseous component covered by a thin cortical shell
Large enchondroma or a grade 1 chondrosarcoma??• Lesion size above 5–6 cm
and deep endosteal scalloping are suggestive of chondrosarcoma
Low-grade chondral tumours- MRI features• Lobular margin with
intermediate T1-weighted signal intensity
• T2-weighted-hyperintensity without surrounding reactive oedema
ENCHONDROMATOSIS
Multiple enchondromas, with expansion of the proximal right femur
Maffucci’s Syndrome• Multiple enchondromas and soft-tissue
haemangiomas
CHONDROBLASTOMA• Between the ages of 5 and 25 years (mean age ~20
years).Location• Around knee• Proximal humerus• Proximal femur• Eccentrically in the epiphysis (40%), but with
partial closure of the growth plate it usually extends into the metaphysis (55%)
• Commonest tumour of the patella• Presents as monoarthropathy, since it is typically
located in the epiphysis of a long bone,
Radiological Features• Lobular with a fine
sclerotic margin, measuring 1–4 cm in size
• Matrix mineralisation is demonstrated in ~30%
• Linear metaphyseal periosteal reaction is present in almost 60% of long bone cases
• MRI shows intermediate T1W SI
• Variable SI on T2W images
• Associated marrow and soft-tissue oedema and reactive joint effusion
• Rarely associated with metastases (especially to the lung)
• Rare variant termed ‘aggressive’ (atypical) chondroblastoma, associated with cortical destruction and soft-tissue extension
CHONDROMYXOID FIBROMA• Between 10 and 30 years of age (mean age 25
years).• Long bones -60% of cases, • 40% arising in the flat bones (ilium 10%) or • Small tubular bones of the hands and feet
(17%).
25% of all chondromyxoid fibromas- upper third of the tibia
• Diagnosis – mainly depends on location
• In the proximal tibia eccentric, lobular bubbly lesion with a sclerotic margin
RADIOLOGICAL FEATURESEccentric lytic lesion with a sclerotic margin and expansion of the anterior cortex.
Osteogenic tumours Osteoid osteoma Osteoblastoma
OSTEOGENIC TUMOURS
Osteoid Osteoma (OO)
• Characteristic clinical picture of night pain relieved by aspirin
• Second and third decades of life• Occurs anywhere in appendicular skeleton• Most common in the appendicular skeleton,
with over 50% located in the diaphysis or metaphysis of the tibia or femur
• The characteristic feature of OO is the nidus, which may appear lytic, sclerotic or most commonly of mixed density depending upon the degree of central mineralisation.
• Nidus measures up to 15 mm in diameter and is commonly surrounded by a region of reactive medullary sclerosis and solid periosteal reaction.
• CT demonstrates the classical features of a round or oval soft-tissue density nidus, which commonly shows central dense mineralisation
• Vascular groove sign - thin, serpentine channels in the thickened bone surrounding the nidus
MR- heterogenously low–intermediate SI on both T1W and T2W images enhancing strongly with contrast
Edema-like marrow and soft-tissue SI is almost invariably seen adjacent to the nidus.
• Intra-articular lesions are most commonly seen in the hip
• Present with local osteopenia due to disuse• Soft-tissue oedema-like changes and a joint effusion
• In the ankle and foot -subperiosteal region of the talar neck is a classical site
OSTEOBLASTOMA• Histological similarities to OO and is
differentiated primarily by its size, greater than 1.5 cm in diameter.
• More aggressive growth pattern with potential for extraosseous extension, and does not resolve spontaneously.
• Under the age of 30 years • Common location is the posterior column of the spine • Tumors in the spine may be difficult to identify on plain
radiographs
• Humerus is the commonest location in the appendicular skeleton
• The lesion arises in the medullary cavity
RADIOLOGICAL FEATURES• Predominantly lytic lesions
measuring over 2 cm in diameter
• Larger lesions showing a greater degree of matrix mineralisation
• CT – occult calcification, which can be punctate, nodular or generalised
• Larger lesions may result in bone expansion
• MRI - low–intermediate SI lesion with associated reactive changes as seen with OO, but of a lesser intensity
Large mixed lytic-sclerotic lesion in the medullary cavity with associated periosteal thickening
Fibrogenic tumours Desmoplastic fibroma Fibrohistiocytic tumour Benign fibrous hystiocytoma Fibrous cortical defect Non ossifying fibroma
FIBROGENIC TUMOURS Desmoplastic Fibroma
• Rare, locally aggressive benign neoplasm• Similar histological features to soft-tissue
fibromatosis.• Between 10 and 30 years of age (mean age 21
years)• Usually arises in the metaphyseal region of long
bones (femur, humerus, tibia and radius constitute 56% of cases), the mandible (26%) and ilium (14%)
• Rarely associated with fibrous dysplasia
RADIOLOGICAL FEATURES
• Most lesions are metadiaphyseal and arise as either subperiosteal or intraosseous tumours.
• Many are large at presentation (over 5 cm in diameter)
• Two patterns are seen: an ill-defined moth-eaten or permeative lesion an expanding, trabeculated lesion
Expansile aggressive metaphyseallesion
FIBROHISTIOCYTIC TUMOURS
• Fibrous cortical defect,• Non-ossifying fibroma and• Benign fibrous histiocytoma
Identical histological appearances Different in their clinical and radiological features.
• As an incidental finding, in the distal femoral and proximal tibial metaphyses
• Cortically based lytic lesion commonly with a thin sclerotic margin
• Consolidates/fades with time
FIBROUS CORTICAL DEFECT
• Commonly identified incidentally
• May present with pathological fracture when large enough
• In the second decade of life
• Majority involve the lower limbs, particularly the tibia and distal end of the femur
NON-OSSIFYING FIBROMA
Lobular lesion (arrows) expanding the distal fibular metadiaphysis
Axial PDW FSE and coronal T2W FSE MR images showing a lobular lesion (arrows) containing prominent areas of hypointensity due to its fibrous nature.
Jaffe–Campanacci syndrome• Multiple (usually unilateral) NOFs with café-
au-lait spots
Radiological Features
• Metaphyseal or diametaphyseal and essentially intracortical
• Lobular appearance is classical• Lesion usually enlarging into the
medullary cavity.• Long axis in the line of the bone• When NOF arises in a slim bone such
as the fibula, it crosses the shaft readily and its characteristic intracortical origin is less obvious
• Low–intermediate SI on T1W and PDW images and enhances with contrast
BENIGN FIBROUS HISTIOCYTOMA• Uncommon lesion occurring in an older age
group• Between 20 and 50 years, with a mean age in the
third decade
Radiological Features• Lesion resembles a giant cell tumour• Eccentric subarticular location, but with a well-
defined sclerotic margin indicating slower growth
Giant cell tumour Giant cell tumour
Vascular tumours Haemangioma
Smooth muscle tumours Leiomyoma
Lipogenic tumours Lipoma
Neural tumours Neurilemmoma
GIANT CELL TUMOUR• Aggressive benign neoplasm• Between 18 and 45 years of age• Always occurs in a subarticular or
subcortical region• Adjacent to a fused apophysis of
a long bone - with the knee (distal femur/proximal tibia—55%), distal radius (10%) and proximal humerus (6%) being the commonest sites.
RADIOLOGICAL FEATURES• Subarticular, eccentric, lytic
lesion with a geographic, non-sclerotic margin
• Usually measures 5–7 cm in size.
• Apparent trabeculation and cortical expansion are common features
• Cortical destruction with extraosseous extension may occur in up to 50%
Distal radial subarticular lytic lesion (arrows) with internal trabeculation
Eccentric, subarticular lytic lesion of the proximal tibia with a poorly defined margin (arrows) and destruction of the lateral cortex.
• Iso- or hypointense on T1W Images heterogeneous hyperintensity on STIR
• Areas of hyperintensity on T1W indicate the presence of subacute haemorrhage
• Profound hypointensity on T2W images due to the deposition of haemosiderin from chronic recurrent haemorrhage
Sagittal T1W
Important DDs• Lytic osteosarcoma • In older patients, malignant fibrous histiocytoma or • Subarticular lytic metastasis, particularly from a
primary renal tumour.
VASCULAR TUMOURS Haemangioma
Haemangiomas are classified histologically as • Capillary,• Cavernous, • Arteriovenous or • Venous
• Osseous capillary haemangiomas most commonly affect the vertebral body
• Osseous cavernous haemangiomas affect the skull vault• Involvement of the appendicular skeleton is relatively rare
RADIOLOGICAL FEATURES
• Fine or coarse vertical trabeculation is seen involving the epiphyses and metaphyses of long bones, with the direction of the linear striations running along the axis of the bone
• Bone expansion and extraosseous extension are also recognised features
• Scintigraphy typically shows triple-phase uptake due to the vascular nature of the lesion.
Expansile lytic lesion (arrows) containingcoarse trabeculation.
• CT demonstrates the thickened trabeculae as dense ‘dots’ within a fatty matrix
• MRI - intermediate SI on T1W and hyperintense on T2W
Poorly defined lytic lesion containing multiple, dense thickened trabeculae
• Intraosseous Lipoma• Parosteal Lipoma
Intraosseous Lipoma• Arises in the medulla
and produces expansion,• Predilection for the
calcaneus and femur• CT and MRI demostrates
fatty nature of the matrix
LIPOGENIC TUMOURS
well-defined lytic lesion (arrows) in the calcanealbody
Parosteal Lipoma• Rare lesion- most
frequently encountered around the proximal radius
• May result in pressure erosion of the bone and the formation of circumferential juxtacortical new bone.
Axial CT of the elbow showinga fatty mass (arrows) arising in association with a parostealbony lesion (arrowhead) from the proximal radius
Miscellaneous lesions Aneurysmal bone cyst Bone cyst Fibrous dysplasia Osteofibrous dysplasia Langerhans cell histiocytosis (eosinophilic granuloma) Erdheim–Chester disease Chest wall hamartoma
ANEURYSMAL BONE CYST
• Between 5 and 20 years of age• Long bones (>50% of cases) and spine (20%
of cases) are most common• Involvement of flat bones is most common in
the pelvis.• Secondary ABC change can develop in non-
ossifying fibroma, chondroblastoma, giant cell tumour, fibrous dysplasia, osteoblastoma and osteosarcoma.
RADIOLOGICAL FEATURES
• Classical lesion – purely lytic, expansile intramedullary lesion in the metaphysis of a long bone extending to the growth plate which may be centrally or, more commonly eccentrically placed
• A thin ‘egg-shell’ covering of expanded cortex is often identified
Mildly expansile lytic lesion with a thin sclerotic margin (arrows) located eccentrically within the proximal tibial metaphysis
Expansile lesion with a thin sclerotic margin (arrows) arising from the surface of the proximal ulna.
• Heterogeneous intermediate SI on T1W images with internal hypointense internal septa may be seen, which may enhance following administration of gadolinium contrast medium
• T2 or PDW images almost invariably demonstrate multiple FFLs
• Most important differential diagnosis of ABC is telangiectatic osteosarcoma.
• Between the ages of 5 and 15 years
• Presentation with pathological fracture is classical, especially with humeral lesions.
Location• Proximal humerus – most
common • Proximal femur – next
commonOther sites in adults• Calcaneus and • Posterior iiac blade
SIMPLE BONE CYST
Radiological Features• Initially, SBCs are located in the
proximal metaphysis of the humerus or femur and progress toward the diaphysis with skeletal growth, eventually reaching the middiaphysis
• Usually lies centrally in the shaft, expanding the bone symmetrically and thinning the cortex.
• The lesion is typically 6–8 cm in size.
• Apparent trabeculation is common, but periosteal reaction is not seen without fracture,
• Fracture may result in fragment of cortex penetrating the cyst lining, resulting in the fallen fragment sign
MRI• T1W images - low-to-intermediate
SI• Marked hyperintensity on T2W or
STIR images• These appearances are altered by
the presence of fracture, in which case haemorrhage may result in the presence of FFLs and pericystic oedema
Major differential diagnosis• ABC and• Fibrous dysplasia.
• Usually painless• Usually before the age of
30 years• Commonest sites –
monostotic FD – ribs, proximal femur , craniofacial bones
• FD may be associated with a variety of syndromes
• Portions of bone replaced by fibrous connective tissue and poorly formed trabecular bone
Monoostotic • 70 to 85%
Polyostotic• Invt of 2 bones
to more than 75% skeleton
FIBROUS DYSPLASIA
McCune–Albright’s syndrome –• Polyostotic FD (typically unilateral)• Ipsilateral café au lait spots and • Endocrine disturbance, most commonly
precocious puberty in girls
Mazabraud’s syndrome -• FD (most commonly polyostotic) and soft-tissue
myxomata.
Radiological Features• Geographic lesion that may
cause bone expansion and deformity with diffuse ground-glass matrix mineralisation
• A thick sclerotic margin (‘rind’ sign) is characteristic
• Varus deformity of the proximal femur (‘shepherd’s crook’ deformity) is a characteristic late finding.
• Skeletal scintigraphy is the best technique for identifying polyostotic disease
• CT beautifully demonstrates the ground-glass matrix
MRI - isointense on T1Wintermediate SI or hyperintense on T2W,
LANGERHANS CELL HISTIOCYTOSIS (LCH)• Spectrum of disorders characterised by the
idiopathic proliferation of histiocytes (Langerhans cells), which can involve virtually any organ and present either as focal/multifocal lesions
Three forms of the disease• Eosinophilic granuloma,• Letterer–Siwe disease• Hand–Schüller–Christian disease,
• Between the ages of 5 and 15 years
Location• Skull, pelvis, spine, mandible and
ribsRadiological Features• Long bone lesions are usually
located centrally within the diaphysis (~60%), followed by the metaphysis/ metadiaphysis
• Lesions are lytic, showing a fairly aggressive pattern of bone destruction with occasional reactive medullary sclerosis.
• A multi-laminated periosteal response is commonly seen, while endosteal scalloping and mild bone expansion are also features
Irregular lytic lesion (arrows) with a multi-laminatedperiosteal response
BONE ISLAND
• A bone island consists of well-differentiated mature bone tissue within the marrow
• Also referred to as enostosis• Usually it is seen as a coincidental finding.• In patients with breast- or prostate cancer a bone island can be
mistaken for an osteoblastic metastasis.• A bone island normally does not show increased uptake on a
bone scan
Small lytic lesion within the mid tibial diaphysis.
LANGERHANS-CELL HISTIOCYTOSIS
MAFUCCIS’S SYNDROME- HEMANGIOMA AND MULTIPLE ENCHONDROMATOSIS
OSTEOCHONDROMA
POLYOSTOTIC FIBROUS DYSPLASIA
• :TYPICAL GROUND GLASS APPEARANCE. significant expansion of the mid-diaphysis of the tibia and fibula, with the characteristic ground glass appearance tothe matrix of the fibrous dysplastic lesions.
ANEURYSMAL BONE CYST
• Expansile lytic lesion with a thin sclerotic margin located centrally in the metadiaphysis of distal left tibia and extending to the physis. There are subtle internal septations
ANEURYSMAL BONE CYST
SIMPLE BONE CYST
ENCHONDROMA
• Lytic geographic lesion with expansion and chondroid matrix (arrows) are seen on this radiograph of the proximal phalanx of the index finger.
• Distal femur readily shows the coarse dot-like, popcorn-like mineralization of chondroid matrix.