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.

The present study aimed to detect possible differences in the data of oral squamous cell carcinomas (OSCC) cases diagnosed in a Dental School in São Paulo city over the last 40 years. The records of patients diagnosed as having OSCC between the years 1960 and 2008 were retrieved. The whole period was divided into four time periods. A total of 1,564 cases were reviewed. The variables analyzed were: sex, age, race, anatomical site, lesion duration, and lesion size. The chi-square test was used for statistical analysis. Overall, males were more affected than females (3:1), but when comparing the first and last time periods, the ratio decreased significantly (5.8:1 to 2.8:1). A significant increase in the rate of OSCC in patients over 80 years was observed in the last time periods. The gingiva was the most affected site, but the frequency of lower lip involvement increased in the last time period. Regarding lesion size and duration of symptoms at the time of diagnosis, there was a significant difference between the first and last time periods. Smaller lesions were found and the time of lesion development was shorter in the last few years of the study. These findings support the optimistic view that, in recent years, earlier diagnosis has resulted from early oral cancer detection in São Paulo city.

Lichen planus (LP) is a mucocutaneous disease with well-established clinical and microscopic features. The oral mucosa and skin may present clinical and microscopic alterations similar to those observed in LP, called lichenoid reactions (LRs), which are triggered by systemic or topical etiological agents. The difficulties faced to establish the differential diagnosis between the two pathologies were investigated in the literature. It was observed that the etiology of LP is still under discussion, with a tendency to self-immunity, while the etiology of LRs is related to the contact with specific agents, such as metallic restorative materials, resins, and drugs, allowing the establishment of a cause-effect relationship. In this case, the disease is caused by the antigen fixation in the epithelial cells, which are destructed by the immune system. Based on these data, protocols are suggested for this differentiation. The important role played by the integration between the clinician and the oral pathologist in the diagnostic process is highlighted. The treatment of LP comprises mainly the utilization of corticosteroids and the LR is treated by removal of the causal factor. Differentiation between the two diseases allows an effective and correct therapeutic approach.

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The different types of nerve sheath cells observed in the present series reinforce the presence of heterogeneous population in NFs. The strong positivity for S-100 suggests that the lesions were more composed by S-100-positive Schwann cells than other cells. Besides, the high number of CD34-positive cells suggests that this marker can be useful for the differential diagnosis of NFs against PEN, traumatic neuromas and Schwannomas. Finally, the low immunostaining for p53 and Ki-67 may indicate that NFs massively composed by S-100-positive Schwann cells present low potential of aggressiveness and malignant transformation.