Ultrastructural features of monomorphic adenoma of the parotid gland.

A monomorphic adenoma of the parotid gland (basaloid type) was studied with the electron microscope. In general, the tumor consisted of a single cell type, except in areas of squamous metaplasia. The cells were polygonal with prominent nuclei and scant cytoplasmic organelles. Intercellular junctions and plasmalemmal projections (filopodia) were conspicuous. Myoepithelial cells and secretory granules were absent. On the basis of these ultrastructural features, it is proposed that the interlobular duct, rather than the intercalated duct, is the probable site of origin of this tumor.     

Angiolithiasis in the parotid gland.

Angiolithiasis in salivary glands is a very rare finding, and the knowledge of the morphology and histogenesis of these stone formations is therefore limited. Six small angioliths from the left parotid gland of a 19-year-old girl were examined histologically, microradiographically and diffractometrically. The angiolithiasis developed from a regressed hemangioma which had been observed since the patient was 3--4 years old. The angioliths, which were encapsulated, exhibited in some areas diffuse laminations with shells of alternatingly high and low mineral content. In other areas, however, the sturcture of the stones was rather homogeneous. The central part of all angioliths was highly mineralized. All the examined specimens exhibited a mineral pattern of pure apatite. Due to presence of erythrocytes as well as of fibroblasts in the matrix of the examined noduli, the diagnosis of angiolithiasis was established.     

Sialolipoma of the parotid gland.

A case of slow-enlarging mass of the parotid region in a 44-year-old male is presented, which proved to be a lipomatous tumour of the parotid gland. The clinical impression was that of a benign salivary gland tumour. The tumour was situated in the deep lobe of the gland, thus a total parotidectomy was performed, with preservation of the facial nerve. Microscopically the lesion was described as consisting of mature adipose tissue, which, however, encompassed both glandular elements and nerve bundles within it. This tumour has been recently recognized as a separate entity under the term 'sialolipoma'.     

Haemangiomas of the parotid gland in children.

The authors present the case histories of 40 intraparotid haemangiomas, in 11 of which they achieved healing after radical surgical treatment (parotidectomy). Since 1971, the authors have adopted a conservative approach (not surgical), seeing that most of the cases involute spontaneously up to complete healing. None of the 29 cases treated conservatively has undergone exacerbations of the process, after the age of 6-9 months. No emergency surgical operations were required.     

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.     

Inhibition of synthesis of rat parotid secretory proteoglycan in a gland slice system.

The chondroitin sulphate contained within the secretory granules of the rat parotid gland and its saliva was shown to be in the form of a proteoglycan by using inhibitors of proteoglycan synthesis in a gland slice system. Gland slices were incubated in either p-nitrophenyl-beta-D-xyloside or chlorate in the presence of both [3H]-leucine and [35S]-sulphate. The slices were next homogenized and either the 250 g supernatant fraction (for initial experiments) or secretory granule-containing fractions were isolated. Protein and proteoglycans of these fractions were precipitated in 10% trichloracetic acid (TCA), and glycosaminoglycans in cetylpyridinium chloride. [3H]-leucine and [35S]-sulphate were quantitated in each type of precipitate by scintillation counting. The results showed that 1 mM xyloside had no effect on protein or glycosaminoglycan synthesis but blocked incorporation of radiosulphate into TCA-precipitable material. Sixteen mM chlorate almost totally inhibited incorporation of radiosulphate into glycosaminoglycan and TCA-precipitable material. These findings demonstrate that the rat parotid secretory chondroitin sulphate is indeed a proteoglycan because its synthesis is blocked by the protein-core analogue acceptor, p-nitrophenyl-beta-D-xyloside. This system offers opportunities for exploring the functional role of chondroitin sulphate proteoglycan in this salivary gland.     

The role of aryl hydrocarbon receptor (AhR) in the pathology of pleomorphic adenoma in parotid gland

ObjectivesPleomorphic adenoma (benign mixed tumor) is one of the most common salivary gland tumors. However, molecular mechanisms implicated in its development are not entirely defined. Therefore, the study aimed at definition of aryl hydrocarbon receptor (AhR) involvement in pleomorphic adenoma pathology, as the AhR controlled gene system was documented to play a role in development of various human tumors.DesignThe study was carried out in pleomorphic adenoma and control parotid gland tissues where gene expression of AHR, AhR nuclear translocator (ARNT), AhR repressor (AHRR), as well as AhR controlled genes: CYP1A1 and CYP1B1, at mRNA and protein (immunohistochemistry) levels were studied. Functional evaluation of AhR system was evaluated in HSY cells (human parotid gland adenocarcinoma cells) using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as AhR specific inducer.ResultsPleomorphic adenoma specimens showed cytoplasmic and nuclear AhR expression in epithelial cells as well as in mesenchymal cells. In parotid gland AhR was expressed in cytoplasm of duct cells. Quantitative expression at mRNA level showed significantly higher expression of AHR, ARNT and CYP1B1, and comparable levels of CYP1A1 in pleomorphic adenoma tissue in comparison to healthy parotid gland. The HSY cell study revealed significantly higher expression level of AHRR in HSY as compared with MCF-7 cells (human breast adenocarcinoma cell line used as reference). Upon TCDD stimulation a drop in AHRR level in HSY cells and an increase in MCF-7 cells were observed. The HSY and MCF-7 cell proliferation rate (measured by WST-1 test) was not affected by TCDD.ConclusionsSummarizing both in vitro and in vivo observations it can be stated that AhR system may play a role in the pathology of pleomorphic adenoma.     

174例腮腺肿瘤临床分析

目的:对腮腺肿瘤手术病例进行总结分析,以期达到提高治愈率,减少并发症的目的。方法:对174腮腺肿瘤病例治疗方法和预后作系统性回顾分析。结果:31例术后出现Frey综合症(17.8%),44例术中植入脱细胞异体真皮基质病例则无1例出现Frey综合症;18例出现暂时性面瘫(10%);10例发生涎瘘(6%);7例发生永久性面瘫(4%),139例良性肿瘤无1例出现术后复发,35例恶性肿瘤有15例出现原位灶复发或颈淋巴结转移。结论:腮腺良性肿瘤治疗应以局部切除及次全切除为首选治疗方式,恶性肿瘤应在全切除术的基础上行选择性颈淋巴清扫术,术中植入脱细胞异体真皮基质是预防Frey综合征的有效方法。     

Mucoepidermoid carcinoma in the parotid gland. A case report

Dental clinicians should be familiar with the modalities used in the clinical setting that can help to identify the presence of a tumor and to distinguish a benign from a malignant lesion. We present a case report to demonstrate the systematic approach and techniques used in the diagnosis of a malignant neoplasm, a mucoepidermoid carcinoma of the parotid gland. Ultimate diagnosis is determined by microscopic analysis of a surgical specimen.     

Recurrent pleomorphic adenoma of the parotid gland: role of neutron radiation therapy

ABSTRACT: Recurrent pleomorphic adenoma (RPA) of the parotid gland represents a challenging task for maxillofacial surgeons. The role of radiotherapy in the treatment of RPA of the parotid gland has been studied in previous experiences, and its use has been considered questionable. The aims of our article were to analyze and illustrate a case of RPA, initially treated with enucleations at another institution, showing a multinodular pattern with positivity for S-100 protein and cytokeratin, managed with conservative parotidectomy and neutron radiotherapy.     

The crystal chemistry of submandibular and parotid salivary gland stones.

The mineral composition of 38 human salivary gland stones was described qualitatively on the basis of X-ray diffraction and chemical analysis. In 32 submandibular stones, hydroxyapatite was the most frequently observed phase with a magnesium-substituted whitlockite co-phase (octacalcium phosphate was rarely present). In six parotid gland stones, apatite, magnesium substituted whitlockite and octacalcium phosphate were noted to be the major crystalline phases. Brushite was rarely found in either submandibular or parotid stones. This is the first report of octacalcium phosphate in salivary gland stones. All stones had ash weights ranging from 75--80%, but their Ca/P ratios could not be used to predict the crystalline phases present. Whitlockite was observed more frequently in the central regions of the submandibular stones than in the outer crusts. Possible explanations for the presence of each of these phases are discussed.     

Age-related changes in the cellular level of amylase and protein synthesis in the rat parotid gland

Age-related changes in the cellular content of secretory proteins and protein synthesis were studied in parotid glands of rats of various ages. The secretory protein content (determined by measuring the level of alpha-amylase activity) and the synthesis of proteins (assayed by the rate of incorporation of 3H-leucine into acid-insoluble proteins) decline with increasing age. Morphological and radioautographic studies of the gland indicate that the decline in protein synthesis is due to the reduction in the ability of secretory cells to synthesize proteins.     

Statistical study for sonographic differential diagnosis of tumorous lesions in the parotid gland.

OBJECTIVE: The purpose of this study was to clarify characteristic sonomorphologic features of parotid lesions statistically and to propose new criteria for the differential diagnosis. STUDY DESIGN: Eighty-six tumorous lesions were analyzed with regard to the following sonomorphologic features: boundary, shape, echo intensity level, distribution of internal echoes, and acoustic enhancement. Stepwise polychotomous logistic regression analysis was performed to assess characteristic sonographic features. As dependent variables, we used "pleomorphic adenoma," "Warthin tumor," "malignant tumors" and "other benign lesions"; as predictor variables, we used the aforementioned sonomorphologic features. Proportion of the occurrence of each dependent variable was calculated. RESULTS: Lobular shape and homogeneous internal echoes predicted pleomorphic adenoma. A lesion with multiple anechoic areas would be Warthin tumor with very high sensitivity. Malignant tumors showed either heterogeneous internal echoes without characteristic structures or polygonal shape. CONCLUSIONS: These sonomorphologic features should be observed to make more exact differential diagnoses for operation and therapy planning.