Kamis, 03 Juli 2008
Non-odontogenic tumour of the jaws

Non-odontogenic tumour of the jaws

Juni Handajani

Department of Oral Biology

Faculty of Dentistry

Gadjah Mada University

OSTEOMA AND OTHER BONY OVERGROWTH


  • True tumours consisting of bone (either compact or cancellous) are occasionally seen
  • Localised overgrowth of bone (exostoses) are more common
  • Consist of lamellae of compact bone but large specimen may have core of cancellous bone
  • Small exostoses may form irregularly on the surface of alveolar processes
  • Specific variants are torus palatinus and torus mandibularis
  • Differ from other exostoses only in that they develop in characteristic sites and are symmetrical

Torus palatinus


  • Commonly forms towards the posterior of the midline of the hard palate
  • The swelling is rounded and symetrical
  • Sometime with a midline groove
  • It is not usually noticed until age and
  • If it interferes with the fitting a denture, should be remove

Tori mandibularis


  • Form on the lingual aspect of the mandible opposite the mental foramen
  • Typically bilateral
  • Forming hard
  • Rounded swelling

Compact and cancellous osteoma

  • Consist of lamellae of bone
  • Sometimes in layers like an onion but in haversian systems
  • The dense bone contains occasional vascular spaces and grows very slowly
  • Cancellous osteomas consist of slender trabeculae of bone with interstitial marrow spaces and a lamellated cortex

Gardner’s syndrome

  • Comprises multiple osteomas of the jaw
  • Polyposis coli with a high malignant potential
  • Often other abnormalities: dental defect and epidermal cysts or fibromas
  • It is inherited as autosomal dominant trait
  • Penetrance is weak

OSTEOCHONDROMA (Cartilage-capped osteoma)

  • Grow by ossification beneath a cartilaginous cap (not be visible in rö)
  • Most arise from the region of coronoid or condylar process
  • Form a hard bony protuberance which can interfere with joint function
  • Almost any age can be affected
  • Pathology
  • The lesion is subperiosteal
  • Has a cap of hyaline cartilage, where the cartilage cells are sometimes regularly aligned or irregular and contain minute foci of ossification
  • As age advances, the mass progressively ossifies
  • Benign and usually cease to grow after skeletal maturation

MALIGNANT NEOPLASMS OF BONE

  • Highly malignant
  • The most common primary (non-odontogenic) neoplasm of bone
  • Rare especially in jaws
  • Typically seen between the aged 30 and 40
  • Males are slightly more frequently
  • The body of mandible is common site
  • Typically a firm swelling which grows noticeably in a few months
  • Become painful
  • Teeth may be loosened
  • Paraesthesia or loss of sensation in the mental nerve area
  • Metastases to the lung may develop early

Radiographically

  • Appearance are variable
  • Irregular bone destruction usually predominates over bone formation
  • Bone formation in a soft tissue mass is highly characteristic, but rarely seen

Pathology

  • Neoplastic osteoblasts vary in size and shape, may be small and angular or large and hyperchromatic
  • Mitoses may be seen, particularly in the more highly cellular areas
  • Giant cells may be conspicuous, but many cell are nondescript
  • Bone formation does not necessarily predominate
  • Osteoid formation is the main diagnostic criterion and is seen in metastases
  • Cartilage and fibrous tissue are usually present and sometime predominate but usually in part of tumour

Chondroma and chondrosarcoma

Histologically

  • Consist of hyaline cartilage
  • The cells are irregular in size and distribution
  • Calcification or ossification may develop
  • 20% chondrosarcomas in maxillofacial area were originally thought to have been chondromas

Chondrosarcoma

  • Affect adults at an average age of about 45.
  • The anterior maxilla is the site in 60% of cases.
  • Pain, swelling or loosening of teeth
  • Radiolucent area are typical
  • The radiolucency can be well or poorly circumscribed or may appear multilocular
  • Calcification present and may be widespread and dense

Pathology

  • The cartilage is compartively well-formed or, less often, poorly differentiated or mixoid.
  • The chondrocytes are pleomorphic, often binucleate and may show mitotic activity
  • Maxillofacial chondrosarcomas are aggressive
  • Local recurrence or persistent tumour is the main cause of death
  • Lungs or other bones are the usual sites of distant spread but fewer than 10% of these tumours metastasise

Mesenchymal chondrosarcoma

  • Is uncommon but highly malignant variant
  • Is highly cellular tumour in which there are only small foci of tissue recognisable as poorly-formed cartilage
  • It is some times very vascular

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