Bone Tumors PDF

Bone tumors  They are either primary or secondary Classification of primary bone tumors;- According to behavior, they are either benign or malignant According to histogenesis are classified as follows;- 1. Hematopoietic;- multiple myeloma & malignant lymphoma. 2. Chondrogenic;- benign– ost...

Bone tumors  They are either primary or secondary Classification of primary bone tumors;- According to behavior, they are either benign or malignant According to histogenesis are classified as follows;- 1. Hematopoietic;- multiple myeloma & malignant lymphoma. 2. Chondrogenic;- benign– osteochondroma - chondroma - chondroblastoma Malignant – primary chondrosarcoma -- secondary chondrosarcoma 3. Osteogenic Malignant – osteosarcoma Benign- steoma - steoid steoma - osteoblastoma 4. Unknown origin Benign – Gaint cell tumor Malignant – Ewing's sarcoma 5. Histocytic origin Benign Fibrous histocytoma Malignant histocytoma 6. Fibrogenic Benign- Metaphyseal fibroma Malignant -Desmoplastic fibroma - fibrosarcoma 7. Notochordal benign Malignant -chondroma 8. Vascular Benign- hemangioma Malignant -Hemangiopericytoma 9. Lipogenic Benign - lipoma Malignant – liposarcoma 10. Neurogenic Malignant –neurilemmoma  Classification of Primary Tumors Involving Bones Histologic Type Benign Malignant Hema topoiet ic (40%) ---------------- 1-Myeloma 2-Ma ligna nt ly mphoma Chondrogenic (22%) 1-Ost eochondroma 1-Chondrosa rcoma 2-Chondroma 2-Dedifferent ia t ed chondrosa rcoma 3-Chondrobla stoma 3-Mesenchy ma l chondrosa rcoma 4-Chondromy xoid fibroma ----------------------------------- Ost eogenic (19%) 1-Ost eoid ost eoma 1-Ost eosa rcoma 2-Ost eobla stoma -------------------------------------------------- Unknow n origin (10%) G ia nt cell t umor Ew ing”s sa rcoma G ia nt cell t umor Ada ma nt inoma Hist iocy t ic origin Fibrous hist iocy toma Ma ligna nt fibrous hist iocy toma Fibrogenic Met a phy sea l fibrous defect (fibroma ) Desmopla st ic fibroma Fibrosa rcoma Notochorda l ------------------------- 1-Chordoma Va scula r 1-Hema ngioma 1-Hema ngioendot helioma 2-Hema ngiopericy toma L ipogenic 1-L ipoma 1-L iposa rcoma Neurogenic 1-Neurilemmoma -------------------------------- General characteristic 1. Affect males more than females except giant cell tumor 2. Benign tumors are 100 folds their counterpart malignant 3. They are common tumors in children. Majority tend to occur in ages below 25 years. However chondrosarcoma affect age group 30-60 years and giant cell tumor affect age group 20-40 years 4. The most frequent location is around the knee (lower femur and upper tibia). However osteoblastoma frequently affect the vertebrae, chondroma affects the bones of hands and feet, osteoma affect the facial bones and skull , chondrosarcoma affect the bones of the shoulder ,pelvis, ribs and proximal femur. 5. X-Ray findings is crucial for diagnosis. The characteristic findings include : I. God man’s triangle in osteosarcoma II. “soap bubble” appearance in giant cell tumor. 6. Current evidence strongly suggest that genetic alteration underlie their development E.g. mutation affecting specific suppressor genes. 7.Bone infarcts , chronic osteomyelitis , piget’s disease, radiation, metal prosthesis are associated with increased incidence of bone neoplasia. 8.Benign tumors frequently are asymptomatic , while malignant ones present with slow growing mass, sudden pathological fractures and sometimes pain. Benign bone tumors

A. Osteochondroma (exostosis) is the most common benign tumor of bone. (1) This bone growth is covered by a cap of cartilage projecting from the surface of a bone. (2) It occurs most frequently in men younger than 25 years of age. (3) It may be a hamartoma rather than a true neoplasm. (4) The tumor most often originates from the metaphysis of long bones, with the lower end of the femur or the upper end of the tibia being favored locations. (5) It rarely undergoes transition to chondrosarcoma; malignant transformation is more frequent in multiple familial osteochondromatosis, a rare hereditary variant characterized by multiple lesions. Osteochondroma cartilagenous cap bony stalk b. Giant cell tumor

(1) This tumor is characterized by monotonous oval- or spindle- shaped cells intermingled with numerous multinucleate giant cells. (2) The peak incidence is in persons between 20 and 40 years of age. It is somewhat more common in women than in men. (3) The tumor occurs most often on the epiphyseal end of long bones; more than 50% occur around the knee. (4) Although this tumor is benign, it is locally aggressive and often recurs after local curettage. (5) It may be associated with secondary formation of an aneurysmal bone cyst (ABC), a benign process that can occur in isolation or in association with other tumors. ABCs classically show a “soap bubble” appearance on radiography. GCT – macroscopic pathology Well circumscribed tumor in epiphysis and metaphysis Lytic defect with cortical expansion Residual bone trabeculae = soap bubble appearance GCT - histopathology Malignant bone tumors

A. Osteosarcoma (1) This is the most common primary malignant tumor of bone. (2) The peak incidence is in males 10 to 20 years of age. (3) The tumor occurs most frequently in the metaphysis of long bones; the proximal portion of the tibia and most distal portion of the femur (around the knee) are preferred sites.  (4) There are several histologic variants: osteoblastic tumors show prominent osteoid formation, whereas chondroblastic tumors form cartilaginous matrix and may have relatively scant bony differentiation. Malignant cartilage-forming bone tumors in children invariably represent chondroblastic osteosarcomas, rather than conventional chondrosarcomas, because the latter is virtually never seen in pediatric patients. The fibroblastic variant may easily be mistaken for a reactive process (and vice versa). Osteosarcoma - macroscopic Ill-defined destructive tumour in metaphysis Elevation of periosteum – Codman’s triangle Clinical characteristics

(a) Pain and swelling and occasionally pathologic fracture (b) A two- to three-fold increase of serum alkaline phosphatase (c) Lifting of the periosteum by the expanding tumor, which creates a characteristic radiologic appearance known as the Codman triangle. Another radiologic sign is a spiculated “sunburst” pattern of growth. (d) Early hematogenous spread to the lungs, liver, and brain Predisposing factors
(a) Paget disease of bone, fibrous dysplasia, chondroma, osteochondroma (b) Ionizing radiation (c) Bone infarcts (d) Familial retinoblastoma (in these patients, surgical cure of the primary ocular tumor is often followed by the later development of osteosarcoma, presumably due to loss of the Rb suppressor gene locus on chromosome 13) B. Chondrosarcoma

(1) This is a malignant cartilaginous tumor. (2) The peak incidence is in men 30 to 60 years of age. In its conventional form, it is virtually unheard of in children. (3) The neoplasm may arise as a primary tumor or from transformation of preexisting cartilaginous tumors, especially multiple familial osteochondromatosis or multiple enchondromatosis. (4) Characteristic sites of origin include the pelvis, spine, or scapula; the proximal humerus or proximal femur; and femur or tibia near the knee. Chondrosarcoma * Dense calcifications in cartilaginous Lobular cartilagenous tumour with matrix. Locally destructive growth with spread to soft tissue. soft tissue extension.* C. Ewing sarcoma

(1) This extremely anaplastic “small blue cell” malignant tumor has a morphologic resemblance to malignant lymphoma. (2) It is virtually indistinguishable from primitive neuroectodermal tumor (PNET) of the soft tissue.  Both tumors most often demonstrate the 11;22 chromosomal translocation, which results in the fusion of the EWS1 gene to the FLI-1 gene. Variant translocations—most often t(21;22)—are occasionally encountered. (3) It occurs most often in long bones, ribs, pelvis, and scapula. (4) It has a peak incidence in boys younger than 15 years of age. (5) It follows an extremely malignant course with early metastases. (6) It responds to chemotherapy. (7) In early stages, Ewing sarcoma may clinically mimic acute osteomyelitis. Ewing’s sarcoma / PNET intramedullary, diaphyseal - femur, tibia, humerus, pelvis, ribs ill-defined, permeative pattern of bone destruction periosteal reaction (onion skin) early extension to soft tissue Note overlap with osteomyelitis! Ewing’s sarcoma / PNET CD99