The neurofibroma occurs as isolated or multiple lesions frequently associated with neurofibromatosis type 1 (NF-1). The aim of this study was to analyze the clinical and histopathological features of neurofibromas, particularly the plexiform variant, in the skin and oral mucosa, discussing their pathogenesis as well as clinical management of isolated lesion unassociated with NF1. The clinicopathologic features of 66 neurofibromas in the head and neck region diagnosed at the pathology laboratories of the Bauru Dentistry School and Lauro de Souza Lima Research Institute from 1970 to 2003 were reviewed. The clinical data, therapy, and follow-up information were obtained from the medical records. The results showed a high frequency of cutaneous lesions (81.8%) occurring mainly in females older than 40 years. Isolated neurofibromas were found in 51.2% of patients, and multiple lesions were often associated with the NF-1. The histopathological analysis demonstrated that diffused neurofibromas occur more frequently than the plexiform type. However, one case of plexiform neurofibroma was detected in the oral mucosa as an isolated lesion non-associated with the NF-1. The indolent clinical behavior of isolated neurofibromas in the head and neck region and the absence of NF-1 association reinforce that sporadic lesion could be hyperplastic or hamartomatous rather than neoplastic in nature.

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Osteoporosis is commonly associated with estrogen deficiency. However, the mechanisms by which the lack of this hormone causes bone loss are poorly understood. The bone structure of the oral cavity seems to be affected by estrogen deficiency, since a delayed healing process after tooth extraction has been observed after ovariectomy in rats. The aim of this study was to describe the effect of the absence of estrogen on the expression and activity of matrix metalloproteinases (MMC)-2 and -9 and expression of types I and III collagens in the alveolar granulation tissue of young female rats after tooth extraction. Sixty-six, four-week-old female rats underwent bilateral ovariectomies (OVX) or sham operations. Three weeks later, both first and second mandibular molars were extracted and the animals were killed by cervical dislocation 3, 5, or 7 days after tooth extraction. The granulation tissues were collected from the extracted alveolar sockets and used for zymographic, Western blot, or reverse transcription polymerase chain reaction (RT-PCR) analysis. There was a gradual increase on the expression of all studied proteins as well as MMP-2 and -9 activities in the periods after surgery. In contrast, OVX animals showed a significant decrease in the gelatinolytic activities and expression of MMP-2 and -9 and types I and III collagens. The results presented here in suggest that the absence of estrogen may possibly contribute to the delayed alveolar wound healing by interfering with the extracellular matrix turnover.