Orthokeratinised odontogenic keratocysts in Malaysians

The records of the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, Malaysia, were reviewed for the incidence of odontogenic keratocysts of the orthokeratinised variety, during the 20-year-period, 1967 to 1986. Nine cases were found. The clinical, histological and radiological features of these cases are reported. Many features were similar to previous reports of this entity but a peak incidence in the second decade of life, an almost even distribution in the maxilla and mandible, and a distinct predilection for the Chinese were observed. It is suggested that these features may be peculiar to Malaysians.     

Calcifying epithelial odontogenic tumour associated with dentigerous cyst

A case of calcifying epithelial odontogenic tumour is described. Provisional diagnosis based on the radiographical and clinical observations was that of a dentigerous cyst. Microscopical examination revealed features similar to that of CEOT in addition to the epithelial cyst lining.     

Calcifying epithelial odontogenic tumour or Pindborg's tumour: features and behaviour in relation to a case

The calcifying epithelial odontogenic tumour (CEOT) or Pindborg's tumour is a rare benign odontogenic neoplasm composed of epithelioid cells, amorphous amyloid-like substance and calcifications. Its clinical and radiographical pictures are not characteristic depending upon the site, size and developmental stages in a range of its composition degeneration. A case of calcifying epithelial odontogenic tumour in the mandible is presented and the main aspects of the research about this tumour, such as the pathogenesis, histological features, developmental stages, malignancy, recurrence rate, differential diagnosis and therapeutic aspects are discussed.     

Calcifying epithelial odontogenic tumour: a case showing features of malignancy

A case of malignant calcifying epithelial odontogenic tumour is reported in a 75-year-old man. Evidence of local tissue invasion and lymph-node metastasis is presented. Immunoperoxidase studies of the neoplastic cells and tumour amyloid were negative for a variety of antigens, including the epithelial markers CEA and keratin. The histological and clinical findings are discussed.     

Malignant transformation of calcifying epithelial odontogenic tumour with solitary pulmonary metastasis

This report describes the management of a case of calcifying epithelial odontogenic tumour (CEOT) that underwent malignant transformation and metastasized to the lung. The solitary pulmonary metastasis was discovered incidentally on computed tomography (CT) imaging of the neck. It appears that only one previous case with proven pulmonary metastasis has been reported in the literature, which involved multiple pulmonary deposits managed with platinum chemotherapy. The long-term prognosis of metastatic CEOT is therefore unknown. In the case presented here, the patient was managed successfully with surgery alone. There is often diagnostic uncertainty because histological features of benign, recurrent, and malignant CEOT are not dissimilar. Ki-67 immunohistochemistry is helpful, as higher levels are more indicative of malignancy. We consider that in cases of suspected recurrent and malignant CEOT, CT imaging of the thorax and abdomen as part of follow-up may identify metastases early, resulting in earlier treatment, an improved prognosis, and reduced morbidity and mortality.     

Calcifying epithelial odontogenic tumour: a case showing features of malignancy

A case of malignant calcifying epithelial odontogenic tumour is reported in a 75–year-old man. Evidence of local tissue invasion and lymph-node metastasis is presented. Immunoperoxidase studies of the neoplastic cells and tumour amyloid were negative for a variety of antigens, including the epithelial markers CEA and keratin. The histological and clinical findings are discussed.     

The nature of the amyloid-like material in a calcifying epithelial odontogenic tumour: an ultrastructural study

An ultrastructural study was carried out to investigate the nature of an eosinophilic material, having the staining properties of amyloid, in a case of calcifying epithelial odontogenic tumour. At the electron-microscopical level, the eosinophilic masses consisted of two types of structure which are probably related. The first type appeared as sheets of fine filaments measuring 10–12 nm in diameter. The second type was in the form of aggregates of lamina densa fragments, probably secreted by the tumour epithelium. These fragments appeared to undergo some loss of electron density and became degraded into fine filaments, having similar thickness and electron density to those forming the filamentous masses. It is concluded from this study that the fine filamentous material is a form of amyloid which results from degradation of lamina densa material.     

Central calcifying epithelial odontogenic tumour in the posterior maxilla: a case report

The calcifying epithelial odontogenic tumour (CEOT), or Pindborg tumour, is a rare, benign odontogenic tumour. CEOT is usually asymptomatic and an incidental radiological finding, often presenting as a mandibular radiolucency with flecks of calcific material. We report an unusual case of CEOT in the left posterior maxilla of a 46‐year‐old male that was associated with an unerupted tooth. The tumour in this case caused non‐specific sinus symptoms and appeared radiographically similar to an odontoma or ossifying fibroma due to its dense calcific contents. Diagnosis was confirmed histologically following surgical removal of the lesion, which showed classic CEOT histomorphology. We report this case to highlight the unusual clinico‐radiologic presentation and illustrate the diagnostic difficulties that can occur with radiolucent and/or radiopaque lesions in the jaws.     

Combined epithelial odontogenic tumor: adenomatoid odontogenic tumor and calcifying epithelial odontogenic tumor

1. Two cases of a combined epithelial odontogenic tumor which had areas of AOT and CEOT were presented. 2. A review of the studies on histogenesis of the AOT revealed that the tumor probably consists of preameloblasts, stratum intermedium, and stellate reticulum. 3. A review of the studies on histogenesis of the CEOT revealed that the probable origin was in cells of stratum intermedium. 4. It is suggested that the present cases support the aforementioned theories of histogenesis and represent AOT's which contain foci of CEOT. 5. The suggested treatment is simple surgical excision.     

Calcifying epithelial odontogenic tumour presenting at a surgical site: case report

We describe the management of a calcifying epithelial odontogenic tumour with an atypical clinical presentation at the site of a previously surgically exposed impacted maxillary canine in a 51-year-old woman.     

Peripheral squamous odontogenic tumour

Squamous odontogenic tumour (SOT) is a rare, benign epithelial tumour of odontogenic origin. A recurrent case of SOT with peripheral occurrence is described. In 1971, a tumour from the anterior maxillary palatal mucosa of an 11-year-old female was excised. In 1984, when the patient was 24 years old, a recurrent tumour was found in the same area. The histopathological appearance of the lesion, which was found to be identical with the primary tumour, was that of an SOT. Both the clinical and radiographic features supported the extra-osseous involvement of both tumours. The SOT is further evaluated and its origin is discussed.     

磷酸化p38促分裂原活化的蛋白激酶、尿激酶型纤溶酶原激活物及Ki-67在牙源性上皮性肿瘤中的表达

目的 检测磷酸化p38促分裂原活化的蛋白激酶(phosphorylated-p38 mitogen-activated protein kinase,p-p38MAPK)、尿激酶型纤溶酶原激活物(urokinase plasminogen activator,uPA)及Ki-67在牙源性上皮性肿瘤中的表达,探讨p-p38MAPK对牙源性上皮性肿瘤细胞增殖活性及侵袭性的影响.方法 根据2005年WHO关于牙源性肿瘤的分类标准,应用免疫组化方法检测p-p38MAPK、uPA和Ki-67在成釉细胞瘤(ameloblastoma,AB)、牙源性角化囊性瘤(keratocystic odontogenic tumour,KCOT)、牙源性钙化上皮瘤(calcifying epithelial odontogenic tumor,CEOT)、牙源性腺样瘤(adenomatoid odontogenic tumour,AOT)及牙源性钙化囊性瘤(calcifying cystic odontogenic tumour,CCOT)(以上为肿瘤组)和5例牙胚(对照组)中的表达.结果 p-p38MAPK在肿瘤组的阳性表达率为26%(17/65),在肿瘤细胞胞质和胞核均可见着色;uPA在肿瘤组的阳性表达率为78%(51/65),主要表现为肿瘤细胞胞质着色;Ki-67在肿瘤组的阳性表达率为95%(62/65),为弥散的肿瘤细胞胞核着色.p-p38MAPK、uPA和Ki-67在牙源性上皮性肿瘤的阳性表达率显著高于对照组(P＜0.05),三者的阳性表达呈正相关(P＜0.05).结论 p-p38MAPK信号传导通路可能以正性调节的方式调控uPA从而促进牙源性上皮性肿瘤的发生,可能是肿瘤发生、侵袭和增殖的重要途径之一.     

Keratocystic odontogenic tumour: reclassification of the odontogenic keratocyst from cyst to tumour

The purpose of this paper is to review the features and behaviour of the odontogenic keratocyst (OKC), now officially known as the keratocystic odontogenic tumour (KCOT); to analyze a series of histologically confirmed KCOT cases; and to review and discuss the redesignation of KCOT and the implications for treatment. Redesignation of the OKC as the KCOT by the World Health Organization (WHO) is based on the well-known aggressive behaviour of this lesion, its histology and new information regarding its genetics. Abnormal function of PTCH, a tumour suppressor gene, is noted to be involved in both nevoid basal cell carcinoma syndrome and sporadic KCOTs. Normally, PTCH forms a receptor complex with the oncogene SMO for the SHH ligand. PTCH binding to SMO inhibits growth-signal transduction. SHH binding to PTCH releases inhibition of the signal transduction pathway. If normal functioning of PTCH is lost, the proliferation-stimulating effects of SMO are permitted to predominate. A review of the literature was conducted and results were tabulated to determine whether treatment modality is related to recurrence rate. More aggressive treatment - resection or enucleation supplemented with Carnoy"s solution with or without peripheral ostectomy - results in a lower recurrence rate than enucleation alone or marsupialization. Notably, the recurrence rate after marsupialization followed by enucleation is not significantly higher than that following the so-called aggressive modalities. Our case series consists of 21 patients treated for KCOTs. Results were organized to demonstrate recurrence as it relates to size of lesion and time since treatment and incidence as it relates to patient age and location in the jaws. In our series, the average KCOT surface area measured radiographically was 14 cm². Most lesions were within the 0-15 cm² range and lesions in this range resulted in the greatest number and proportion of recurrences. The recurrence rate of 29% in our case series was consistent with previously established data; all recurrences occurred within 2 years post-intervention. The incidence of primary lesions was highest in the age group 70-79 years; most lesions occurred in the posterior mandible. WHO"s reclassification of the OKC as the KCOT based on behaviour, histology and genetics underscores the aggressive nature of the lesion and should motivate clinicians to manage the disease in a correspondingly aggressive manner. The most effective interventions for the KCOT are either enucleation with Carnoy"s solution, or marsupialization with later cystectomy. Future treatment may involve molecular-based modalities, which may reduce or eliminate the need for aggressive surgical management.     

An investigation into the origin and nature of 'amyloid' in a calcifying epithelial odontogenic tumour

Fresh and fixed tissue from a resection specimen of a calcifying epithelial odontogenic tumour (CEOT) was prepared for histological, histochemical, immunological and biochemical investigation in order to study the nature of the amyloid-like material. The fixed tissue gave positive reactions with Congo-red, Thioflavin T and the dimethylamino benzene (DMAB)-method for tryptophan. The diazotization-coupling (DC) method for tyrosine was negative. The major protein purified from the unfixed tissue by sequential gel filtration had a molecular weight of 9,800. The amino acid analysis of this protein had similarities with tuft enamel protein, immune amyloid and the variable light chain component (VK). From the data obtained in this study, it is not possible to determine the precise nature of the amyloid-like material in this CEOT. However, the results do support the concept that 'amyloid' should be considered as a term describing a broad group of related proteins.     

An investigation into the origin and nature of 'amyloid' in a calcifying epithelial odontogenic tumour

Fresh and fixed tissue from a resection specimen of a calcifying epithelial odontogenic tumour (CEOT) was prepared for histological, histochemical, immunological and biochemical investigation in order to study the nature of the amyloid-like material. The fixed tissue gave positive reactions with Congo-red, Thioflavin T and the dimelhylamino benzene (DMAB)-method for tryptophan. The diazotization-coupling (DC) method for tyrosine was negative.
The major protein purified from the unfixed tissue by sequential gel filtration had a molecular weight of 9,800. The amino acid analysis of this protein had similarities with tuft enamel protein, immune amyloid and the variable light chain component (VK).
From the data obtained in this study, it is not possible to determine the precise nature of the amyloid-like material in this CEOT. However, the results do support the concept that 'amyloid' should be considered as a term describing a broad group of related proteins.