very very important topic for radiological residents as well as consultant in everyday radiology

1. GIANT CELL TUMOR
The most
common sites are
the distal femur,
proximal tibia,
distal radius, and
proximal
humerus, in
decreasing order
of incidence.

2. GIANT CELL TUMOR
Involvement of
the distal radius
carries a more
serious
prognosis
because most of
these lesions
are malignant.

3. GIANT CELL TUMOR
The sacrum is
the most
common spinal
site,
representing 8%
of cases. Giant
cell tumor is the
most common
benign tumor of
the sacrum.

4. GIANT CELL TUMOR
Spinal sites
above the sacrum
are rare. Other
infrequent sites
are the
calcaneus,
innominate, rib,
carpal bones,
and patella.

5. GIANT CELL TUMOR
Patellar neoplastic disease is
uncommon; however, most
patellar tumors are benign
(73%) and are cartilaginous in
origin (chondroblastomas or
enchondromas) or giant cell
tumors. Giant cell tumor is the
most common neoplasm of the
patella. Rarely, metastatic
disease from any origin may
affect the patella; this is the
most common cause for
malignancy in the patella.

6. GIANT CELL TUMOR
Tumor usually begins
in the metaphyseal
end of a long bone in
or adjacent to
ossified epiphyseal
line. It usually
extends to the end of
a long bone, abutting
its joint surface,
leaving the lesion
subarticular.

7. GIANT CELL TUMOR
The radiographic
appearance of giant
cell tumor is
characteristic. It is an
eccentric, metaphyseal,
multilobed radiolucent
lesion of a long bone. In
an adult, it is located
adjacent to the
articular surface of the
bone (subarticular).

8. GIANT CELL TUMOR
It is also subarticular
in flat bones,
occurring near the
sacroiliac joint and
acetabulum in the
innominate. Cortex is
thinned and expanded,
and endosteal margins
show a wide zone of
transition, suggesting
a malignant lesion.

9. GIANT CELL TUMOR
The lesion may
traverse the entire
shaft in a relatively
thin bone, such as
the fibula or ulna. A
delicate periosteal
reaction may
develop, independent
of infractions of
cortex.

10. GIANT CELL TUMOR
This sharply
circumscribed
lesion often
expands bone,
with a rather
characteristic
soap bubble
pattern.

11. GIANT CELL TUMOR
Most cases are purely lytic (60%),
and the soap bubble pattern is
present in 40% of cases. These
bubbles and delineating lines are
really reactive trabeculae of bone
formed by appositional bone
growth and do not actually
chamber the lesion because of
their peripheral location. Thus the
giant cell tumor, removing
numerous trabeculae by its
neoplastic growth, prompts
reinforcement of the remaining
trabeculae, resulting in the soap
bubble pattern.

12. GIANT CELL TUMOR
Involvement of flat
bones, such as the
ilium, rib, and
sacrum,
demonstrate the
same roentgen
appearance of an
expanding,
radiolucent, soap
bubble lesion.

13. GIANT CELL TUMOR
If the tumor is
very aggressive, a
purely lytic
radiolucent lesion
will be seen with
cortical
breakthrough and
development of a
soft tissue mass.

14. GIANT CELL TUMOR
Spinal involvement above the
sacrum with expansion and lytic
destruction of a vertebral body or
neural arch is usually called an
osteoblastoma or ABC
radiographically, before biopsy.
Cervical and lumbar spine are the
most common sites. Radiologist
alone cannot predict with any
accuracy whether the giant cell
tumor is benign or malignant.

15. GIANT CELL TUMOR
GCT may also have
aggressive features,
such as a wide zone
of transition, cortical
thinning, expansile
remodeling, or even
cortical bone
destruction and an
associated soft-tissue
mass

16. GIANT CELL TUMOR
GCT within an apophysis. Lytic
lesion with a nonsclerotic
margin in the greater
trochanter. Expansile
component with only a thin rim
of peripheral cortex remaining.
Pathologic analysis
demonstrated a GCT. The
greater trochanter is an
epiphyseal equivalent, and GCT
can occur in this location. When
GCT affects an apophysis, it
does not typically extend to the
subchondral bone.