Radiology - Dr. Salah - Lecture 5 - Bone Diseases
Bone diseases
Bone disease can be divided into:
1. focal: lytic, sclerotic or mixed, solitary or multiple
2. generalized; where all the bones show diffuse increase or decease in bone density
3. alteration in the trabecular pattern or changes in the shape
Solitary bone lesions
They can be lytic, sclerotic, or mixed.
Radiological approach for diagnosis of solitary bone lesions
1st try to decide whether the lesion is benign (i.e. stable or very slow growing) or
whether the lesion is aggressive (malignant tumor or infection)
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1. Age of the patient
This can be an extremely important determinant in some lesions in which the age range of
occurrence may be quite narrow. For example,
Malignant osseous lesions in patients:
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•
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Under one year; metastatic neuroblastoma
Age range of 1 to 30 years; osteosarcoma or Ewing's sarcoma
In the 30- to 60-years range; chondrosarcoma, primary lymphoma, or malignant
fibrous histiocytoma
Age range over 50 ; metastatic disease or multiple myeloma
2. Location of the lesion
ypes of locations should be noted:
Three different types
a. the particular bone that is involved. ( long bone ,flat bone , small bones)
b. the location in a transverse axis. (central, eccentric, or a cortically
cortically-based
based epicenter).
c. the location in a longitudinal axis of a long bone. (e
(epiphysis,
piphysis, metaphysis or
diaphysis).
sion occur at the certain sites, ee.g.
.g. Osteomyelitis characteristically occur in the
Certain lesion
metaphyseal areas specially of the knee & lower tibia whereas giant cell tumor occur in
subarticular areas.
3. Zone of transition
i.e. Zone of transition of the lesion from abnormal to normal bone; A wide zone of transition
transitio
denotes an aggressive lesion. A narrow zone is a much less aggressive lesion. Well defined
sclerotic edge is almost certainly benign.
4. Adjacent cortex
Any destruction
estruction of the adjacent cortex indicates an aggressive lesion such as a malignant
tumor or osteomyelitis.
5. Expansion
Bone expansion with an intact well formed cortex usually indicate a slow growing lesion
such as an encondroma or fibrous dysplasia.
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6. Periosteal reaction
Presence of an active periosteal reaction in the absence of the trauma usually indicates an
aggressive lesion
7. Soft tissue involvement
Cortical breakthrough of a bone lesion to create a soft tissue mass generally suggest an
aggressive lesion (infection or tumor). Ill-defined soft tissue swelling adjacent to focal bone
disruction lesion suggest infection. Well define soft tissue swelling adjacent to the bone
lesion suggest neoplasm& such soft tissue masses will often distort but not obliterate nearby
muscle planes.
8. Pattern of bone destruction
Common terminology includes ;
a. "geographic" (well-defined or map-like lesion, the least aggressive pattern),
b. "moth-eaten" (holes, with less well-defined margins, appearing more aggressive)
c. "permeative" (a poorly demarcated pattern which is often very difficult to visualize
and represents a highly aggressive lesion)
9. Calcific densities within the lesion (tumor marix)
They allow categorization of a lesion as bone producing versus cartilage producing. Diffuse
ill defined calcification within the lesion suggest osteoid lesion. Presence of a patchy
calcification of popcorn or stippled type with density more than normal bone usually
indicate cartilagenous tumor.
10. Size of the lesion
Generally, a larger lesion (greater than 5 cm) is more likely to be malignant or aggressive,
but there are many exceptions to this statement, and other determinants are generally more
important than this one.
11. Polyostotic versus Monostotic
This is the last most important point , since polyostotic lesions automatically restrict the
number of disease processes that might be considered. For example,
Nonaggressive polyostotic lesions should be confined to;
a.
b.
c.
d.
e.
fibrous dysplasia
Paget's disease
Histiocytosis
multiple exostosis
multiple enchondromatosis
Aggressive polyostotic lesions would be confined to
a.
b.
c.
d.
osseous metastases
multiple myeloma
primary bone tumor with osseous metastases,
multifocal osteomyelitis, aggressive histiocytosis, and multifocal vascular bone
tumors.
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Bone Tumors
Primary bone tumors
1- malignant
2- benign
Secondary bone tumors
Investigations;
1- plain film radiography in general is the best imaging technique for making the Dx.
2- MRI&CT often shows the full extend of the tumor & show the effects on the surrounding
structures& the relation ship to the neurovascular bundles
3- Isotope scan is used for detecting multiplicities of the diseases process & to Dx metastatic
bone disease
PRIMARY MALIGNANT BONE TUMORS - RADIOLOGICAL CRITERIA
1- plain radiograph; usually they have:
Poorly defined margin.
Wide zone of transition.
Lesion may destroy the cortex.
Periosteal reaction is often present.
Soft tissue mass may be seen.
2- Isotope scan: Malignant bone tumor show increased activity in the lesion.
3-MRI: MRI is the most accurate technique in showing the local extend of the tumor with the
advantage that images may be produced in coronal & sagittal planes & MRI provides this
information better than CT
Osteosarcoma (osteogenic sarcoma)
Age ; mainly 5-20 years but also seen in elderly following malignant transformation of
paget’s disease.
Location; Is often arise in the metaphysis, most commonly around the knee joint.
X-ray finding; often there is bone destruction & new bone formation with typical florid
speculated periosteal reaction (sunray appearance). The tumor may elevate periosteum to
form Codman’s triangle
Chondrosarcoma
Age; 30-60 years
Site; most common sites are pelvic bones, scapulae, humeri & femora
Radigraphic finding; It produce lytic expansile lesion contains flecks of calcification. It can be
difficult to be distinguished from its benign counterpart (enchndroma), but condrosarcoma
usually less well defined in at least one portion of its outline & may show a periosteal
reaction & soft tissue component. Chondrosarcoma may arise from malignant degeneration
of the benign cartilaginous tumors.
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Ewing sarcoma
Is a highly malignant tumor.
Age; most commonly occur in the children ,usually between 5-15 years.
site; it arise mostly in the long bone, usually in diaphyseal region.
X-ray finding; It produce an ill define bone destruction with periosteal reaction that is
typically onion skin in appearance.
Giant cell tumor
Has features of both malignant & benign tumor, it is locally invasive but rarely metastasizes.
Age; usually 20-40 years.
site; it is most commonly occur around the knee & wrist after the epiphysis have fused.
X-ray finding; Expanding destructive lesion which is subarticular in position. the margin is
fairly well defined but the cortex is thin & may be in places completely destroyed.
BENIGN BONE TUMORS
COMMON X-RAY FINDING;
Narrow zone of transition with sclerotic rim.
Cause expansion but rarely produce cortical breakdown .
periosteal reaction is unusual unless there is has been a fracture through the lesion.
There is no soft tissue mass .
Isotope scan;
shows little or no increase in the activity unless fracture has been occurred through the
lesion.
MRI & CT scan: are rarely needed in their evaluation
Enchndroma
Are seen as lytic expanding lesion .
Most commonly seen in the hand.
They often contain flecks of calcium & frequently present as a pathological fracture.
Fibrous dysplasia
May affect one or more bone.
It occur most commonly in the long bones& ribs.
Radiologically it appear as lucent area with a well-defined edge and may expand the bone,
there may be sclerotic rim around the lesion.
Simple bone cyst
Occurs in children & young adult.
Most common sites are humerus & femur
X-ray; Lucency across the width of the shaft of the bone with well defined edge. The cortex
may be thin & the bone expanded. Often the 1st clinical finding is pathological fracture
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Aneurysmal bone cyst
are neoplasm.
Mostly seen in children & young adult.
Common sites; spine, long bone & pelvis.
Radiological finding; X-ray; purely lytic & cause massive bone expansion. CT & MRI may show
the blood pool within the cyst. Major differential Dx is Giant cell tumor
Oseoid osteoma
Is a painful condition found most commonly in the femur & tibia in young adults.
Radiological appearance; it has a characteristic appearance;
Small lucency sometime with central specks of calcification (nidus) surrounded by dense
sclerotic rim & periosteal reaction may be seen.
Osteomyelitis
Usually occur in infant& children.
Initial radiographic appearance is normal & bone changes are not visible until 10-14 days of
the infection.
Most sensitive imaging modalities are isotope scan & MRI which may shows the disease
within 1-2 days.
Acute oseomyelitis
Typically affect metaphysis of the long bone.
X-ray finding;
The earliest sign on the plain radiograph is soft tissue swelling with characteristic
obliteration of fat plains & may be apparent with 1st 2 days of the clinical manifestations.
local osteoporosis may be seen within 10-14 days of the onset of the symptoms.
bone destruction in the metaphysis with periosteal reaction that eventually may become
very extensive & surround the bone to form involucrum which is usually visualized after 3
weeks.
Part from the original bone may die & separate to form dense fragment called sequestrum.
Isotope scan; increased activity in both early & delay phase.
MRI; is the investigation of choice & may shows evidence of bone marrow edema & pus
accumulation in the bone & soft tissue
Chronic oseomyelitis
The bone become thickened & loss differentiation between the cortex & the medulla
TB osteomyelitis
Spine is the most common site followed by large joints, but any bone may be affected.
The disease produce large areas of bone destruction & unlike pyogenic infection, the disease
is relatively asymptomatic in the early stage.
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