Hyaline ring granuloma of the mouth-A foreign-body reaction that dentists should be aware of: Critical review of literature and histochemical/immunohistochemical study of a new case.

Hyaline ring granuloma (HRG) is a rare and atypical foreign-body granulomatous chronic inflammatory condition. Our aim was to make a critical review of the literature cases and also to illustrate histochemical and immunohistochemical findings of a new case. A modified PICO strategy was used. Inclusion criteria were met by case reports and case series with a histologically confirmed diagnosis of HRG, necessarily in mouth or maxillary bones. Exclusion criteria were no access to the full-text paper. The search was done up to 2019, totalizing 231 selected cases in 54 papers. The new case was analyzed through PAS, Azan-Mallory's trichrome, and CD34 and CD68 reactions. HRG is found mainly in the mandible of men, edentulous and prosthesis users, between 51 and 60 years of age, with 0.5-120 months of duration, usually causing edema and pain or discomfort. Endogenous and exogenous theories may be complementary in HRG. Eosinophilic areas could represent particles of vegetal origin, while the hyaline material could be the result of collagen degradation. Considering the material is not always present or even is ring-shaped, we suggest the change from "hyaline ring granuloma" to "granuloma induced by vegetal inoculation."

A Brazilian multicentre study of 2,497 isolated cases of odontogenic keratocysts.

We present the frequency of cases of isolated odontogenic keratocysts submitted to microscopic examination at 10 Brazilian referral centres in Oral and Maxillofacial Pathology. In a retrospective (1953-2017) analysis, data on clinicoradiographic features and treatment of these lesions were collected and analysed descriptively. Among the 258,867 cases retrieved, 2,497 (0.96%) were isolated odontogenic keratocysts. In summary, an overview of individuals affected with isolated odontogenic keratocysts is reported herein. This lesion showed predilection for the posterior mandible of young adult men.

Influence of melaleuca and copaiba oils on Candida albicans adhesion.

OBJECTIVE: To evaluate the efficacy of Melaleuca alternifolia and Copaifera officinalis in inhibiting the adhesion of Candida albicans biofilm. BACKGROUND: Over 65% of denture wearers suffer from denture stomatitis, which is one of the most prevalent forms of oral candidiasis. This disease is characterised by the inflammation of the oral mucosa in contact with the contaminated denture. The contaminated denture contributes to the switch of C. albicans from yeast to its pathogenic hyphal form. Candida albicans adheres and colonises the polymethylmethacrylate resin surfaces and thus contributes to the development of denture stomatitis. MATERIALS AND METHODS: The minimal inhibitory concentration (MIC) of M. alternifolia and Co. officinalis was assessed by the agar dilution method. Sixty-six thermopolymerised acrylic resin squares were used and treated with phosphate-buffered saline, sodium hypochlorite 1%, melaleuca 0.75%, melaleuca 0.375%, melaleuca 0.188% and copaiba 10%. For adherence and biofilm formation, the treated squares were placed in six-well tissue culture plates containing 1 × 10(7)  cells/ml of ATCC1023 or SC5314 in Roswell Park Memorial Institute (RPMI) medium, and after 12 h, the planktonic cells were counted. RESULTS: Copaiba oil did not inhibit C. albicans growth. However, melaleuca oil showed an MIC value of 0.375% (3.4 mg/ml) for ATCC10231 and 0.093% (0.84 mg/ml) for SC5314. CONCLUSIONS: Our results demonstrated that M. alternifolia oil inhibited the growth of C. albicans. Moreover, both oils promoted significant adhesion reduction in the tested strains. These findings suggest the possibility of using these oils in prophylaxes against candidiasis.

Bilateral lipomatous hamartoma of the tongue: A case report in a child with oral-facial-digital syndrome type VI.

A hamartoma is a benign proliferation of typical mature cells specific to a particular anatomical site. In the oral cavity, they may occur as isolated cases or be associated with genetic syndromes. Oral-facial-digital syndrome type VI is a rare genetic disorder with an estimated incidence of one in 50,000-250,000 newborns. Here, we report a case of a 2-year-old boy diagnosed with oral-facial-digital syndrome type VI who was referred for evaluation of a bilateral and normochromic to slightly pinkish nodule on the lateral surface of the tongue. Clinically, the child presented hypotonia, low visual acuity, absence of oculocephalic reflex, delay in neuropsychomotor development, and polydactyly in the feet. Excisional biopsies of both sides of the tongue were performed using a 1.5 W high-power diode laser (wavelength of 980 nm), and histopathological analysis revealed abundant mature adipocytes predominantly arranged in lobules that mainly surrounded the minor salivary gland parenchyma. The surgical sites healed with no complications and the patient remains under follow-up for 10 months. Due to the limited literature on this syndrome and the frequent presence of tongue hamartomas in children, dentists need to be familiar with them.

Expression of odontogenic ameloblast-associated protein, amelotin, ameloblastin, and amelogenin in odontogenic tumors: immunohistochemical analysis and pathogenetic considerations.

Screening for expression of amelogenesis-related proteins represents a powerful molecular approach to characterize odontogenic tumors and investigate their pathogenesis. In this study, we have examined the presence and distribution of odontogenic ameloblast-associated protein (ODAM), amelotin (AMTN), ameloblastin (AMBN), and amelogenin (AMEL) by immunohistochemistry in samples of adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), developing odontoma, ameloblastoma, calcifying cystic odontogenic tumor (CCOT), ameloblastic fibroma (AF), myxoma, odontogenic fibroma (OF), and reduced enamel epithelia (REE). Positive results were obtained in those tumors with epithelial component, except for AF, OF, and ameloblastoma. ODAM was found around mineralized structures (dystrophic calcifications) and CEOT's amyloid, whereas AMTN stained the eosinophilic material of AOTs. The CCOT transitory cells to ghost cells were strongly positive with all proteins except AMEL, and the REE as well as odontomas showed immunoexpression for ODAM, AMTN, AMBN, and AMEL similar to those found in normal rat tooth germs. Based on these results, some histopathogenetic theories were formulated.

Fibronectin as an adjuvant in the diagnosis of oral inflammatory myofibroblastic tumor.

Inflammatory myofibroblastic tumor is a distinctive lesion composed of myofibroblastic spindle shaped cells accompanied by inflammatory infiltrate that may arise in various organs. It is believed to be a noneoplastic inflammatory condition, although this is still controversial. The recognition of inflammatory myofibroblastic tumor as an entity is important especially to avoid unnecessary surgery. A few cases have been reported in the oral cavity. This report primarily presents a case of inflammatory myofibroblastic tumor that arose in the floor of mouth of a 23-year-old woman. The proliferating spindle cells were immunoreactive for vimentin, smooth muscle actin, and muscle specific actin and negative for desmin, AE1/AE3, S-100, CD68, MyoD1 and caldesmon. In an attempt to assess the potential neoplastic nature of this lesion, immunohistochemical expression of ALK protein was performed, although no immunoreactivity was detected. Also, the presence of well differentiated myofibroblasts identified by fibronectin is discussed, as well as the importance in establishing an immunoprofile to better consolidate the diagnosis. We conclude that the study of fibronectin in case series may aid the diagnosis as well as the prediction of the tumor course.

A rare odontogenic cyst: Gingival cyst of the adult. A series of 20 new cases from a single center.

Gingival cyst of the adult (GCA) is a rare entity and comprises around 0.3% of all odontogenic cysts. Due to its rarity, there are a few retrospective studies on it. Therefore, the aim of this study was to present casuistic data of a 20-year retrospective study performed in a Brazilian oral pathology reference center. All cases diagnosed as gingival cyst of the adult in the last 20 years were retrieved from the files of the Oral Pathology Service. Data from the lesions and patients were tabulated and presented descriptively. From a total of 68,229 oral biopsies, 7,023 were odontogenic cysts, and among these only 20 cases were diagnosed as gingival cyst of the adult, resulting in the largest series of gingival cyst of the adult, from a single center, in the last 15 years. Most cases occurred in women, and although 53% affected the anterior mandible, 40% occurred in the anterior maxilla, which contrasts with the previous literature. Despite being a rare lesion GCA should be considered in the clinical differential diagnosis of gingival lesions presenting either in the maxilla or mandible.

Oral focal mucinosis of the hard palate and gingiva.

Oral focal mucinosis (OFM) is an uncommon, asymptomatic, submucosal, slow-growing nodule representing a counterpart of the cutaneous focal mucinosis (CFM). OFM has a female predilection with the highest prevalence in the fifth decade of life. About 68% of OFMs occur in the gingiva and 14% in the palate. We present the case of a 41-year-old woman presenting a progressively growing mass on the palate, since the last 8 months. The diagnostic workup led to the diagnosis of an unusual OFM with the clinical presentation involving the gingiva and hard palate. This case report discusses the clinical and histopathological differential diagnosis.

Kallikrein 4 and matrix metalloproteinase-20 immunoexpression in malignant, benign and infiltrative odontogenic tumors.

CONTEXT: Matrix metalloproteinase-20 (MMP20) (enamelysin) and kallikrein 4 (KLK4) are enzymes secreted by ameloblasts that play an important role in enamel matrix degradation during amelogenesis. However, studies have shown that neoplastic cells can produce such enzymes, which may affect the tumor infiltrative and metastatic behaviors. AIMS: The aim of this study is to assess the biological role of MMP20 and KLK4 in odontogenic tumors. MATERIALS AND METHODS: The enzymes were analyzed immunohistochemically in ameloblastoma, adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor, keratocystic odontogenic tumor with or without recurrence and odontogenic carcinoma. STATISTICAL ANALYSIS USED: Clinicopathological parameters were statistically correlated with protein expression using the Fisher's exact test. Kruskal-Wallis and Wilcoxon-independent methods were used to evaluate the differences in median values. RESULTS: Positive Immunoexpression was detected in all benign lesions, with a prevalence of 75-100% immunolabeled cells. Patients were predominantly young, Caucasian, female, with slow-growing tumors located in the mandible causing asymptomatic swelling. No KLK4 expression was seen in carcinomas, and the amount of MMP20-positive cells varied between 20% and 80%. Rapid evolution, recurrence and age >60 years characterized the malignant nature of these lesions. CONCLUSIONS: Data showed that KLK4 and MMP20 enzymes may not be crucial to tumoral infiltrative capacity, especially in malignant tumors, considering the diversity and peculiarity of these lesions. The significant immunoexpression in benign lesions, remarkably in AOT, is likely associated with differentiated tumor cells that can produce and degrade enamel matrix-like substances. This would be expected since the histogenesis of odontogenic tumors commonly comes from epithelium that recently performed a secretory activity in tooth formation.

In Situ Melanoma of the Gingiva Associated with Dense Inflammation and Pigment Deposition: A Potential Diagnostic Pitfall in Evaluating Stromal Invasion.

Melanoma is a highly aggressive neoplasm in which the neoplastic cells display melanocytic differentiation. Less than 1 % of all melanomas arise in the mucosal surfaces of the oral cavity, with purely in situ lesions being exceedingly rare tumors, but with a favorable prognosis compared with invasive lesions. We describe the clinical, histopathological and immunohistochemical findings in an uncommon case of in situ mucosal melanoma of the oral cavity with intense tumor-associated pigment deposition and inflammation complicating the morphological assessment of infiltrative areas.

Peripheral ameloblastoma with dystrophic calcification: an unusual feature in non-calcifying odontogenic tumors.

Peripheral ameloblastoma is a rare extraosseous counterpart of central ameloblastoma that occurs in soft tissues and may cause bone crest resorption. This study reports a peripheral ameloblastoma on the buccal gingiva of a 56-year-old man, which presented extensive squamous metaplasia areas, keratinization and dystrophic calcifications in the neoplastic islands. It is emphasized the need of a detailed imaging study and a long follow-up period to exclude bone involvement whenever peripheral ameloblastoma diagnosis is considered.

Clear cell odontogenic carcinoma: case report with immunohistochemical findings adding support to the challenging diagnosis.

Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic tumor associated with aggressive clinical behavior, metastasis, and low survival. We report a case of CCOC affecting the mandible of a 39-year-old man. The tumor presented a biphasic pattern composed of clear cell nests intermingled with eosinophilic cells and separated by collagenous stroma. Immunoreactivity to cytokeratin (CK), specifically AE1/AE3 and CK 8, 14, 18, and 19 was found, as well as to epithelial membrane antigen (EMA). The tumor cells were negative for S100 protein, CK 13, vimentin, smooth muscle actin, laminin and type IV collagen. Low labeling indices for the proliferation markers Ki-67 and proliferating cell nuclear antigen and to p53 protein might predict a favorable prognosis for the lesion. A surgical resection was performed, followed by adjuvant radiotherapy. A 2-year follow-up has shown no signs of recurrence. The significance of histochemical and immunohistochemical resources in the correct diagnosis of CCOC is analyzed.