Immunohistochemical study of GLUT-1 in oral peripheral nerve sheath tumors.

AIM: To investigate the immunoexpression and diagnostic applicability of human erythrocyte-type glucose transporter protein (GLUT-1) in oral peripheral nerve sheath tumors. MATERIAL AND METHODS: Specimens diagnosed as oral peripheral nerve sheath tumors archived in the Oral Pathology Service of Universidade Federal de Minas Gerais from 1966 to 2006 were evaluated. Thirty-four lesions were included: 15 traumatic neuromas, 11 neurofibromas, four neurilemmomas, and four malignant peripheral nerve sheath tumors (MPNST). One case of neurofibroma was associated with neurofibromatosis type I. Immunohistochemistry for S-100 and GLUT-1 was performed. S-100 was immunopositive in all lesions. RESULTS: Benign lesions were immunopositive for GLUT-1 except in two (18.2%) cases of neurofibromas. In the traumatic neuroma, the perineuriums were immunopositive for GLUT-1. In the neurofibroma, the immunoreactivity was heterogeneous. Immunopositivity was observed at levels of 54.5% in the periphery of the lesion, 9.1% in the center, and 18.2% in both. The neurilemmoma demonstrated immunopositivity in the capsule. One case (25%) of MPNST presented GLUT-1 positive stain in occasional cells distributed homogeneously in all the tumor area. CONCLUSION: GLUT-1 is a useful marker for perineurial cells and should be included in the oral peripheral nerve sheath tumors immunophenotyping thus aiding in the correct diagnosis of these lesions.

Inflammatory myofibroblastic tumor of the alveolar mucosa of the mandible.

Inflammatory myofibroblastic tumor is a rare lesion composed of myofibroblastic spindle cells accompanied by inflammatory infiltrate. The objective of this paper is to report an uncommon case of inflammatory myofibroblastic tumor located in the alveolar mucosa of the mandible. A 33-year-old male presented an asymptomatic tumoral lesion, firm, pedunculated, pink-colored, covered by smooth mucosa, with focal ulceration, measuring 30x20x20 mm, located in the left posterior alveolar mucosa. Clinical diagnosis was soft tissue tumor. An excisional biopsy was made. Microscopic examination showed compact fascicular spindle cells proliferation with a diffuse inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils. Large ganglion-like cells were observed. The lesional cells were immunopos-itive to vimentin, a-smooth muscle actin, muscle specific actin, and CD68. Negative immunostain was observed to S-100, Bcl-2, Ki-67, desmin, CD34, and cytokeratin. A diagnosis of inflammatory myofibroblastic tumor was performed. After 28 months of follow-up there was no recurrence. Although no evidence of oral inflammatory myofibroblastic tumor recurrence or malignant transformation has been reported, it has been observed that in inflammatory myofibroblastic tumor of other regions a prolonged follow-up is necessary after surgical excision.

Retrospective analysis of peripheral odontogenic fibroma (WHO-type) in Brazilians.

AIM: The purpose of this study is to present data on a series of peripheral odontogenic fibroma, WHO (World Health Organization)-type (POF), in Brazilians and to compare the results with previously reported studies. METHODS: The study sample was made from the number of POF cases and its synonymies diagnosed from 1950 to 2004 at the Oral Pathology Service of the Federal University of Minas Gerais. The cases were reviewed in hematoxylin-eosin stain and the histological features were evaluated in accordance with the classification WHO. Patient's data about gender, age and race and the lesion's clinical data were obtained from the biopsy request forms, after the definite diagnosis of POF. RESULTS: Seventeen diagnoses of POF were found. Data showed that POF has a higher prevalence in females (88.2%), occurring in the second and fourth decades of life (29.4% each), and in Caucasians (64.7%). The most common location was the posterior region of the mandible (41.1%). It was an asymptomatic lesion (23.5%) with an average size of 1.1 to 2.0 cm (35.2%). The histological findings were: 1) fibroblastic tissue high cellularity (58.8%); 2) scarce odontogenic epithelium (64.7%); 3) inflammation (94.1%) and 4) absence of calcification (58.8%). CONCLUSIONS: Clinical and histological data of POF in Brazilians showed important characteristcs for its diagnosis. This epidemiological data will generate a substantial contribution to the clinical, histological diagnosis and behavior of this lesion.

Expression levels of the receptor activator of NF-κB ligand and osteoprotegerin and the number of gram-negative bacteria in symptomatic and asymptomatic periapical lesions.

OBJECTIVE: The study aimed to verify the potential correlation between the detected amount of gram-negative bacteria and the radiographic sizes of the lesions in patients with symptomatic and asymptomatic apical periodontitis. Furthermore, to evaluate whether the expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) and the RANKL/OPG ratio are differentially regulated in both groups. DESIGN: Twenty patients with periapical lesions were divided into two groups: symptomatic (SYM) n=10 and asymptomatic (ASYM) n=10. After periapical surgery, the lesions were collected and processed for histological examination, and immunohistochemistry. The percentage of RANKL- and OPG-immunopositive areas relative to the total area of the microscopic field was calculated. For gram staining, the number of gram-negative cells per microscopic field was assessed. The radiographs of each patient were processed and measured. The Student's t-test and the Pearson correlation coefficient were performed. RESULTS: The SYM group showed a significantly higher number of gram-negative cells (p=0.007) when compared to the ASYM group. A higher number of gram-negative bacteria occurred more frequently in larger periapical lesions and the SYM group (p=0.03). The expression for RANKL and OPG and the RANKL/OPG ratio were not significantly different between the groups. There was a significant positive correlation between the number of bacteria and OPG levels in the SYM group (p=0.01). CONCLUSION: The number of bacteria seems to influence the symptoms and the radiographic size of a periapical lesion. Gram-negative bacteria may play an important role in OPG activity in the SYM group.

GLUT-1 in oral benign vascular lesions.

AIM: To investigate the accuracy of histological diagnosis of oral hemangioma, oral vascular malformation and oral pyogenic granuloma according to immunohistochemical evaluation of the human erythrocyte-type glucose transporter protein (GLUT-1), and to observe the immunoexpression of this protein in oral varix. MATERIALS AND METHODS: Immunohistochemistry for GLUT-1 was performed in 93 histologically diagnosed cases of oral benign vascular lesions: 17 vascular malformations, 19 hemangiomas, nine varix, and 48 pyogenic granulomas. Descriptive analyses were performed. RESULTS: None of the cases of the oral benign vascular lesions evaluated were immunopositive to GLUT-1. The 19 cases histologically diagnosed as oral hemangioma that showed negative staining to GLUT-1 were reclassified as oral pyogenic granuloma or oral vascular malformations. The histological evaluation itself is not enough to obtain the correct diagnosis of oral HEM as none of the sample cases were true hemangioma. All sample cases with initial vascular malformation or pyogenic granulomas classification were negative to GLUT-1, demonstrating the accuracy of histological diagnosis of these lesions itself. Oral varix showed negative staining to GLUT-1 in blood vessels. CONCLUSIONS: GLUT-1 is an useful, effective and important auxiliary marker for the diagnosis of oral benign vascular lesions. CLINICAL RELEVANCE: This study showed that histological diagnosis alone is not sufficient to correct diagnoses of oral hemangioma. Moreover, immunohistochemistry to GLUT-1 is a useful and easy diagnostic method that may be used to avoid such misdiagnosis. Accurate diagnosis of these oral lesions has an important clinical relevance allowing: (1) correct management, (2) adequate communication among the multidisciplinary team (dentist, dermatologist, pediatrist, radiologist, pathologist, and surgeon), (3) understanding of the biological behavior of the lesions, and (4) facilitate the development of new therapeutic modalities. Thus, supporting the use of this marker in medical and dentistry communities is warranted.