Lipomatous lesions of the parotid gland.

PURPOSE: Lipomatous lesions of the parotid gland are rare and seldom considered in the initial diagnosis of a parotid mass. We report our experience in the management of patients with lipomatous lesions affecting the parotid gland. PATIENTS AND METHODS: Retrospective analysis of all parotidectomies performed for neoplastic lesions in the maxillofacial unit between 1975 and 2003 and patients with lipomatous lesions involving the parotid gland were identified; 638 parotidectomies were performed in this period on 629 patients in which 660 neoplasms were identified. Eight patients were found to have lipomatous lesions and form the basis of this study. RESULTS: Lipomatous lesions accounted for only 1.3% of parotid tumors and occurred more frequently in males, at a ratio of 3 to 1. The most common presentation was that of a slowly enlarging, painless mass. Computed tomography scan was the most frequent imaging modality undertaken, and in 3 patients a diagnosis of a lipoma was made preoperatively. Seven patients underwent a superficial parotidectomy and 1 patient had a total conservative parotidectomy because of the deep lobe location of the mass. Five patients were found to have a focal lipoma and 3 patients had diffuse lipomatosis. There were no recurrences. Temporary facial nerve palsy and Frey's syndrome were the most frequent complications. CONCLUSION: Lipomatous lesions accounted for only 1.3% of all parotid tumors. There were no specific distinguishing clinical features in our patients, and an accurate preoperative diagnosis was made in 3 patients based on imaging investigations. A well-circumscribed lipoma was more common than diffuse lipomatosis. Superficial parotidectomy was the treatment of choice and there were no recurrences in our series.

Expression of type 2 nitric oxide synthase and vascular endothelial growth factor in oral dysplasia.

PURPOSE: The small molecule nitric oxide (NO), produced by a family of enzymes called NO synthase (NOS), has a diverse array of functions in both physiologic and pathologic states. Prolonged production of NO by the isoform NOS2 has been implicated in human cancer progression. NO has an important role in angiogenesis, being both an upstream signal and a downstream effector molecule to vascular endothelial growth factor (VEGF). The latter group of proteins are crucial for vascular endothelial cell proliferation and permeability. The expression of VEGF increases with cancer progression. Because angiogenesis is a prerequisite for the development of invasive cancer, this immunohistochemical study investigated the expression of NOS2 and VEGF in oral epithelial dysplasia. MATERIALS AND METHODS: An immunohistochemical study was performed using monoclonal antibodies to NOS2 and VEGF on archival formalin-fixed, paraffin-embedded tissue of 33 cases of oral dysplasia. RESULTS: A significant correlation was found between NOS2 and VEGF expression in oral dysplasia (P <.001). Expression of both NOS2 and VEGF also correlated with the severity of dysplasia (P <.001, P <.002). CONCLUSIONS: These findings may provide further understanding to the complex transformation of oral epithelial dysplasia to invasive carcinoma and the role of angiogenesis in this process.