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Objectives: The aim of this study was to analyze the immunohistochemical expression of fatty acid synthase (FASN) and cyclooxygenase-2 (COX-2) in tooth germ (TG), ameloblastoma (AM), ameloblastic carcinoma (AC), ameloblastic fibroma (AF), and ameloblastic fibrosarcoma (AFS).Study Design: Immunohistochemistry for FASN and COX-2 was performed in 10 TG, 44 AM, 10 AC, 9 AF, and 5 AFS specimens. The results were analyzed by using the immunoreactive score (IRS) and Kruskal-Wallis test followed by Dunn's post-test.Results: Most TG specimens were strongly positive for FASN, whereas COX-2 was weak or negative. All AM and AC specimens expressed both proteins. In AF specimens, FASN and COX-2 were variably expressed in the epithelium and negative in the mesenchyme. In AFS specimens, FASN was strongly positive in the malignant mesenchyme and variable in the epithelium; COX-2 was focal or weak in both components. FASN expression showed significant differences in the following comparisons: TG vs AC, AM vs AC, and AF vs AFS. Differences in COX-2 were significant when comparing TG specimens with AM, AC, and AF specimens.Conclusions: The results suggest that FASN and COX-2 overexpression may have a role in the pathogenesis of AM and AC, whereas in AFS, FASN seems to be mainly involved. Further studies are necessary to clarify these mechanisms and their clinical implications. [ABSTRACT FROM AUTHOR]

Objective: Our objective was to describe the clinicopathologic and immunohistochemical features of acute lymphoblastic leukemia/lymphoma (ALL/LBL) of the oral and maxillofacial region (OMF).Study Design: Cases diagnosed as ALL/LBL of the OMF region were retrieved from the files of 2 Brazilian and 1 Guatemalan oral pathology services from 2005 to 2017. Microscopic and immunohistochemical features of each case were reviewed and fully described, and clinical data were retrieved from the pathology reports.Results: During the period considered, 6 cases were identified. Male patients were the most affected (4:2), with a mean age of 19 years old. The mandible was involved in 2 cases, the maxilla in 2, the cheek mucosa in 1, and the parotid gland in 1. Painful swelling was the most common presentation, and 3 patients also had systemic complaints. Microscopically, tumors revealed solid infiltrations of small to medium-sized immature cells. "Puzzle-like" and "starry-sky" patterns were observed, and "single lane" growth was also identified. Immunohistochemically, 2 cases were diagnosed as T-cell ALL/LBL with the leukocyte common antigen (LCA)+/cCD3+/CD79 a+focal/CD20-/PAX5-/CD99+/CD34-/CD10+/terminal deoxynucleotidyl transferase (TdT)+ phenotype and 4 as B-cell ALL/LBL with the LCA+/CD3-/CD20-/CD79 a+/CD10+/CD34 variable/TdT+ predominant phenotype. The Ki67 index ranged from 80% to 99%.Conclusion: OMF ALL/LBL is rare, but its microscopic features and immunohistochemical profiles CD3+or CD79 a+/CD10+/CD34+variable/CD99+/TdT+ contribute to the correct diagnosis. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate hMutS proteins in developing human tooth, ameloblastomas, and ameloblastic carcinoma and to determine whether the expression of these proteins has any prognostic potential.Study Design: Ten cases of developing human tooth, 39 ameloblastomas, and 2 ameloblastic carcinomas were used to determine the distribution of the proteins during the process of carcinogenesis. Simultaneously, another sample of 73 ameloblastomas was arranged in tissue microarray, and their clinical, microscopic, and radiographic features; treatment outcome; presence of BRAF-V600E mutation; and follow-up data were assessed to determine the prognostic relevance of the expression of hMutS (hMSH2, hMSH3, hMSH6) and Ki-67. hMSH2 and hMSH6 were significantly downexpressed in ameloblastomas (P = .0059) compared with developing human tooth (P < .0001).Results: hMSH2, hMSH3 expression were significantly associated with BRAF-V600E mutation (P < .05). Simultaneous overexpression of hMutS was associated with recurrence (P = .035); however, these did not predict the disease-free survival of patients (P > .05).Conclusions: hMutS proteins are downregulated in ameloblastoma; moreover, simultaneous overexpression of these proteins in ameloblastoma was associated with recurrence but did not predict disease-free survival. [ABSTRACT FROM AUTHOR]

Analyze for the first time the immunohistochemical expression in tooth germ (TG) ameloblastoma (AM), ameloblastic carcinoma (AC), ameloblastic fibroma (AF) and ameloblastic fibrosarcoma (AFS) of fatty acid synthase (fasn) and cyclooxygenase (cox-2), which are highly associated to tumorigenic events and poor prognosis in several types of cancer and also are promising chemotherapy targets. Immunohistochemistry for fasn and cox-2 was performed in 10 TG, 44 solid or conventional AM, 10 AC, 9 AF, and 5 AFS. Results were analyzed using the Immunoreactive Score (IRS). Most TG were strongly positive for fasn and negative or weakly positive for cox-2. All AM and AC expressed fasn and cox-2. AC showed higher expression of both markers. In AF, fasn and cox-2 were variably expressed in epithelium and negative in the mesenchyme, while in AFS, the mesenchymal malignant component was strongly positive for fasn , whereas cox-2 was negative in both components. The coexpression of fasn and cox-2 may be involved in the pathogenesis and behavior of AM and AC, while in AFS only fasn seems to play a role in the sarcomatous component. These markers could be a potential therapeutic target in the future; however, further studies are necessary. [ABSTRACT FROM AUTHOR]

A 67-year-old male farmer presented with the complaint of a slightly symptomatic spot in the mouth for the past 2 years. The medical history discussed no abnormalities. Extraoral examination revealed cervical lymphadenopathy on the left side and intraoral examination a blue-black sessile elevated mass with irregular borders, involving the attached vestibular gingiva of teeth 27 and 28, extending to the hard palate and measuring approximately 3.5 cm. Panoramic radiograph did not show bone involvement. A diagnostic hypothesis of oral melanoma was made, and an incisional biopsy was performed. Microscopic findings revealed a proliferation of densely pigmented pleomorphic cells, invading the subepithelial connective tissue in sheets or nests in an organoid fashion. Immunopositivity for S-100, Melan A, and HMB-45 confirmed the diagnosis of melanoma. The patient was referred to an oncology hospital, and, unfortunately, we have no information if he initiated the treatment. Financial Support: CAPES. [ABSTRACT FROM AUTHOR]