MK4
Giant cell tumor of the bone is a relatively uncommon
tumor usually regarded as benign tumor with local
aggressiveness.
In this work we detail the appearance of this tumor in the
various radiological examinations, namely the standard
radiography, CT and MRI and we describe the signs in
favor of the diagnosis.
We report the case of 3 patients ,explored in our service ,for
tumefaction of periarticular tissues in two cases and bone pain
in 1 case .
All patients had a radiography and MRI . One patient also had
a CT .
Diagnosis raised by radiological exploration, was confirmed
after biopsy of the tumor in all cases.

27-year-old patient

left hip pain for two years with partial functional
imptence .


X RAY
Expansile, osteolytic, radiolucent
lesions without sclerotic margins
and without a periosteal reaction
,located in sacrum .
Intralesionnel septa ,cortical
destruction
, and soft-tissue
masses.
CT
Voluminous expansive process of the left sacral wing responsible for a replacement
cord
with rupture of the anterior
and posterior cortical bone, with significant endopelvi
expansion displacing the rectum to the right side
.
This process extends to the sacral body, measuring 10cm long axis, invaded the joint space
with extension into the controlateral iliac wing
.
On MRI, this process is of mixed
signal, low signal T1, isointense T2,
with areas of hyperintensity and
nodular hyposignal.
AX T2 FAT SAT
SAG T2
Those zones are enhanced in
a heterogeneous way, landscaping
hypointense areas of necrosis
Intraducta extension
encompassing the first sacred
nerve.
Extension to the gluteal region
AX T1
CORO T1 FAT SAT
GADO
•25 old girl
•Painful subcutaneous mass ,adjacent to the left wrist
•Rapid evolution.
•Metaphyseal epiphyseal osteolytic eccentric lesion
,of the distal radius,
with fine internal partitions .
•Extends to the subchondral bone, thinner and blows cortical.
•Compact periosteal reaction and invasion of soft tissues
AX T1
SAG T1
CORO T1
CORO T2
•Epiphyseal metaphyseal expansive
process of the distal let radius.
•Hypointense T1 and T2, enhances
after gadolinium injection.
• Cortical blowing, and replacement
cord
•Breach of the anterior and posterior
cortex with extension to soft tissue .
CORO T1
SAG T1
FAT SAT GADO

34 old patient

Painful subcutaneous mass ,adjacent to the wright wrist.
Ax T1
Ax T2
Ax T2
AXT1 FAT SAT GADO
CORO T1



CORO T1 FAT SAT GADO
Epiphyseal metaphyseal tumor lesion of the right radius, measuring 5.5 x 4.7 cm , with
sharp contours
hypointense on T1and T2, with intense heterogeneous enhancement.
blows the cortical lesion which seems broken in some places and extends to the adjacent
soft tissues
Most giant cell tumors occur in the long bones;
approximately 50% are located in the bones around
the knee.
Location is important in the diagnosis of giant cell
tumor. Most tumors are eccentric and are seen in a
subarticular location ; however, the tumor originates in
the metaphysis, and the common epiphyseal
involvement is the result of the patient's skeletal
maturity .
Early lesions may lie solely in the metaphysis. A
narrow zone of transition with a lack of sclerosis at its
margins is a distinctive finding and strongly suggestive
of the diagnosis.
When sclerosis of the tumor margins is present, it is
seldom complete.
Periosteal reactions are not usually seen; the lack of a
host-reactive response is typical of giant cell tumors.
Giant cell tumors in the spine are uncommon and
account for only 5% of giant cell tumors.
The sacrum is the most common location. Patients
with these tumors tend to be slightly younger than
those with tumors in the appendicular skeleton.
The location in the vertebrae can vary, but the tumor
most commonly involves the vertebral body.
The radiographic appearance of giant cell tumors is often
characteristic. On radiographs, typical giant cell tumors
are usually easily distinguished from other bone tumors.
Giant cell tumors are lytic, subarticular, and eccentric, and
they are often lacking a sclerotic rim; however, unusual
variants may make the radiographic diagnosis difficult.
On radiographs, the tumors may be seen in areas of
destruction of the vertebral body with invasion of the
posterior elements.
The tumor can cause vertebral collapse and spinal cord
compression, especially when it involves the posterior
elements.
The degree of confidence is high for radiography in the
appendicular skeleton.
In the spine, the degree of diagnostic confidence is not
high, as giant cell tumors usually cannot be differentiated
from other types of tumors.
Tumors in the sacrum are recognizable, and these may be
diagnosed on the basis of their appearance and location.
Unusual forms of certain tumors may mimic giant cell
tumors.

Telangiectatic or fibrogenic variants of osteosarcoma
may not produce visible ossifications or calcifications.
These variants may be eccentric and may extend to the
subarticular surface, mimicking a giant cell tumor.

Malignant fibrous histiocytomas occur in a similar age
group and can also mimic a giant cell tumor.

Brown tumors of hyperparathyroidism are well known
in the differential diagnosis of giant cell tumors.

Chondroblastomas may be mistaken for giant cell tumors
because of their subarticular location; however, careful
review of the radiographs usually reveals that the epicenter
lies in the epiphysis rather than in the metaphysis.

The presence of chondroid calcifications further supports
the diagnosis of chondroblastoma.
 Aneurysmal bone cysts may be only slightly expansile in
the early stages, and they can extend to the subarticular
cortex, mimicking a giant cell tumor.
These cysts usually occur in younger patients.

Approximately 29% of aneurysmal bone cysts are
reported to be associated with some other solid bone
lesion, 39% of which are giant cell tumors
CT findings are similar to radiographic findings for
giant cell tumor of bone.
Marginal sclerosis, cortical destruction, and soft-tissue
masses are seen more clearly on CT scans than on
radiographs. Fluid-fluid levels are occasionally seen
but are not specific.
CT does not usually add much diagnostic information to the
radiographic results.
CT scans are more useful in complex-shaped bones, such as
the vertebrae or pelvic bones, because the details of the
lesion may not be depicted well on radiographs.
CT is also useful in surgical planning.
CT scans are usually less useful than are other examinations.
Magnetic resonance imaging (MRI) is sensitive for the
detection of soft-tissue changes, intra-articular extension, and
marrow changes.
MRI is the best method for assessing subchondral
breakthrough and extension of tumor into an adjacent joint.

On T1-weighted images, giant cell tumors may show
heterogeneous or homogeneous signal intensity
characteristics.

The signal intensity is usually low or intermediate, but
areas of high signal intensity, caused by recent hemorrhage,
may be noted.

On T2-weighted images, heterogeneous low to intermediate
signal intensity is seen in solid areas of the tumor . Areas of
low signal intensity may be exaggerated on T2-weighted,
spin-echo images, and these may be even more exaggerated
on gradient-echo weighted images because of the presence
of hemosiderin.

Hemosiderin is detected in more than 63% of giant cell
tumors, and its presence is probably the result of
extravasated red blood cells coupled with the phagocytic
function of the tumor cells.

Cystic areas are common and are seen as areas of high
signal intensity on T2-weighted images. Fluid-fluid
levels may be seen, as in the image below.

Peritumoral edema is uncommon in the absence of a
fracture. The tumor is usually heterogeneously
enhancing with the intravenous administration of
contrast material

The degree of confidence in imaging the appendicular
skeleton is high for MRI. The modality is sensitive in
the detection of soft-tissue changes, intra-articular
extension, and marrow changes.

MRI is the best method for assessing subchondral
breakthrough and the extension of tumor into an
adjacent joint. Its diagnostic accuracy is high,
especially when MRIs are interpreted in conjunction
with plain radiographs.

In the spine, tumors such as osteoblastomas and
aneurysmal bone cysts, as well as metastases, may
be found in the same location as giant cell tumors,
and they may have overlapping MRI characteristics.

The disadvantages of MRI are its relatively high
cost and limited availability. In addition, some patients
experience claustrophobia during the examination and
may require sedation.

MRI is also contraindicated in patients with cardiac
pacemakers , orbital foreign bodies, and
noncompatible anevrysmal clips.

The diagnostic accuracy of MRI is high, especially
when MRIs are interpreted in conjunction with plain
radiographs.
MRI ,when interpreted in conjunction with
radiography enable to suggest the diagnosis of
bone giant cell tumor thanks to its high
diagnostic
accuracy.
The
radiographic
appearance ,although very suggestive diagnosis
,must discuss other etiologies.