Classic look of an<unk>  of the right mandible in the place of a former wisdom tooth. Well defined, unilocular, radiolucent lesion within the bone. Diagnosis is usually radiological. However, definitive diagnosis is through biopsy. Aspirational biopsy of<unk> s contains a greasy fluid which is pale in colour and contains keratotic squames. Protein content of cyst fluid below 4g% is diagnostic of<unk> s. Smaller and unilocular lesions resembling other types of cysts may require a biopsy to confirm the diagnosis. On a CT scan, the radiodensity of a<unk> ic<unk>  tumour is about 30 Hounsfield units, which is about the same as ameloblastomas. However, ameloblastomas show more bone expansion and seldom show high density areas. Radiographs of<unk> s show well-defined radiolucent areas with rounded or scalloped margins which are well demarcated. These areas can be multilocular or unilocular. The growth pattern of the lesion is very characteristic from which a diagnosis can be made as there is growth and spread both forward and backward along the medullary cavity with little expansion. No resorption of teeth or inferior dental canal and minimal displacement of teeth is seen. Due to lack of expansion of the<unk> , the lesion can be very large when radiographically discovered. Differential diagnosis Radiologically<unk>  myxoma *Ameloblastoma *Central giant-cell granuloma *Adenomatoid<unk>  tumor *Dentigerous cyst (follicular cyst) Histologically *Orthokeratocyst *Radicular cyst (particularly if the<unk>  is very inflamed) *Ameloblastoma Histology<unk> s have a diagnostic histological appearance. Under the microscope,<unk> s vaguely resemble keratinized squamous epithelium; however, they lack rete ridges and often have an artifactual separation from their basement membrane. The fibrous wall of the cyst is usually thin and uninflamed. The epithelial lining is thin with even thickness and parakeratinised with columnar cells in the basal layer which have focal reverse polarisation (nuclei are on the opposite pole of the cell). The basal cells are an indication of the<unk>  origin as they resemble pre-ameloblasts. The epithelium can separate from the wall, resulting in islands of epithelium. These can go on to form 'satellite' or 'daughter' cysts, leading to an overall multilocular cyst. Presence of daughter cysts is particularly seen in those with NBCCS. Inflamed cysts show hyperplastic epithelium which is no longer characteristic of<unk> s and can have resemblance to radicular cysts instead. Due to areas of focal inflammation, a larger biopsy is required for correct diagnosis of<unk> s. File:Keratocystic<unk>  tumour - 2 - intermed mag.Intermediate magnification of an<unk>  showing a folded cyst. File:Keratocystic<unk>  tumour - intermed mag.Intermediate magnification of an<unk>  File:Keratocystic<unk>  tumour - 2 - high mag.High magnification of an<unk> .
Odontogenic keratocyst
Dentigerous cyst
Glandular odontogenic cyst
Cholesteatoma
Pseudolymphoma
Aquarium granuloma
Enamel pearl
Idiopathic facial aseptic granuloma