Pathology for year 2, unit 3 Lecture number 14 & 15. NB: The total number of lectures is 17.

Neoplastic changes of bones أ. م. د. محمد شنين علي العبادي M. B. Ch. B. & F. I. C. P.(Hematopathology) الاثنين 2015/4/6 الساعة الثامنة صباحا - التاسعة والثلاثاء 2015/4/7 الساعة التاسعة صباحا - العاشرة

Bone tumors 1.Primary tumors, arising from the bone. 2.Secondary (metastatic) tumors, arising from other organs (not from the bones) and reach the bone by metastasis. NB: The secondary tumors are more common than the primary bone tumors. Neoplastic changes of bones

Primary bone tumors *Have great morphological diversity. (diversity=differences). 1.Benign primary bone tumors. 2.Malignant primary bone tumors. NB: Benign primary bone tumors are much more common than malignant types. Neoplastic changes of bones

Common features for all primary bone tumors 1.Each tumor affects certain bone/bones e.g osteoma (benign) affects facial bones or skull while osteosarcoma (malignant) affects areas around the knee joint (distal femur or proximal tibia). 2.Each tumor affects certain age groups e.g osteoma affects ages between yr. while osteosarcoma affects ages between yr. Neoplastic changes of bones

Common features for all primary bone tumors 3. Each tumor has certain morphological features. e.g osteoma (benign) is a growth attached to the bone and morphologically resembling normal bone while osteosarcoma is an outside growth (lifting the periosteum) and inside growth (to medullary cavity) and forming osteoid (bone forming tumor).

Neoplastic changes of bones Q. What are the benign primary bone tumors? Answer: 1.Osteoma 2.Osteoid osteoma. 3.Osteoblastoma. 4.Chondroma. 5.Oseochondroma.

Neoplastic changes of bones Q. What are the differences among the 5 types of benign primary bone tumors? Answer: 1.They affect certain bones. 2.They affect certain age groups. 3.They have certain morphological features.

Neoplastic changes of bones Q. What are the malignant primary bone tumors? Answer: 1.Osteosarcoma. 2.Chondrosarcoma. 3.Ewing sarcoma. Similarly, they are affecting different age groups, different anatomical areas and have different morphological features. Unfortunately, they have hematogenous spread e.g at time of diagnosis of oseosarcoma 15% of patients have lung secondaries (lung metastasis).

Neoplastic changes of bones Q. Is there another classification for bone tumors? Answer: Yes, there is another classification which classified bone tumors into Bone forming tumors (like osteoma, osteosarcoma, & others) and Cartilage forming tumors (like chondroma, chondrosarcoma, & others).

Osteosarcoma Osteosarcoma is a bone producing malignant tumor of bones. Osteosarcoma can be primary or secondary (metastatic). The primary one affects age groups between yr. while the secondary one affects ages more than 40 yr. with similar histological features. Osteosarcoma is the commonest primary malignant bone tumor, next one is chondrosarcoma followed by Ewing sarcoma.

Osteosarcoma Aetiology 1. Unknown in youngs 2. May follow bone irradiation, paget disease or bone infarcts in elderly. Anatomical sites of affection: Around the knee joint (distal femur or proximal tibia). Other sites have less chance of involvement like areas around the hip joint, around the shoulder joint, and jaw.

Osteosarcoma Ages of involvement years in 75% of cases; however, there is another peak in old age groups.

Osteosarcoma Pathogenesis Osteosarcoma is closely associated with RB (Retinoblastoma) gene mutation. Persons with hereditary retinoblastoma have 1000X greater risk of developing or acquiring osteosarcoma. Next most important mutation is P 53 gene mutation and other genes. Such tumors arise in areas of greatest bone growth.

Morphological features 1.Gross features Osteosarcomas are gritty (stony), gray-white, destroying the surrounding tissues. 2. Microscopical features Malignant cells have Pleomorphism, hyperchromatism, mitotic figures and most imprtant feature for diagnosis is new bone formation (osteoid formation) with vascular invasion. Osteosarcoma

Codman triangle X-ray

Codman triangle X-ray

Codman triangle X-ray

Osteosarcoma X-ray

Osteosarcoma Proximal tibia

Osteosarcoma Thigh swelling

Osteosarcoma Eosinophilic osteoid +pleomorphic osteoblasts

Osteosarcoma Eosinophilic osteoid +pleomorphic osteoblasts

Osteosarcoma

Retinoblastoma

Please answer by T or F 1.Osteoma is morpholgically similar to chondroma. 2.Osteosarcoma is never secondary. 3.Osteoid osteoma is an aggressive bone tumor 4.Ewing sarcoma is characterized by early spread (metastasis) through blood. 5.Osteosarcoma is typically affecting old ages 6.Osteosarcoma can affect old groups

Please answer by T or F 7. Bone formation by malignant cells is histopathologically not essential for the diagnosis of ostema or osteosarcoma. 8. Chondroma and chondrosarcoma are grossly gritty (stony). 9. Chondrosarcoma is the commonest primary malignancy of bones. 10. Osteoblastoma is a benign bone tumor.

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