BRAF p.V600E status in epithelial areas of ameloblastoma with different histological aspects: Implications to the clinical practice.

BACKGROUND: BRAF p.V600E is reported in up to 80% of ameloblastomas. Despite the high frequency, the presence of this mutation in different histopathological areas of the tumour has not been investigated. This information has an important role in the use of BRAF p.V600E assessment as an auxiliary tool in the differential diagnosis between unicystic ameloblastoma and other odontogenic cystic lesions, especially when only incisional biopsies are available. Therefore, the purpose of the present study was to investigate BRAF p.V600E heterogeneity in unicystic ameloblastoma. METHODS: Five cases of ameloblastoma and two dentigerous cysts were analysed. The regions exhibiting different microscopic characteristics were selected from each ameloblastoma case and manually dissected. TaqMan allele-specific qPCR or Sanger sequencing was performed to determine BRAF p.V600E status. RESULTS: We screened the mutation in a small cohort of UA and no molecular heterogeneity was found. Four cases of ameloblastoma (80%) exhibited BRAF p.V600E in all different areas evaluated. One case did not harbour the mutation in any microscopic region analysed. The BRAF mutation was absent in the dentigerous cysts. CONCLUSION: Ameloblastomas appear to exhibit a homogeneous profile regarding the BRAF p.V600E no matter what histological feature is observed under light microscopy, suggesting that this molecular test may contribute to establish the correct diagnosis in cases microscopically resembling other odontogenic lesions.

Preventing bisphosphonate induced osteonecrosis of the jaw with a polyguanidine conjugate (GuaDex): A promising new approach.

Osteonecrosis of the jaw (ONJ) is a relatively rare side effect after prolonged use of bisphosphonates, which are drugs used to treat bone resorption in osteoporosis and certain cancers. This study introduces a novel ONJ model in rats by combining exposure to bisphosphonates, oral surgery, and bacterial inoculation. Potential ONJ preventive effects of polyguanidine (GuaDex) or antibiotics were evaluated. The study consisted of twenty-four male Wistar rats were divided into four groups. Groups 1 to 3 were given weekly doses of i.v. Zoledronic acid (ZA), four weeks before and two weeks after an osteotomy procedure on their left mandibular first molar. Group 4 was a negative control. Streptococcus gordonii bacteria were introduced into the osteotomy pulp chamber and via the food for seven days. On day eight, the rats were given different treatments. Group 1 was given a GuaDex injection into the osteotomy socket, Group 2 was given an intramuscular (i.m.) injection of clindamycin, Group 3 (positive control) was given an i.m. injection of saline, and Group 4 was given an i.m. injection of saline. Blood samples were taken two weeks after the osteotomy procedure, after which the rats were euthanized. Bone healing, bone mineral density, histology, and blood status were analyzed. The results showed that Group 1 (GuaDex) had no ONJ, extensive ongoing bone regeneration, active healing activity, vascularization, and no presence of bacteria. Group 2 (clindamycin) showed early stages of ONJ, avascular areas, and bacteria. Group 3 showed stages of ONJ, inflammatory infiltrates, defective healing, and bacterial presence, and Group 4 had normal healing activity and no bacterial presence. Conclusion: ZA treatment and bacterial inoculation after tooth extraction inhibited bone remodeling/healing and induced ONJ characteristic lesions in the rats. Only GuaDex apparently prevented ONJ development, stimulated bone remodeling, and provided an antimicrobial effect.

Diffuse cutaneous leishmaniasis with oral involvement in a patient of Northern Mexico.

Diffuse cutaneous leishmaniasis is a rare chronic infectious disease, associated with Leishmania mexicana and L. amazonensis, presenting as multiple non-ulcerative painless nodules, with a tendency to relapse soon after treatment. We report a case of a 56-year-old Mexican woman exhibiting nodular lesions, plaques, crusts and scars involving the whole body. A solitary nodule was present at the junction between hard and soft palates. Diffuse cutaneous leishmaniasis is a disfiguring disease resulting in severe scarring if untreated.

Calcifying Odontogenic Cyst Associated With Dentigerous Cyst in a 15-Year-Old Girl.

Calcifying odontogenic cyst (COC) is a rare odontogenic cyst with ameloblastic epithelial lining containing clusters of ghost cells. COCs have been described in association with several odontogenic tumors, more commonly odontomas and rarely with dentigerous cyst (DC). In this article, we describe a case of COC associated with DC in a 15-year-old girl, who presented with a swelling on the right middle third of the face, producing facial asymmetry. Panoramic radiography showed a well-circumscribed, corticated, and unilocular radiolucency at the level of the right maxillary sinus, involving 2 unerupted premolars. The lesion was enucleated and histologically revealed a COC associated with DC, which presented mucous metaplasia. Immunohistochemical reactions were performed to better illustrate this rare synchronous occurrence of COC and DC, showing positivity for CK5, CK14, CK19, and p63 in both lesions. CK18 was negative in COC, and Bcl-2 was negative in DC. Periodic acid Schiff highlighted the mucous cells in the DC lining.

Hyperpigmentation of hard palate induced by chloroquine therapy.

The antimalarials are one of the most commonly prescribed drugs for conditions such as lupus erythematosus and rheumatoid arthritis, and the side effects, though infrequent, are well known. The antimalarial agent chloroquine diphosphate usually causes pigmentary changes in the oral mucosa characterized by a bluish-grey to black discolorations mainly in the hard palate. Considering only the hard palate hyperpigmentation caused by chloroquine, to the best of our knowledge, only 13 cases have been reported in the English language literature. We described an additional case of palate hyperpigmentation related to the chronic use of chloroquine diphosphate in a 60-year-old Mexican woman. Although the diagnosis is usually made based on medication history and clinical presentation, a biopsy specimen may be helpful to confirm the diagnosis. Clinicians must be aware of these drugs and their adverse effects in order to make the correct diagnosis and decide on the optimal treatment for the condition. Key words:Oral cavity, hard palate, hyperpigmentation, chloroquine, antimalarials.

Intraoral EBV-positive sporadic Burkitt lymphoma in an elderly patient with bilateral presentation

Sporadic Burkitt lymphoma (SBL) is a variant of Burkitt lymphoma that occurs worldwide, affecting mainly children and young adults. Association with Epstein-Barr virus (EBV) can be identified in approximately 20-30% of cases. Herein we described a case of a 63-year-old male presenting intraoral bilateral mandibular swelling, subjacent to fixed dental prosthesis, with one month of duration. Incisional biopsies were performed, and after two days, the patient was hospitalized due to malaise and breathing difficulty, and died after a week when an abdominal tumor was detected. The mandibular biopsies revealed a diffuse proliferation of medium-sized monomorphic atypical lymphoid cells exhibiting numerous mitoses and areas of "starry-sky" pattern. The tumor showed immunohistochemical positivity for CD20, CD10, Bcl-6, and Ki-67 (≈ 100%); it was negative for CD3, Bcl-2, Vs38c, and MUM-1. Positivity for EBV was found by in situ hybridization. The final diagnosis was intraoral SBL positive for EBV. Clinical, morphological and molecular criteria are necessary for the correct diagnosis of aggressive B-cell neoplasms positive for EBV in elderly patients.

Melatonin: bone metabolism in oral cavity.

Throughout life, bone tissue undergoes a continuous process of resorption and formation. Melatonin, with its antioxidant properties and its ability to detoxify free radicals, as suggested by Conconi et al. (2000) may interfere in the osteoclast function and thereby inhibit bone resorption, as suggested by Schroeder et al. (1981). Inhibition of bone resorption may be enhanced by a reaction of indoleamine in osteoclastogenesis. That it has been observed melatonin, at pharmacological doses, decrease bone mass resorption by suppressing through down regulation of the RANK-L, as suggested by Penarrocha Diago et al. (2005) and Steflik et al. (1994). These data point an osteogenic effect towards that may be of melatonin of clinical importance, as it could be used as a therapeutic agent in situations in which would be advantageous bone formation, such as in the treatment of fractures or osteoporosis or their use as, a bioactive surface on implant as suggested by Lissoni et al. (1991).