Some observations on the fluids of odontogenic cysts

Differentiation of cystic lesions in the jaw by conventional magnetic resonance imaging and diffusion-weighted imaging

OBJECTIVES

This study aimed to determine the discrimination power of apparent diffusion coefficient (ADC) for cystic lesions in the jaw using MRI.

METHODS

We selected 127 cystic lesions, comprising dentigerous cysts (DCs), odontogenic keratocysts (OKCs), and unicystic ameloblastomas (UABs), from our MRI database examined by 3T MRI, including diffusion-weighted imaging sequences, and we reviewed their imaging characteristics. We attempted to discriminate the three types of lesions by ADC values with receiver operator characteristic analysis; however, satisfactory results were not obtained for differentiation between DC and OKC. Therefore, we performed a decision tree analysis.

RESULTS

The imaging characteristics of the lesions were significantly different according to Fisher's exact test, except for differences in sex. The ADC values statistically discriminated the lesions of DC and UAB, OKC and UAB, but not DC and OKC. Thus, differentiation was performed by a decision tree for DC and OKC by evaluating the following points: the attached tooth condition, signal intensity on the T₁ weighted image (T₁SI), ADC value, and the cyst site. However, cases showing hypo- or isointense T₁SI with an ADC value under 1.168 × 10^-3 mm²/s were difficult to differentiate.

CONCLUSION

The ADC value helped distinguish UAB from both DC and OKC, but not DC from OKC. However, the decision tree based on ADC value, tooth contact status, and T₁SI helped differentiate DC and OKC to some extent.

Cross-sectional observational study evaluating the association between odontogenic cystic content and size

OBJECTIVES

To evaluate and correlate the cystic content and the size of odontogenic cysts.

METHODS

The study included 29 cases of odontogenic cysts reported in the Outpatient Department of Sharad Pawar Dental College. The cystic aspirate was analyzed for levels of sodium, potassium, calcium, chloride, total protein, globulin, albumin, and cholesterol. The sodium/potassium ratio was calculated. Pearson's correlation coefficient (ρ) was used to correlate the size of the cyst with the sodium/potassium ratio and other cystic contents. P < 0.05 was considered statistically significant.

RESULTS

A positive and statistically significant correlation (ρ = 0.625, p = 0.020) was noted between the sodium to potassium ratio and the size of the cyst. The correlation between the other cystic contents and the size of the cyst was not statistically significant (p > 0.05).

CONCLUSION

The sodium to potassium ratio is positively correlated with the radiographic size of cysts. A thorough analysis of cystic fluid components could provide valuable insights into the potential expansion of odontogenic cysts.

Diagnosing the most common odontogenic cystic and osseous lesions of the jaws for the practicing pathologist

Odontogenic cysts and osseous lesions are often seen as challenging diagnostic lesions but the majority of them are easily classified. This article outlines the diagnostic features required for separating the most common of odontogenic cysts and select osseous lesions of the jaws. Clinical and radiographic findings of these jaw lesions often lead to a differential diagnosis that only the histologic findings will clarify. Dentigerous cyst, keratocystic odontogenic tumor, and certain ameloblastomas that have cystic change, may have identical radiographic findings, with only separation by their specific histologic features leading to the significantly different treatments required for each. Conversely, some cystic lesions can appear histologically identical and cannot be diagnosed without the radiographic findings. Certain osseous lesions of the jaws are particularly problematic for diagnosis without the appropriate radiographic findings, and the diagnosis should probably not be attempted on the histologic findings alone. This article will integrate the necessary clinical, radiographic, and histologic findings required to address the most common odontogenic lesions.

Biochemical and Cytological Comparison of Keratocystic Odontogenic Tumours to Nonkeratinising Odontogenic Cysts Fluid

AIM

To evaluate the levels of albumin, prealbumin, total protein, inorganic phosphate and presence of keratinocytes in the cystic fluid for the diagnosis and appropriate treatment planning of keratocystic odontogenic tumours and other non keratinizing odontogenic cysts.

MATERIALS AND METHODS

Fifteen keratocystic odontogenic tumour and 15 controls were studied. The cystic fluid was aspirated and analysed to determine the levels of albumin, prealbumin, total protein, inorganic phosphate and the presence of keratinocytes. The data collected was statistically evaluated using Mann Whitney U-Test and Student's t-test.

RESULTS

A highly significant difference (p<0.0001) was seen when a comparison of Prealbumin, total protein, inorganic phosphate and presence of keratinocytes was made between keratocystic odontogenic tumour and non keratinizing odontogenic cysts. The presence of albumin also showed a significant difference (p<0.01).

CONCLUSION

A combined analysis of total protein, albumin, prealbumin, inorganic phosphorous and detection of epithelial squames may be used as a diagnostic adjunct in the preoperative diagnosis of keratocystic odontogenic tumour in a minimally invasive and highly accurate fashion.

Keratocystic odontogenic tumour: systematic review

OBJECTIVES

The aim of this review is to evaluate the principal clinical and conventional radiographic features of non-syndromic keratocystic odontogenic tumour (KCOT) by systematic review (SR), and to compare the frequencies between four global groups.

METHODS

The databases searched were the PubMed interface of Medline and LILACS. Only those reports of KCOTs that occurred in a series of consecutive cases, in the reporting authors' caseload, were considered.

RESULTS

51 reports, of 49 series of cases, were included in the SR. 11 SR-included series were in languages other than English. KCOTs affected males more frequently and were three times more prevalent in the mandible. Although the mean age at first presentation was 37 years, the largest proportion of cases first presented in the third decade. The main symptom was swelling. Over a third were found incidentally. Nearly two-thirds displayed buccolingual expansion. Over a quarter of cases recurred. Only a quarter of all SR-included reported series of cases included details of at least one radiological feature. The East Asian global group presented significantly as well-defined, even corticated, multilocular radiolucencies with buccolingual expansion. The KCOTs affecting the Western global group significantly displayed an association with unerupted teeth.

CONCLUSIONS

Long-term follow-up of large series that would have revealed detailed radiographic description and long-term outcomes of non-syndromic KCOT was lacking.

The aggressive nature of the odontogenic keratocyst: is it a benign cystic neoplasm? Part 1. Clinical and early experimental evidence of aggressive behaviour

In this, the first of three articles on the aggressive nature of the odontogenic keratocyst (OKC), there is a review of clinical and histological observations which indicated that this was an aggressive lesion with a predilection for recurrence unlike the majority of other jaw cysts. This led to the tentative suggestion that the OKC might be a benign neoplasm. Subsequently there were early laboratory investigations that compared proliferation rates of the OKC epithelium with other jaw cysts, comparative enzyme histochemistry to assess aspects of its metabolism and markers that would enable accurate presurgical diagnosis of this cyst. Comparative studies were also pursued on the walls of the OKC and other jaw cysts to identify factors that might influence the capacity of the OKC to resorb the bone surrounding it. The clinical and laboratory studies reviewed in this section provided cogent presumptive evidence of the distinctively aggressive nature of the OKC that led numbers of investigators to pursue immunocytochemical and genetic studies on this cyst. Parts 2 and 3 of this series review this work.

Odontogenic keratocysts: clinicopathologic study of 87 cases

The clinical and histologic features of 87 cases of odontogenic keratocysts were reviewed. Males were affected more frequently than females. All age groups were affected, with a predilection for the fifth and sixth decades. The molar-angle-ramus area of the mandible was the most common location (29.8%). In 7 cases (8.8%), the cysts were part of the basal cell nevus syndrome. Recurrences were observed in 9 cases (10.4%). The cysts were lined by a thin, regular, stratified squamous, parakeratinized epithelium without rete ridges. Orthokeratin was observed in 24.14% of the cases. Mitotic figures were observed in approximately 50% of the cases. Separation of lining epithelium from underlying connective tissue was observed in 82.7%, with subepithelial hyalinization in 75.8% of the cases. Inflammation was observed in 72.4%, cholesterol clefts were observed in 11.5%, and Rushton hyaline bodies in 4.6% of the cases. Dental lamina rests were observed in 32.2% and satellite cysts in 20.7%. Dystrophic calcifications were found in 36.8%. Ameloblastomatous proliferation was observed in 2 cases.

Lactoferrin in aspirates of odontogenic cyst fluid

The possibility that the presence of lactoferrin in aspirates of odontogenic cyst fluid might be a useful preoperative diagnostic marker for odontogenic keratocyst was investigated. Using qualitative and quantitative immunodiffusion methods fluid from 29 of 29 dental (radicular) cysts, 12 of 14 dentigerous cysts and 27 of 31 keratocysts were found to contain lactoferrin. Although some of the highest concentrations of lactoferrin were detected in fluids from keratocysts, there was no significant difference between lactoferrin concentrations among the three groups. Neutrophil elastase was detected in 20 of 24 samples tested, 22 of which also contained lactoferrin. Immunocytochemical localisation of both lactoferrin and elastase was confined to neutrophils infiltrating cyst walls. These results suggest that lactoferrin in fluid from odontogenic cysts is derived from infiltrating neutrophils and that its presence in aspirated fluids is not a useful diagnostic marker for odontogenic keratocyst.

Recurrence of keratocysts. A long-term follow-up study

The aim of the study was to investigate the recurrence rate of keratocysts based on a material with a follow-up of at least 5 years, and to evaluate the relationship between different features of these cysts and their recurrence. It was found that of 75 keratocysts with follow-up times ranging from 5 to 17 years (mean 8.3), 32 (43%) recurred. The cumulative recurrence rate of the 67 annually examined cysts increased from 3% after the 1st year following the operation to 37% after the 3rd year. Thereafter, no new recurrences were noted. Recurrence of keratocysts in patients with basal cell nevus syndrome occurred more frequently than that of patients without the syndrome. Keratocysts enucleated in one piece recurred significantly less often than cysts enucleated in several pieces. The recurrence rate of keratocysts with a clinically observable infection, with fistula or with a perforated bony wall was higher than that of keratocysts without these features. Recurrence was also found more frequently in cysts with multilocular radiographic appearance than in unilocular cysts. The size or the location of the keratocysts did not have an influence on the recurrence rate.

Quantification and analysis of the glycosaminoglycans in human odontogenic cyst linings

Glycosaminoglycans (GAG) were extracted from the connective tissue of 15 dental cysts, 2 dentigerous cysts and 7 keratocysts, and separated electrophoretically and chromatographically. Hyaluronic acid (dental, 2.38; dentigerous, 3.98; keratocyst, 3.19 micrograms uronic acid/mg lyophilized tissue) was the major GAG detected, with lesser amounts of heparin (dental, 1.70; dentigerous, 1.95; keratocyst, 1.80 micrograms uronic acid/mg lyophilized tissue) and chrondroitin-4-sulphate (dental, 1.33; dentigerous, 2.85; keratocyst, 1.37 micrograms uronic acid/mg lyophilized tissue). It is suggested that enzymic release of these GAGs allows their diffusion into the luminal fluid where they may contribute to expansile cyst growth.

An immunocytochemical study of the inflammatory cell infiltrate and epithelial expression of HLA-DR in odontogenic cysts

The presence and distribution of lymphocytes, Langerhans cells, HLA-DR+ infiltrating cells and the expression of HLA-DR by lining epithelium was investigated in the walls of odontogenic cysts using an indirect immunoperoxidase method on acetone-fixed cryostat sections. The 23 cysts studied consisted of 14 dental (radicular) cysts, 5 keratocysts, 2 dentigerous cysts, 1 surgical ciliated cyst and 1 incisive canal cyst. The cell populations detected in the walls of all cysts were similar and consisted of HLA-DR+ macrophage-type cells and a mixture of T and B lymphocytes. Analysis of the T cell subsets revealed that in all cases the CD4+, Th/i subset predominated over the CD8+, Ts/c subset. 18/22 cyst linings contained cells expressing a Langerhans cell phenotype (CD1+). Cytoplasmic epithelial expression of HLA-DR was detected in 7/22 specimens. Neither the presence of HLA-DR+ epithelial cells nor LC were restricted to a given type of cyst. These findings indicate the occurrence of similar cellular processes irrespective of the proposed developmental or inflammatory aetiology of these lesions.

Immunoglobulin-producing cells in human odontogenic cysts

Immunohistochemical staining of immunoglobulin-containing plasma cells was performed on odontogenic keratocysts, dental (periapical) and dentigerous cysts. IgG-containing plasma cells were the predominant species in all cyst types examined, with a much lower percentage of IgA- and few IgM-containing plasma cells. Statistically significant differences in the percentage contributions of IgG and IgA plasma cells were observed between the keratocyst and both the dental (periapical) and dentigerous cysts and for IgM between the keratocyst and dental (periapical) cyst. Intense extracellular staining was observed for IgG in all cyst types.

A protein of squamous keratinising epithelium from odontogenic keratocyst fluid

Fluid from odontogenic keratocysts was analysed. The major protein fraction with a mobility anodal to albumin on electrophoresis was shown not to be albumin or pre-albumin but a non-serum protein. Using an antiserum to keratocyst fluid absorbed with human serum, non-serum components of the odontogenic keratocyst fluid were localised in squamous keratinising epithelia, principally in the upper layers. The same antiserum showed immuno-localisation in squamous cell carcinoma of skin and cervix. No localisation was seen in normal non-squamous epithelia, in liver, stomach and colon or in non-keratinising squamous epithelial cysts of the jaw.

Scanning electron microscopic observations on the inner surface of jaw cysts

The cavity surface of 9 jaw cysts was studied in the scanning electron microscope. The material comprised 5 radicular, 2 residual, 1 dentigerous and 1 globulomaxillary cyst. The surface morphology varied from smooth to ruffled within the same cyst, and between cysts. Interepithelial spaces, some of which contained migrating leukocytes, were frequently observed. Bacteria occurred in 1 cyst (dentigerous) only, and included rods, filaments and spirochetes. Crystals of various morphology were seen in 6 of the cysts.

The demonstration of alpha 1 antitrypsin in periapical lesions

Discontinuous vertical gel electrophoresis was applied to samples of root canal aspirate, periapical blood, and control blood from twelve periapical lesions. The periapical sample from ten of the twelve lesions showed an additional band in the alpha 1 globulin area which was not present in the control. By means of Grabbar-Williams immunoelectrophoresis to specific antisera, the band was subsequently identified as alpha 1 antitrypsin. The results suggest that the regulation of proteolytic activity afforded by alpha 1 antitrypsin plays an important role in the pathogenesis of periapical lesions.

Odontogenic keratocysts: a clinical and histological study with special reference to enzyme histochemistry

Of a total of 1,420 odontogenic cysts, 52 (3.3%) were diagnosed as odontogenic keratocysts. Clinical and histological findings in these 52 cysts are reported. Frozen sections of 26 of the keratocysts were incubated to show the following enzyme activities: NADH2- and NADPH2-diaphorase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, acid phosphatase, leucine aminopeptidase and ATPase. Furthermore, keratinization was studied with the rhodamine B method and lipids with the oil red O, the OTAN and the acid hematein methods. Sections from epidermis, oral mucosa, radicular cysts, residual cysts and follicular cysts served as reference material. The oxidative enzymes showed strong activity in the keratocyst epithelium which contrasted with weak activity in the reference cysts. Acid phosphatase activity was weak in all epithelia except that in keratocysts, which displayed a marked activity. In the fibrous capsule of the keratocyst a high activity of leucine aminopeptidase was recorded. This high activity contrasted with a weak activity in the reference material. The significance of the histochemical results in relation to the aggressive behavior of the keratocyst is discussed.

Soluble proteins in fluid from non-keratinizing jaw cysts in man

Fluids from non-keratinizing cysts of the jaws contain the main proteins found in plasma. The low relative concentration of macromolecular non-immunoglobulin proteins shows that there is no free passage of plasma proteins into the cyst fluid. Sufficient evidence was found to conclude that the immunoglobulins in cyst fluid are partly produced locally and partly derived from plasma. Cyst fluid immunoglobulins have antibody activity to rabbit erythrocytes. Accumulation of cyst fluid is primarily due to inadequate lymphatic drainage of the cyst cavity. Differential diagnosis between various types of non-keratinizing cysts cannot be based on the plasma protein patterns of their fluids.