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▪ Abnormal neoplastic bone tissue growth
▪ Benign tumors more common than
▪ Primary tumors: originate from bone (more
▪ Secondary tumors: originate from other
▪ Retinoblastoma, Li–Fraumeni syndrome,
chronic infl ammation, chronic osteomyelitis,
Paget’s disease, bone infarcts, radiation
▪ Usual appearance: long bones (e.g. femur/
tibia), pelvis, vertebra, etc.
▪ Benign tumors usually asymptomatic,
undetected (early stages), discovered by
▪ Palpable mass, structural malformation
▪ Pathological fracture, restricted motion
▪ Benign tumors tend to have more defi ned
▪ Asses relation with other structures
▪ Assess skeletal involvement extent,
▪ Rare malignant tumor; bone, soft tissue
▪ Small, round blue-stained cells; believed to
▪ Translocation fuses two regions together
▫ Friend leukemia insertion (FLI1):
▫ Newly-formed EWS-FLI1 protein:
abnormal transcription factor → induce
cell division, malignant transformation
▪ Usually sporadic; occurs in children, young
▪ ↑ risk, Ewing’s sarcoma family history
▪ Pelvis, femur, clavicle, humerus, ribs, spine
▪ Intense pain (stronger at night);
▪ Soft palpable mass attached to bone; can
compress nerves → function loss (e.g.
urinary incontinence if sacrum involved)
▪ Systemic symptoms: fever, weight loss can
▫ Lung metastases: most signifi cant
▫ Rapid tumor growth raises periosteum
▪ Precise tumor location, size, adjacentstructure relation
Positron emission tomography (PET) scan
Figure 108.1 A histological section of a
classic Ewing’s sarcoma. The tumor cells are
undifferentiated, closely packed and have
vague cytoplasmic borders. There are two
distinct populations of light and dark cells.
▪ Tumor removal/limb amputation
Figure 108.2 An anterior-posterior X-ray of
the left shoulder demonstrating a Ewing’s
Figure 108.3 A PET-CT scan in the coronal
plane demonstrating a Ewing’s sarcoma of
the left proximal femur. The tumor, visible
on CT scan corresponds well with the high
levels of tracer uptake on the PET scan.
osms.it/giant-cell_tumor_of_bone
▫ Destructive growth, metastases
▫ Tumor cells: giant multinucleated cells
▫ Non-tumor cells: osteoclasts, their
▪ Tumor cells express RANKL → binds
to RANK on osteoclasts, precursors
membrane → induce cell division,
▪ ↑ osteoclast number (tumor sometimes
called osteoclastoma) + absence of control
▪ Commonly around knee (distal femur/
▪ Lucent mass; cortical thinning/destruction;
pathological fracture; mineralization,
▪ Homogeneous intensity, well-defi ned
▫ ↑ periphery uptake, ↓ center uptake
Figure 108.4 A anterior-posterior radiograph
of the wrist demonstrating a giant cell tumor
of bone at the subarticular portion of the
radius. It has a characteristic soap bubble
Figure 108.5 The histological appearance
of a giant cell tumor of bone. There are
numerous multinucleated osteoclastic giant
cells surrounded by smaller mononuclear
Figure 108.6 The gross pathological
appearance of a giant cell tumor of bone
▪ Benign bone tissue-forming tumor; similar
▪ Comprises many osteoid (not yet
mineralized bone tissue), fi brous (woven)
▪ May break bone cortex, grow to adjacent
Figure 108.7 The histological appearance of
an osteoblastoma. There is abundant osteoid
and woven bone forming trabeculae which
are lined by a single layer of osteoblasts.
▪ Commonly affects posterior spine, long
▪ Dull pain (exacerbated at night)
▪ Not responsive to salicylates
▪ Structural malformations (e.g. scoliosis)
▪ Spinal cord, nerve compression → pain,
▪ Swelling, tenderness, ↓ range of motion
▪ >2cm/0.79in; no periosteal reaction
(differs from osteoid osteoma); if arising
from cortical bone → thin new bone layer
▪ Assess surrounding structure volume,
Figure 108.8 A CT scan of the lower
leg in the axial plane demonstrating an
▪ Immature trabeculae with single osteoblast
▪ High dilated blood vessel number
▪ Distinguish from osteosarcoma
▫ Does not imbue surrounding bone, soft
▪ Commonly affects lower-extremity long
bones (e.g. femur, tibia), phalanges, spine
▪ Very intense pain (exacerbated at night)
▫ Surrounded by reactive bone,
<2cm/0.79in in size (differs from
osteoblastoma), central mineralization
▪ Pain medications (e.g. salicylates, NSAIDs)
▪ CT scan-guided radiofrequency ablation
▫ Benign, similar to osteoblastoma
▫ Good blood supply, comprised of
osteoblasts providing osteoid, fi brous
▫ Osteoblasts → ↑ prostaglandin E₂ →
▪ Nidus produces/envelopes itself in reactive
Figure 108.9 The histological appearance
of an osteoid osteoma. There is woven bone
surrounded by osteoblasts with numerous
▪ Malignant bone tissue-forming bone tumor
▪ Growth plates with mutation-prone cells
▪ Chromosomal aberrations; oncogenes,
▫ Retinoblastoma gene (RB): cell cycle
▫ Tumor protein 53 (p53): DNA repair, cell
▫ Bone marrow repression, cortical bone
breakage, adjacent-joint spread
Figure 108.10 An X-ray image of the leg
demonstrating a ill-defi ned, radiolucent lesion
at the distal diaphysis and metaphysis of the
femur. The tumor was histologically proven to
▪ Appears in long bones, usually around knee
(e.g. distal femur, proximal tibia)
▪ Pain exacerbated by movement; lowered
motion range; growing palpable mass;
swelling, lymphadenopathy; pathologic
▪ Soft tissue mass with different calcifi cation
▫ Periosteal reaction (tumor mass lifts
▪ Permeative process in bone (endosteum
▪ Assess tumor stage, relation to other
structures → precise surgical removal
▪ Look for metastases → ↑ radionuclide
Figure 108.11 The histological appearance
of an osteosarcoma. There are numerous
malignant spindle cells producing osteoid.
Figure 108.12 An MRI scan of the leg from
the same individual. The tumor is seen to
extend beyond the cortex of the bone.
Figure 108.13 The gross pathological
appearance of an osteosarcoma of the femur.
The tumor is bulky, with a gritty cut surface
▪ Preoperative chemotherapy (neoadjuvant)
▪ Biopsy, histologic fi ndings
▫ Tumor cells produce bone tissue
▫ Cell shape/size differs (big cells with
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