Tumors of bone
Tumors of bone
- Cause usually unknown (Primary, idiopathic)
- Genetic factors may play a role (p53 and RB
mutations)
- Bone infarcts, trauma, osteomyelitis, Pagets
disease, radiation and metal prosthesis predispose
to tumors
Tumors of bone
- Clinical presentation
- Incidentally detected
- Swelling and pain
- Pathological fracture
Interpret bone tumors with full knowledge of
- Clinical picture
- Radiology and imaging
- Pathological findings
Tumors of bone
- Diverse in their gross and morphologic features, and
clinical behavior.
- Benign tumors outnumber malignancies and are
commoner in young
- Classification is done on the basis of tissue of origin
Bone tumors
Histologic type
Benign
Hematopoietic (40%)
Malignant
Myeloma, lymphoma
Chondrogenic (22%)
Osteochondroma, chondroma,
chondroblastoma, chondromyxoid fibroma
Chondroscarcoma, dedifferentiated and
mesenchymal chondrosarcoma
Osteogenic (19%)
Osteoid osteoma, osteoblastoma
Osteosarcoma
Unknown (10%)
Giant cell tumor
Ewing sarcoma, giant cell tumor,
adamantinoma
Histiocytic
Fibrous histiocytoma
Malignant fibrous histiocytoma
Fibrogenic
Fibroma
Desomplastic fibroma, fibrosarcoma
Notochordal
Chordoma
Vascular
Hemangioma
Hemangioendothelioma,
hemangiopericytoma, angiosarcoma
Lipogenic
Lipoma
Liposarcoma
Neurogenic
Neurilemmoma (schwannoma)
Tumors and tumor-like conditions of bone
- Diverse in their gross and morphologic features, and clinical
behavior.
- Benign tumors outnumber malignancies and are commoner in
young
- Specific tumor types have preferential age and sex distribution
- Specific tumor types preferentially involve specific bones and
specific regions within a bone
Metaphysis
Osteogenic Sarcoma
10 20 30 40 50 60 70 yrs
Chondrosarcoma
10 20 30 40 50 60 70 yrs
Bone tumors
All bone tumors should be studied along with x rays
- Osteochondroma is the commonest benign tumor
- Osteosarcoma is the commonest non-hematopoietic malignancy
- Specific tumors target specific bones and sites and age groups
- Osteosarcomas are more common in adolescence and arise from
metaphysis around the knee.
- Chondrosarcomas and giant cell tumors arise in epiphysis
- Ewings sarcoma arises in diaphysis
Histologic grade is the most important prognostic factor of a
bone sarcoma
Bone tumors
Histologic type
Benign
Hematopoietic (40%)
Malignant
Myeloma, lymphoma
Chondrogenic (22%)
Osteochondroma, chondroma,
chondroblastoma, chondromyxoid fibroma
Chondroscarcoma, dedifferentiated and
mesenchymal chondrosarcoma
Osteogenic (19%)
Osteoid osteoma, osteoblastoma
Osteosarcoma
Unknown (10%)
Giant cell tumor
Ewing sarcoma, giant cell tumor,
adamantinoma
Histiocytic
Fibrous histiocytoma
Malignant fibrous histiocytoma
Fibrogenic
Fibroma
Desomplastic fibroma, fibrosarcoma
Notochordal
Chordoma
Vascular
Hemangioma
Hemangioendothelioma,
hemangiopericytoma, angiosarcoma
Lipogenic
Lipoma
Liposarcoma
Neurogenic
Neurilemmoma (schwannoma)
Osteoid osteoma
- Benign bone tumor seen often in teens and young adults
- < 2 cm diameter and have predilection for cortex of long bones
- Painful lesions and can mimic osteomyelitis (PGE2)
- Well circumscribed mass of woven bone rimmed by osteoblasts
- This is called the nidus and is surrounded by reactive bone
Osteosarcoma
- Malignant mesenchymal tumor in which cancerous cells produce bone
matrix
- Most common non-hematopoietic bone tumor
- 75% occur before the age of 20 years. Second peak in elderly
- Commoner in males (1.6:1)
- Arises from metaphysis of long bones. 60% arise around the knee
- Patients with hereditary retinoblastomas have a 1000 fold risk
- Metastasizes through hematogenous route (90% to lungs)
- Advances in treatment (chemotherapy and limb salvage therapy) has
improved long term survival to 60-70%
Osteogenic Sarcoma
10 20 30 40 50 60 70 yrs
Osteosarcoma - subcategorization
Based on
Subtypes
Location
Intramedullary / intracortical / periosteal etc
Differentiation
Well / poorly
Histology
Osteoblastic / chondroblastic / fibroblastic,
telangiectatic / giant cell / small cell
Others
Solitary / multicentric
Primary / secondary
Osteosarcoma
Gross: Bulky, gritty, hemorrhage and necrosis,bone destructive and
spreading in different directions
Microscopy:
- Bizarre tumors cells with pleomorphic nuclei
- Multinucleated giant cells
- Formation of “lacy osteoid”
- Formation of other types of matrix
- Conspicuous vascular invasion - metastasize to lungs, brain
X-ray:
- Large destructive lytic and osteoblastic mass with infiltrating margins
- Lifts periosteum (Codman triangle) and produces reactive periosteal
bone formation
Tumor grading
- Low grade
- High grade
- Cell pleomorphism
- Tumor
differentiation
- Necrosis
- Mitotic activity
Hematogenous spread is very common and 10-20% have
pulmonary metastases at the time of diagnosis
Bone tumors
Histologic type
Benign
Hematopoietic (40%)
Malignant
Myeloma, lymphoma
Chondrogenic (22%)
Osteochondroma, chondroma,
chondroblastoma, chondromyxoid fibroma
Chondroscarcoma, dedifferentiated and
mesenchymal chondrosarcoma
Osteogenic (19%)
Osteoid osteoma, osteoblastoma
Osteosarcoma
Unknown (10%)
Giant cell tumor
Ewing sarcoma, giant cell tumor,
adamantinoma
Histiocytic
Fibrous histiocytoma
Malignant fibrous histiocytoma
Fibrogenic
Fibroma
Desomplastic fibroma, fibrosarcoma
Notochordal
Chordoma
Vascular
Hemangioma
Hemangioendothelioma,
hemangiopericytoma, angiosarcoma
Lipogenic
Lipoma
Liposarcoma
Neurogenic
Neurilemmoma (schwannoma)
Benign cartilage tumors:
Osteochondroma: Bony spur / exostosis. Mushroom shaped bone projection covered
by cartilage cap
Chondroma:
- Enchondroma ( intramedullary) or juxtacortical
- Usually solitary and metaphyseal in short tubular bones and < 3 cms dia
- Multiple tumors form part of Olliers disease (enchondromatosis)
- Develop from rests of growth plate cartilage
- Contain well circumscribed nodules of cartilage and cytologically benign
chondrocytes
- Endochondral ossification is seen at periphery
- X-ray shows typical “O ring” sign
- Malignant transformation more common in Ollier disease
Chondrosarcoma
- Malignant tumors that form neoplastic cartilage
- Subtypes:
a) Intramedullary and juxtacortical
b) Conventional (hyaline / myxoid), clear cell, dedifferentiated,
mesenchymal
c) Low grade to high grade
- Usually seen in patients above 40, more in men (2:1)
- More often in central parts of skeleton
- Large bulky tumors with glistening cut surface with central
necrosis
- Tumor spreads by pushing margins
- Low grade tumors almost similar to enchondromas
- High grade show marked pleomorphism and bizarre morphology
Bone tumors
Histologic type
Benign
Hematopoietic (40%)
Malignant
Myeloma, lymphoma
Chondrogenic (22%)
Osteochondroma, chondroma,
chondroblastoma, chondromyxoid fibroma
Chondroscarcoma, dedifferentiated and
mesenchymal chondrosarcoma
Osteogenic (19%)
Osteoid osteoma, osteoblastoma
Osteosarcoma
Unknown (10%)
Giant cell tumor
Ewing sarcoma, giant cell tumor,
adamantinoma
Histiocytic
Fibrous histiocytoma
Malignant fibrous histiocytoma
Fibrogenic
Fibroma
Desomplastic fibroma, fibrosarcoma
Notochordal
Chordoma
Vascular
Hemangioma
Hemangioendothelioma,
hemangiopericytoma, angiosarcoma
Lipogenic
Lipoma
Liposarcoma
Neurogenic
Neurilemmoma (schwannoma)
Ewing Sarcoma and PNET (primitive neuro-ectodermal
tumor)
- Primary malignant small round cell tumors of bone and soft tissue
- Share similar neural phenotype and chromosomal translocation
- Second commonest malignant non-hematopoietic bone tumor in
children
- Children 10-15 years old, boys more affected. Diaphysis of long
bones
- 85% show t(11;22)
- Tumors arise from medullary cavity, invade cortex, spread to soft
tissue
- Comprised of small round cells slightly larger than lymphocytes
- Cells are rich in glycogen.
- May show Homer-Wright rosettes. Necrosis is seen
- Xray shows typical layers of reactive bone (“Onion-skin” pattern
Gross:
- Arise in medullary cavity
(diaphysis)
- Invade cortex and periosteum
- Tan white colour with
hemorrhage and necrosis
Microscopy:
- Sheets of uniform small
cells
- Rosettes (Homer-Wright)
- Few mitotic figures
Giant Cell Tumor:
(Osteoclastoma)
- Contains numerous osteoclast type of giant cells (monocyte
macrophage)
- Benign but locally aggressive
- Patients between 20 to 40 years
- Involve both epiphysis and metaphysis and are common in long
bones
- Xray shows typical soap bubble appearance and thin reactive shell
- Tumor comprised of oval mononuclear cells growing in sheets mixed
with osteoclast type of giant cells with more than 100 nuclei
- Necrosis and hemorrhage common
- Biologically unpredictable tumors
Involve both epiphysis and
metaphysis
Large purely lytic - “Soap bubble”
tumors
Gross:
- Large, red-brown
- Hemorrhage and cystic
degeneration
- Uniform mononuclear cells
in sheets with increased
mitoses
- Numerous osteoclast type
of giant cells with > 100
nuclei