Scanning electron microscopic studies and x-ray microanalysis of hyaline bodies in odontogenic cysts

70 odontogenic cysts with hyaline bodies (HB) were examined by light and scanning electron microscopy. The scanning electron microscopic studies were performed on dried tissue material, which had been previously examined by light microscopy and energy dispersive x-ray analysis of the histologic sections. The form and basic structure of both the early forms of HB as well as the HB Type I and II could be identified more closely. The early forms, the outer component of the HB Type II and the inner and outer component of the HB Type I consisted of a fine-grained substance, which presumably goes through varying "partial homogenization", thus giving the HB an increased firmness and elasticity. The HB are a product of the epithelium of odontogenic cysts and have direct contact to the outer layer of the adjacent cyst epithelium via its intercellular bridges.     

Ameloblastomas originating from odontogenic cysts

Three case histories are presented in which solid intraosseous ameloblastomas developed at the site of histologically verified odontogenic cysts.     

Mast cells in human odontogenic cysts

Mast cells have been shown to be present in substantial numbers in both nonkeratinizing and keratinizing odontogenic cysts and could be seen in the connective tissue capsule and the epithelial lining. Within the cyst capsule, mast cells were more prevalent just beneath the epithelium than in deeper areas. This distribution pattern for mast cells is in accord with the histochemical picture for heparin staining in odontogenic cysts. In the non-keratinizing cysts, there appeared to be some trend towards mast cells being associated with increasing inflammation but not in the odontogenic keratocyst. No evidence could be found for distinct mast cell subpopulations in odontogenic cysts. The presence of mast cells in odontogenic cyst could contribute to their pathogenesis in several ways.     

Epidermal growth factor receptor in odontogenic cysts and tumors

The expression of epidermal growth factor receptor (EGFR) was investigated in 67 cases of odontogenic cysts and 35 cases of odontogenic tumors using monoclonal antibody to EGFR (Biomarker, Israel) to determine the presence and significance of this transmembrane growth factor receptor. The cystic epithelial cells of odontogenic cystic lesions (keratocyst 60%; primordial cyst 75%; radicular cyst 35%; and follicular cyst 47.4%) were positive to EGFR staining. Cytochemical characterization of EGFR in those cystic epithelium was cell membrane positive type as in the normal epithelium. No expression of EGFR was found in the odontogenic tumors. This diversity of EGFR represents no binding activity of EGF, or loss of EGFR in the tumor cell upon EGFR mediated growth in odontogenic tumors was suggested a different tumor cell growth factor status or microenvironment in cell proliferation mechanism at the cellular level in cysts and tumors of odontogenic origin.     

Evaluation of mast cells in periapical cysts, dentigerous cysts, and keratocystic odontogenic tumors

J Oral Pathol Med (2012) 41 : 630–636 Background: Several cell types are associated with the development of cystic and tumoral odontogenic lesions. Among inflammatory cells, mast cells can be associated with their pathogenesis. The aim of this study was to analyze mast cells in periapical cysts, dentigerous cysts, and keratocystic odontogenic tumors. Methods: Tissue sections were submitted to toluidine blue staining and immunohistochemistry with antibody anti‐tryptase (clone G3). Mast cells were quantitated using Image‐Pro Plus software to obtain the mean number of mast cells in three regions: epithelial, superficial portion of the fibrous wall and deep portion of the fibrous wall from 20 periapical cysts, 20 dentigerous cysts (six non‐inflamed and 14 inflamed) and 20 keratocystic odontogenic tumors (four non‐inflamed and 16 inflamed). Results: The mean number of mast cells detected per lesion by immunohistochemistry (4.1) was higher than by histochemistry (1.5) (P < 0.0001). Inflamed dentigerous cysts and keratocystic odontogenic tumors showed a higher mean number of mast cells than non‐inflamed lesions in all regions. The deep region from all cysts showed the highest mean number of degranulated mast cells, except for non‐inflamed keratocystic odontogenic tumors analyzed by immunohistochemistry. Conclusions: Immunohistochemical staining detected higher number of mast cells than histochemistry. The higher number of mast cells observed in inflamed lesions could indicate the participation of these cells in the inflammatory response in odontogenic lesions. The prevalence of degranulated mast cells in the deep region suggests intense activity of these cells, possibly related to growth of cystic lesions.     

Pigmented lateral periodontal cyst and other pigmented odontogenic lesions

OBJECTIVE: To report a case of lateral periodontal cyst (LPC) with marked melanin pigmentation in a 38-year-old Black male and to discuss the phenomenon of melanin pigmentation in odontogenic cysts and tumors.
RESULTS: Histologically, the epithelial lining of the LPC contained an abundant amount of melanin granules throughout the entire epithelium. Ultrastructurally, epithelial cells contained mature melanosomes (stage IV melanosomes). Melanophages containing aggregates of melanosomes were identified in the connective tissue cyst wall. Perusal of the literature revealed that melanin pigmentation in odontogenic lesions is uncommon. Melanin has been reported in calcifying odontogenic cyst (18 cases), odontogenic keratocyst (8 cases), adenomatoid odontogenic tumor (3 cases), ameloblastic fibroma (3 cases), odontoma (2 cases), and amelobastic fibro-odon-toma, odonto-ameloblastoma, and odontogenic fibroma (I case each).
CONCLUSIONS: Almost all pigmented odontogenic lesions occurred in Blacks and Asians; they are almost non-existent in Whites. Thus, racial pigmentation probably plays an important role in such lesions.     

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由于颌骨内的成牙组织常可作为囊肿和肿瘤的组织来源,因此颌骨是人类骨骼中最好发上皮性囊肿和肿瘤的部位。这类牙源性病损好发于年轻人,可造成颌骨及邻近组织的破坏,导致口腔颌面部外形改变,某些侵袭性病损具有较高的复发倾向,可对患者的生存质量及心理健康造成严重影响。本文着重讨论几种常见的牙源性囊肿与牙源性肿瘤的病理学诊断。     

p53 and MDM2 expression in odontogenic cysts and tumours

OBJECTIVE: The aim of this report was to assess p53 and MDM2 expression in odontogenic cysts and tumours, as they are known to play important roles in cell proliferation and tumorigenesis. MATERIALS AND METHODS: The expression of p53 and MDM2 proteins was determined immunohistochemically in 51 formalin-fixed, paraffin embedded specimens of odontogenic cysts and tumours.RESULTS: No positivity to p53 was found in the cases studied. MDM2 expression in ameloblastoma was higher than in radicular cysts, but lower than that observed in odontogenic keratocysts. No difference was observed between MDM2 expression in radicular cyst and adenomatoid odontogenic tumour. The clear-cell odontogenic ameloblastoma presented strong immunoreaction to this antigen.CONCLUSIONS: The results suggest that MDM2 overexpression may be involved in the pathogenesis of some odontogenic lesions.     

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牙源性囊肿与牙源性肿瘤是口腔颌面部较为常见的疾病。由于临床表现的多样性,易与其他类型的颌面部囊肿或肿瘤相混淆,而且不同类型的牙源性囊肿和肿瘤其治疗方案也有所区别,所以牙源性囊肿及肿瘤的术前诊断对于其治疗方案的选择起着关键的作用,而在其诊治的过程中,影像学检查起到了非常重要的作用;不同类型的牙源性囊肿及肿瘤的影像学表现也各具特征。本文对常见的牙源性囊肿(牙源性角化囊肿等)及肿瘤(成釉细胞瘤、恶性成釉细胞瘤等)的影像学表现结合实际的影像学图片作简单的介绍,比较各种影像学检查在上述疾病诊断中所具有的优点,以期望能将CT、MRI及全景片等影像学检查手段更好的运用于上述疾病的诊治中。     

Immunoexpression of keratins in the calcifying cystic odontogenic tumor epithelium

Ameloblastomatous epithelium containing clusters of ghost cells is the typical histopathology of calcifying cystic odontogenic tumor (CCOT). This paper aimed to assess keratins AE1‐AE3, K7, K10/13, K14, K18, K19, vimentin, laminin, and collagen IV in 08 CCOTs to discuss their histopathogenesis. Similarity to the immunoprofile of the stratified squamous epithelium was seen in the with the basal layer expressing K14 and the upper cells expressing K10/13. When compared to the immunoprofile of the normal odontogenic epithelium, of odontogenic tumor epithelia and of the ghost cells described in the literature, it was possible to suggest that the CCOT epithelium differentiates towards squamous type.     

A variant of calcifying epithelial odontogenic tumor with Langerhans cells

A variant of calcifying epithelial odontogenic tumor (CEOT) with Langerhans cells is reported. Compared to a typical CEOT, the tumor islands of this case were thin and composed of a small number of polyhedral epithelial cells. Almost no calcification of homogeneous eosinophilic materials was observed. In addition, clear cells which structurally corresponded to Langerhans cell were intermingled in the epithelial islands. These cells stain positively for S-100 protein, lysozome, MT 1, LN-3 and OKT 6 antibodies, but not for keratin antibody. Electronmicroscopic examination revealed the rod-shaped and racket-shaped structures called Birbeck's granules in the cytoplasm of these clear cells. Our observations indicate a variant case of CEOT with Langerhans cells in tumor nests.     

Glandular odontogenic cyst: a challenge in diagnosis and treatment

The present review analyzes the accumulated data from all cases of glandular odontogenic cyst (GOC) reported in the English language literature. In the 20 years since it was first described, 111 cases have been reported, an incidence of 0.2% of odontogenic cysts. The age range is 14-75, mean 45.7, with a M/F ratio of 1.3:1. GOC has a predilection for the mandible (70%), affecting both anterior and posterior areas. It is typically radiolucent, well defined, either unilocular (53.8%) or multilocular (46.2%). Frequent perforation (61%) and of thinning of cortical plates (24.4%) indicate aggressiveness. Sufficient follow-up indicates that 30% of cases can recur. Treatment by enucleation or curettage carries the highest risk for recurrence, especially in large and multilocular lesions. Peripheral osteoectomy or marginal resection can eliminate the risk. Defined criteria for microscopic diagnosis are described, which in addition to Ki67 and p53 can help in differentiating GOC from lesions with histological similarities (cysts with mucous metaplasia, botryoid and surgical ciliated cysts, low-grade mucoepidermoid carcinoma). Definite diagnosis may not be possible in small incisional biopsies due to the focal presentation of characteristic features required for diagnosis. There is now evidence to support an odontogenic rather than a sialogenic origin.     

Adenomatoid odontogenic tumorlike lesion in a male Wistar rat

An odontogenic tumor in the maxilla of a male Wistar rat is described. The tumor consisted of large epithelial areas with peripheral palissading and with juxtaepithelial material resembling dentin. The neoplastic odontogenic epithelium seems capable of inducing peridental mesenchyme to form a kind of dental hard tissue normally not present at that site.     

Prevalence of developmental odontogenic cysts in children and adolescents with emphasis on dentigerous cyst and odontogenic keratocyst (keratocystic odontogenic tumor)

Objective. To investigate the incidence and prevalence of developmental odontogenic cysts in children and adolescents and compare the features of the two most common types, dentigerous cyst and keratocystic odontogenic tumor (KCOT). Study design. A retrospective review in a series of 369 patients with all histological diagnoses of developmental odontogenic cysts in children (≤12 years) and adolescents (13–18 years) was conducted. Results. Among these, 361 (97.8%) patients were diagnosed as dentigerous cyst (n = 281) and KCOT (n = 80), with the male-to-female ratios of dentigerous cyst and KCOT both being 2:1. The average age of the patients with KCOT was older than that of those with dentigerous cyst (14.7 years vs 11.8 years, p < 0.001). Dentigerous cyst (59.1%) was more common in children, but KCOT (78.8%) was more common in adolescents (p < 0.001). Dentigerous cyst (57.6%) predominantly located on the maxilla, but KCOT (60.3%) predominantly located on the mandible (p = 0.010). Conclusions. Adolescent patients with lesions located on the mandible would favor KCOT over dentigerous cyst. This study aids in better knowledge of the prevalence of developmental odontogenic cysts in a large pediatric population, and shows that a well-supported early diagnosis is indispensable for a more adequate treatment.     

Quantification of PCNA+ cells within odontogenic jaw cyst epithelium

The aim of this study was to investigate the reactivity of the epithelial linings of the three major types of odontogenic cyst with a monoclonal antibody to proliferating cell nuclear antigen (PCNA; clone PC 10). PCNA expression was studied in odontogenic cysts (n=31) and normal oral epithelium (n= 10) using a biotin-streptavidin method on routinely processed paraffin sections. PCNA⁺ cells were counted manually and related to the length of basement membrane (mm) and the epithelial area (mm²) as determined by TV image analysis. The epithelial linings of odontogenic keratocysts (OKC; n= 11) contained the highest number of PCNA⁺ cells, most of which were located in the suprabasal layers. The mean value of PCNA⁺ cells in OKC linings (94.4 ±22.7 cells/mm) was similar to that of oral epithelia (80.8 ± 20.6 cells/mm), but both were significantly higher than that of dentigerous (n = 10. 5.1 ± 3.0 cells mm) and radicular (n = 10, 11.0 ± 4.1 cells /mm) cyst linings (P- 0.005). The epithelial distribution of PCNA⁺ cells differed between groups with the basal/suprabasal PCNA⁺ cell ratio in OKC linings (0.05 ± 0.02) being significantly lower than that of normal oral epithelium (0.5 ± 0.14), dentigerous (l.6 ± 1.23) and radicular (l.9 ± 1.09) cyst linings respectively (P < 0.005). These results demonstrate differences in PCNA⁺ expression between the epithelial linings of the major odontogenic cyst types, indicating differences in proliferative and differentiation processes within these lesions.