Osteosarcoma 6d1k14

OSTEOSARCOMA (OSTEOGENIC SARCOMA)

• Introduction • Definition • Clinical features • Radiographic features • Histological variants • Treatment and prognosis

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DEFINITION • Osteosarcoma is an aggressive malignant neoplasm arising from primitive transformed cells of mesenchymal origin (and thus a sarcoma) that exhibit osteoblastic differentiation and produce malignant osteoid. • It is the most common histological form of primary bone cancer in age 12-25yrs. • That have the ability to produce osteoid or immature bone, with an incidence of 0.7 per million.

OSTEOSARCOMA (OSTEOGENIC SARCOMA) • It is the most common primary neoplasm of bone, but overall is rare, especially in the jaws. Etiology • The exact etiologic factors for the development of osteosarcoma are unknown. • Osteosarcomas are associated with mutations in the retinoblastoma gene (RB) and p53 • Irradiation, trauma or pre-existing bone disorder such as Paget`s disease or fibrous dysplasia might be predisposing factors

CLASSIFICATION 1. According to clinical appearance: • Conventional (endosteal) osteosarcoma – the tumor arises from the osteoblasts in the endosteum and grows within the marrow spaces. – It penetrates or partially destroys the overlying cortex to extend beneath the periosteum. • Parosteal osteosarcoma – this uncommon variant of osteosarcoma has somewhat better prognosis. – The tumor grows from the external surface of the bone. – These tumors tend to grow slowly and metastasize late.

CONVENTIONAL OSTEOSARCOMA

2. According to radiographic picture: – Osteoblastic (sclerosing) type – Osteolytic type 3. According to histolo gic features: – Osteoblastic osteosarcoma. – Fibroblastic osteosarcoma. – Chondroblastic osteosarcoma. – Telangiectatic osteosarcoma.

CLINICAL FEATURES • Age: young age. • Sex: males more than females. • Site: This lesion mainly affects the long bones and is rare intraorally. • Orally the mandible is more affected than the maxilla. Features • Pain and swelling of the affected bone. • History of trauma. • Osteosarcoma of the jaw is a rapidly invasive lesion, there

RADIOGRAPHIC FEATURES • The radiographic features of osteosarcoma are variable depending on the degree of bone formation in the tumor. • In the osteoblastic or sclerosing type irregular foci of radiopacity intermingled with areas of radiolucency is noted. • In the osteolytic type irregular radiolucent area with no radiopacities can be seen.

RADIOGRAPHIC FEATURES • In rapidly growing tumors when the periosteum is raised, specules of new bone are laid down perpendicular to the cortex giving the “sun ray appearance” • At the junction between raised and normal periosteum a wedge of reactive bone referred to as “Codman`s triangle” may develop.

PERIAPICAL RADIOGRAPH Symmetrical widening of the periodontal ligament space of one or more teeth is considered an early and diagnostic feature of osteosarcoma

WIDENING OF PERIODONTAL LIGAMENT SPACE IS AN EARLY SIGN OF OSTEOSARCOMA

HISTOPATHOLOGY • Osteosarcomas originate from bone cells (osteoblasts) that are variable in appearance and have wide potentialities. • The microscopic appearance of the tumor is therefore widely variable, even within an individual lesion. The lesion consists of: • Collections of atypical neoplastic osteoblasts showing considerable variation in size and shape, they may be small and angular or large and hyperchromatic. • Mitoses may be prominent, particularly in the most cellular areas of the tumor.

• The formation of tumor osteoid or bone is a diagnostic histologic criterion of the lesion. • The neoplastic cells do not rim the tumor bone in the manner seen in normal or reactive bone. • The trabeculae of tumor bone tend to be delicate and irregularly arranged.

HISTOPATHOLOGY • Osteoblastic osteosarcoma is a variant of osteosarcoma showing extensive formation of tumor osteoid and bone. • Fibroblastic osteosarcoma shows the tendency of the tumor cells to form varying amounts of collagen. • Tumour osteoid and bone are sparse or absent. • Chondroblastic osteosarcoma is an aggressive variant of osteosarcoma in which the tumor cells form malignant chondroid tissue. • Telangiectatic osteosarcoma is a tumor characterized by the presence of large blood filled cystic spaces.

TREATMENT & PROGNOSIS

TREATMENT MEASURES FOR OSTEOSARCOMA OF JAW BONES INCLUDE THE FOLLOWING:

- Any combination of chemotherapy, radiation therapy, and invasive procedures, maybe used to treat the tumor . - Wide surgical excision of Jaw Osteosarcoma and removal of the entire lesion is the standard treatment mode. If the tumor is not fully removed, then it will recur .

*After surgical removal of the tumor, reconstructive surgical procedures may be planned to correct facial defects and restore the face * Embolization of the tumor is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure * Post-operative care is important: A minimum activity level is to be ensured, until the surgical wound heals

REFERENCE 1. Oral & Maxillofacial Pathology - Saunders 2 edition 2. Cawson’s essentials of oral pathology and oral medicine 3. Regezi oral pathology- 5th edition 4. PubMed

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