Swelling-can either be neoplasmata or harmatoma or the result of infections.

Tumour – neoplasmata (new growth)

The term tumours should be better used in the concept of a neoplasm (new growth which may be formation or new growth).

Neoplasm: it implies that there is an abnormal type of growth which may be evident not only in the intact animal but also when the cells are grown in culture.

No tendency of invading surrounding tissues.

Excessive accumulation of cells produces an expanding mass which may cause pressure atrophy while others form fibrous capsule.

Tumours become well circumscribed and not intimately connected with surrounding tissue except for those points of entry of vascular supply.

These facilitates easy surgical excision, do not recur following complete local excision.

Due to encapsulation, usually round but shape depends on the surrounding structures. Ulceration and haemorrhage are rare.

Microscopically-well differentiated, cells are regular in size,staining and shape. Scanty mitotic figures and if present are of normal type.

Cells can infiltrate and erode surrounding tissues.

Normal cells are enveloped and destroyed and the tumour edge (therefore) becomes ill defined.

Complete surgical removal is difficult, malignant cells often remain behind to cause local recurrence.

Spread by following areas/planes of least resistance e.g. canals.

They lack capsules because tumour cells actively infiltrate the adjacent tissues. Sometimes a false capsule may be formed due to an expansive growth.

Have irregular outlines with diffusely defined borders.

Usually large in size than benign.

Ulceration and haemorrhage are common.

Carcinoma: refers to a malignant tumour of the epithelial cells.

Sarcoma: refers to a malignant tumour of connective tissues

An ulcer failing to heal within/after a few weeks(10 days) of treatment should be regarded as malignant until proved otherwise.

Tumours are undifferentiated or poorly differentiated, when differentiation is not so well developed and recognition of the tissue of origin is often difficult or impossible.

Poorly differentiated neoplastic cells are making an attempt to resemble the structure of those found normally in the tissue

High mitotic figures/activity.

Anaplastic tumours: derived from epithelial or mesenchymal tissue is referred to as anaplastic carcinoma or anaplastic sarcoma respectively.

Tumours derived from primordial tooth forming tissues.

Example

Ameloblastoma

Adenomatoid odontogenic tumour

Calcifying epthelial odontogenic tumour

Keratocystic odontogenic tumour

Ameloblastic fibroma

Odontomas

Odontogenic myxoma

cementoblastoma

A true neoplasm of enamel organ tissue.

most common epithelial odontogenic tumour.

Accounts for approximately 1% of all oral tumours and cysts in the mandible and maxilla.

Age incidence is 20-50 yrs with a peak age in 3rd and 4th decades but ages vary from young to olds.

Men and women are equally affected.

It derives from epithelial rests closely associated with development of teeth.

It can also derive from epithelium or epithelial lining of odontogenic cysts.

Epithelial rests include: cell rests of Malassez, remnants of dental lamina or enamel organ, the basal layer of oral epithelium.

80% of lesion occurs in the mandible involving mostly the molar, angle and ramus region.

Molar and canine regions are involved in the maxilla.

Grows slowly, asymptomatic in early stages and discovered during routine x-ray examination.

When in the maxilla it may become quite large before it is discovered-nasal obstruction may be the first symptom. This is because of the presence of maxillary sinus (tumour has to fill the sinus)

On examination

it appears as a gradually growing round swelling of the buccal cortical plate but ameloblastoma can cause expansion of lingual cortical plate (unlike cysts).

Bony hard, normal overlying mucosa in early stages.

Tumour continues to enlarge, bone gets thinner and thinner leading to ping pong rebounding and then more thinning will lead to egg shell cracking effect.

Overlying mucosa still normal but later bone is perforated and tumour may protrude into the oral cavity and the overlying mucosa may ulcerate (ulceration is not common).

Progressive loosening and sometimes displacement of teeth.

Due to mandibular canal involvement, hypoesthesia of the lower lip may be present (occasionally).

Closely trabeculated zones of osseous destruction gives an appearance of a multilocular cystic cavity.

In most cases, radiographic pictures shows the unilocular aspect common in cysts.

Bones often appears to be replaced by a number of well defined radiolucent areas that give the lesion a honey combed or a soap bubble configuration

Displacement of teeth to the periphery of the tumour and resorption of roots are more frequently in ameloblastomas than in cysts.

Follicular

Plexiform

Desmoplastic

Acanthomatus

Granular cell

Basal cell

The tumour is not radiosensitive, so surgery is the treatment of choice.

Tumour enucleation especially in unicystic ameloblastoma.

Complete resection of the affected area of the bone including a margin of about 1-1.5cm outside the appearance of periphery of the tumour.

Recurrences occur following incomplete surgical removal.

Follow the patient for up to 5 years.

An uncommon histologic type of odontogenic tumour.

Characterized by formation of duct-like structures by the epithelial component.

It has uncertain histogenesis hence the tumour is not known if it is a true neoplasm or not.

Age-affects younger patients during their 2nd decade of life (age range between 5 and 53 years with mean age 18years).

Sex –females are more affected than males at ratio of 2:1

Site –common location in the anterior maxilla.

Frequently occurs in the anterior part of the jaws, anterior to the cuspids in both jaws and rarely distal to the premolar.

Grows between 1.5-3cm but may reach 7cm.

An asymptomatic swelling.

The cyst formation may be related to late disturbance in odontogenesis

A destructive lesion well or not well circumscribed.

Resembles a dentigerous cyst but it extends further than the cementoenamel junction.

Unilocular radiolucence with occasional foci of dense radiopacity.

Root resorption rare but separation of roots or displacement of adjacent teeth is noted.

Conservative surgical excision

Recurence is rare following complete sucessful excison

Tumour formed by overgrowth of complete dental tissues.

They are known as mixed odontogenic tumour because they are composed of both epithelal and mesenchymal components.

Both epithelial and mesenchymal tissues and their respective cells appear normal in morphology but have deficit in structural arrangement thus odontomas can be hamartomatous lesion or malformation rather than a true neoplasma

Compound odontoma

Composed of small tooth like structures and they are commonly located in the anterior maxilla

Complex odontomas

Found in the posterior mandible, consist of irregular mass of dental tissue that do not resemble normal tooth

Asymptomatic in nature,discovered on circumstances such as routine radiogaph, delayed tooth eruption

Delayed eruption or non erupting tooth, impaction of tooth

Swelling in some cases may be noticed, the swelling are slow growing in nature can cause facial asymmetry

Pain incase of secondary infection

common in children, adolescents and young adults

Compound odontomas appear as a collection of tooth like structures surrounded by radiololucent zone.

Adjacent tooth may be displaced but no resorption seen.

Complex odontomas appear as spherical or ovoid radioopacity with fine radiating periphery sorrounded by radioluscent zone.

Conservative surgical excision.

Prognosis is good, little to no chances of recurrence