Radiographic and Pathologic Characteristics of Common Bone Neoplasms

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Radiographic and Pathologic Characteristics of
Common Bone Neoplasms

• Nick Luem
• Diagnostic Radiology
• June 24, 2007

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Classification of the more common bone tumors

• Malignant Neoplasms
• Osteogenic sarcoma
• Chondrosarcoma
• Ewings sarcoma

• Benign Neoplasms
• Osteochondroma
• Chondroma
• Giant Cell Tumor
• Aneurysmal Bone Cyst

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Osteochondroma

• Also known as exostosis
• Children and teenagers most affected, Men gtgt
  Women
• Clinically appear as slow growing masses, painful
  if impinging on nerve tissue
• Solitary or multiple
• Multiple Hereditary Exostosis? autosomal dominant
  disease with inactivation of both copies of EXT
  gene in growth plate chondrocytes

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Osteochondroma

• Benign projection of bone with cartilaginous cap
• Occurs in epiphyseal plate and grows laterally
• Exhibits cortex and medullary portion
• May convert to malignancy if cartilage cap
  becomes thicker and contains disorganized
  calcifications
• Conversion to sarcoma rare (lt1) but higher in
  patients with hereditary syndrome

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Osteochondroma

• Ultrasound safe and inexpensive way to evaluate
  thickness of cartilaginous capsule
• Develops in bones of endochondral origin and
  arises from the metaphysis near the growth plate
  of long tubular bones.
• Occasionally develops from bones of the pelvis,
  scapula and ribs
• MRI method of choice to evaluate thicknesss of
  cartilaginous cap to rule out malignant conversion

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- Radiograph can demonstrate that cortex of
osteochondroma blends with cortex of normal
bone - Long axis of tumor usually runs parallel
to parent bone and points away from parent
joint
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Osteochondroma Disorganized growth plate with
endochondral ossification Newly made bone
forms inner portion of head and stalk Medullary
cavity of osteochondroma and bone are
continuous
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Chondroma

• Slow-growing tumor of hyaline cartilage
• Enchondromas?arise within medullary cavity
• Juxtacortical chondroma?arise on bone surface
• Destroys normal bone by erupting as mixture of
  calcified and uncalcified hyaline cartilage
• Occur in children and young adults
• Enchondromas usually solitary
• Favor the metaphyseal region of tubular bones
  such as the small bones of the hand and feet

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Chondroma

• Most asymptomatic and found incidentally
• Occasionally cause pathologic fractures
• Ollier disease? syndrome of multiple enchondromas
• Maffuci syndrome?enchondromatosis associated with
  soft tissue hemagiomas
• May recur if incompletely excised

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• Radiographic findings of
• enchondromas include a stippled
• ringlike or arclike calcifications within
• the lucent matrix
• -Cartilage nodules can form
• well-circumscribed oval lucencies
• surrounded by thin rim of radiodense
• bone, the O ring sign
• -T2-weighted MR images show lesion
• with lobulated borders from endosteal
• scalloping and containing focal areas
• of high signal intensity
• Nuclear medicine scans usually
• negative in enchondromas, ruling
• out the possibility of malignancy

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• -Nodules of cartilage that are well-
• circumscribed with a hyaline matrix
• -The neoplastic chondrocytes in the
• lacunae are cytologically benign
• Cartilage at the periphery of the
• nodule undergoes endochondral
• ossification

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Giant Cell Tumor

• Name derives from abundant multinucleated
• osteoclast-type giant cells
• Uncommon but locally aggressive tumor. Usually
  arises in patients in their twenties to forties.
• Giant cell tumors in adults involve both
  epiphyses and metaphyses, but in adolescents are
  confined proximally by the growth plate and are
  limited to the metaphysis
• Majority occur in the distal femur and proximal
  tibia but any bone may be involved
• May cause arthritic symptoms in patients or lead
  to pathologic fractures

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Giant Cell Tumor
Large red to brown tumors that undergo cystic
degeneration
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Giant Cell Tumor

• Conservative surgery, such as curettage,
  associated with 40 to 60 recurrence rate
• Up to 4 metastasize to the lungs
• Some lesions can be pre-malignant or malignant
• MRI used to determine intraarticular extension,
  soft tissue involvement and bone marrow changes
• Diagnostic accuracy high when MR images and X-ray
  images are combined

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• Characteristic radiographic appearance of
• Giant Cell Tumor multiple large bubbles
• separated by thin strips of bone

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Giant Cell Tumor
Tumor is composed of uniform oval mononuclear
cells with indistinct membranes and appear to
grow in a syncytium Scattered within this
background are numerous osteoclast-type giant
cells Necrosis, hemorrhage, hemosiderin depositio
n and reactive bone formation are frequent
secondary features
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Aneurysmal Bone Cyst

• Not a true neoplasm or cyst
• Numerous blood filled arteriovenous
  communications
• Thought to be secondary to trauma
• Often mistaken for malignant tumor on plain
  radiograph

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Aneurysmal Bone Cyst

• CT can show the lobulations of the lesion
• MRI shows internal loculation and fluid levels
  that produce low signal on T2-weighted images
• T1-weighted images show cyst with a low to
  intermediate signal intensity. Signal intensity
  increases if acute hemorrhage present

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Aneurysmal Bone Cyst

• Expansile, eccentric, cystlike
• lesion that causes pronounced
• ballooning of thinned cortex in
• long bones
• Cystic lesion has multiple, fine
• internal septa

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Aneurysmal Bone Cyst
Microscopically, the ABC has cystic spaces filled
with blood. The fibrous septa have immature woven
bone trabeculae as well as capillaries hemosideri
n-laden macrophages, fibroblasts, and giant cells.
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Malignant neoplasms

• Osteosarcoma
• Chondrosarcoma
• Ewings Sarcoma

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Osteosarcoma

• Malignant mesenchymal tumor in which cancerous
  cells produce bone matrix
• Accounts for approximately 20 of primary bone
  cancers
• Bimodal age distribution 75 occur in patients
  lt20 years. Second peak occurs in older adults who
  have known conditions associated with the
  development of osteosarcoma (Paget disease, bone
  infarcts, prior irradiation)
• Metaphyseal region of long bones common site,
  roughly 60 occur about the knee

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Osteosarcoma

• Patient with hereditary retinoblastomas have up
  to 1000 times greater risk of developing
  osteosarcoma
• Attributed to germ line mutations in RB gene
• Abnormalities in other genes that regulate cell
  cycling implicated (CDK4, p16, INK4A, CYCLIN D1,
  MDM2)
• Typically present as painful and progressively
  enlarging masses. At time of diagnosis, aprox.
  10-20 of patients have metastates to the lungs

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Osteosarcoma
Reactive periosteal bone forms when tumor breaks
through cortex This leaves a triangular shadow
between the cortex and raised ends of periosteum
known radiographically as Codman triangle
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Osteosarcoma
Tan-white tumor fills most of the medullary
cavity of the metaphysis and proximal
diaphysis The tumor infiltrates through
the cortex, lifts the periosteum and forms soft
tissue masses on the side of the bone Several
subtypes are recognized and grouped by location,
degree of differentiation, multicentricity and
histologic variance
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Osteosarcoma
Coarse, lacelike pattern of neoplastic
bone formed by anaplastic malignant tumor cells.
Bone may be deposited in large sheets of
primitive trabeculae
Cartilage and fibrous tissue may be present in
varying amounts. Vascular invasion
usually conspicuous and spontaneous necrosis is
common
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Chondrosarcoma
Chondrosarcomas produce neoplastic cartilage Seco
nd most common malignant matrix-producing tumor
of bone Subclassified by Site?intramedullary,
juxtacortical Histology?conventional, clear
cell, dedifferentiated, mesenchymal variant
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Patients usually gt40 yrs of age Men affected
twice as frequently as women Commonly arise in
central portions of skeleton pelvis,shoulder and
ribs. Clear cell variant originates in the
epiphyses of long tubular bones Often contain
punctate or amorphous calcification within its
cartilaginous matrix Endosteal scalloping and
cortical destruction seen radiographically The
more radiolucent the tumor, the greater
likelihood of a higher grade
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Chondrosarcoma
Tumors vary in degree of cellularity, cytologic
atypia and mitotic activity Low grade mild
hypercellularity, plump vesicular nuclei with
small nucleoli, and sparse mitotic figures
High grade extreme pleomorphism with bizarre
tumor giant cells and mitoses
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Ewings Sarcoma

• Small round cell tumor of bone
• Accounts for 6-10 of primary malignant bone
  tumors
• Most patients between 10 to 15 years old
  youngest average age at presentation of all bone
  tumors
• Treatment includes chemotherapy and surgical
  excision. At least 50 are cured long term

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• Classic radiographic appearance
• Ill-defined permeative area of bone destruction
• Involves large central portion of the shaft of a
• long bone
• Ewing sarcoma typically arises in the
• medullary cavity and invades
• the cortex and periosteum
• Associated with a fusiform layered periosteal
• reaction parallel to the shaft,
• the classic Onionskin appearance

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Tumor composed of sheets of uniform,small,
round cells that are slightly larger than
lymphocytes with scant cytoplasm Generally
little stroma and necrosis maybe
prominent Relatively few mitotic figures in
relation to the dense cellularity of the tumor
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References

• Robbins and Cotran, Pathologic Basis of Disease
  7th Edition. Elsevier Saunders, Philadelphia, PA
• Eisenberg, Comprehensive Radiographic Pathology
  4th Edition. Mosby, St. Louis, MO
• Grainger Allisons Diagnostic Radiology A
  Textbook of Medical Imaging 4th Edition.