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Although ameloblastoma and adenomatoid odontogenic tumor (AOT) belong to the same group according to the World Health Organization, they show different biologic behaviors. PCNA, an amplifier of cell proliferation, and p53, a tumor suppressor protein, are overexpressed in some odontogenic lesions. The purpose of this study was to immunohistochemically evaluate the expression of p53 and PCNA to clarify the possible role of these proteins in different behaviors of ameloblastoma and AOT. The immunohistochemical expression of PCNA and p53 was determined in 30 solid ameloblastomas and 12 AOTs. Statistical tests including one-way ANOVA, t-test, chi-square, Mann-Whitney U and Kendall were used to analyze the data. All tissue sections (except one specimen of plexiform ameloblastoma) exhibited immunoexpression for p53. PCNA was expressed in all specimens. There was no significant difference in PCNA expression between ameloblastomas and AOTs (P > 0.05). For p53, there was no statistical difference between subtypes of ameloblastomas (P > 0.05), whereas statistical differences were observed between ameloblastomas and AOTs (P < 0.001). There was no statistical difference in PCNA intensity of staining between ameloblastomas and AOTs (P > 0.05), whereas the p53 intensity in ameloblastomas was stronger than AOTs (P < 0.05). Positive correlation between PCNA and p53 was observed. We concluded that PCNA overexpression is not responsible for the difference in clinical behavior of these two lesions, whereas the expression of p53 in ameloblastoma may explain the more aggressive nature of this tumor compared with AOT.

Calcifying odontogenic cyst (COC) is adevelopmental odontogenic cyst in the jaw. Because of its diverse histopathologic features and biological behavior, there has long been confusion with regard to its nature as a cyst or neoplasm. This study evaluated the proliferative activity of 57 COC samples, including simple cyst (10 cases), cystic neoplasm (34 cases), solid neoplasm (6 cases) and combined lesion (7 cases) by p53 and PCNA immunohistochemical staining. For assessment of p53 and PCNA positivity, the number of positively stained cells with brown-stained nuclei was counted in 1000 cells from each sample. p53 and PCNA expression in the solid neoplasm subtype were significantly higher when compared to cystic neoplasm and simple cyst (P < 0.05). The lowest p53 and PCNA expression was found in the simple cyst subtype. p53 and PCNA expression in the basal and suprabasal layers was significantly higher in the solid subtype when compared to others, and the difference between COC groups was significant. The results demonstrated that within benign types of COC, the amount of p53 and PCNA in proliferative epithelium is significantly higher when compared to non-proliferative epithelium.

Sebaceous adenoma of the salivary gland is a rare tumor comprising 0.1% of all salivary gland neoplasms and less than 0.5% of salivary adenomas. Histologically, sebaceous adenomas are benign neoplasms consisting of sebaceous cells arranged in nests forming acinar and duct-like structures. Oncocytic metaplasia may also occur in some areas. We describe a case of sebaceous adenoma in the submandibular gland. Under a presumptive diagnosis of sialadenitis/sialolithiasis, the patient was administered multiple courses of antibiotics; however, these were not effective. Excisional biopsy resulted in a diagnosis of sebaceous adenoma. A 1-year follow-up showed no recurrence.

Abstract:Objective: The purpose of this study was to retrospectively analyze the demographic characteristics of patients with central giant cell granulomas (CGCGs) and peripheral giant cell granulomas (PGCGs) in Iranian population. Methods: The data were obtained from records of 1019 patients with CGCG and PGCG of the jaws referred to our department between 1972 and 2010. This 38-year retrospective study was based on existing data. Information regarding age distribution, gender, location of the lesion and clinical signs and symptoms was documented. Results: A total of 1019 patients were affected GCGLs including 435 CGCGs and 584 PGCGs during the study. The mean age was 28.91 ± 18.16. PGCGs and CGCGs had a peak of occurrence in the first and second decade of life respectively. A female predominance was shown in CGCG cases (57.70%), whereas PGCGs were more frequent in males (50.85%). Five hundred and ninety-eight cases of all giant cell lesions (58.7 %) occurred in the mandible. Posterior mandible was the most frequent site for both CGCG and PGCG cases. The second most common site for PGCG was posterior maxilla (21%), whereas anterior mandible was involved in CGCG (19.45%). The majority of patients were asymptomatic. Conclusions: In contrast to most of previous studies PGCGs occur more common in the first decade and also more frequently in male patients. Although the CGCGs share some histopathologic similarities with PGCGs, differences in demographic features may be observed in different populations which may help in the diagnosis and management of these lesions.