Therefore, an excisional biopsy is necessary for a prompt diagnosis and confirmation. The salivary glands are classified as major or minor. This is considered to be a function of the neoplastic myoepithelium, which shows histological and. The various types of salivary gland tumors are best distinguished by their histologic patterns. Histogenesis of salivary gland neoplasms dwivedi n, agarwal a. Salivary gland tumors sgts are rare neoplasms accounting for 0.
Still in the us, carcinomas of the major salivary glands comprise 11% of oropharyngeal neoplasms. It emphasizes the histogenesis and molecular pathogenesis of salivary gland tumors. Sox10 is a novel marker of acinus and intercalated duct. Salivary gland tumors are relatively uncommon and account for approximately 36% of all neoplasms of the head and neck.
Current classifications of salivary gland tumors separate mucoepidermoid carcinoma from other neoplasms on the basis of a number of histological features, in particular the lack of participation of neoplastic myoepithelial cells. According to this theory, warthins and oncocytic tumors are thought to arise from striated ductal cells, acinic cell tumors. Pdf histogenesis of salivary gland neoplasms shaleen. The morphological classification of salivary gland tumors is based upon the publications of the who 1 and the armed forces institute of pathology. Salivary gland neoplasms, arising in major or minor salivary and mucous glands, constitute a very heterogeneous group of tumours. A salivary gland neoplasm is an abnormal growth of the cells constituting the salivary glands. Salivary gland tumours tumours of salivary glands represent a complex and histopathologically diverse group of tumour diagnosis and management is complicated by the fact that they are in frequent making up only 1% of head and neck tumour. Wt1 expression in salivary gland pleomorphic adenomas. Certain reserve cells in the normal adult salivary gland are replicating population which are ultimately responsible for the tumour formation. Salivary gland tumours tumours of salivary glands represent a complex and histopathologically diverse group of tumour diagnosis and management is complicated by the fact that they are in frequent making up only 1% of head and neck tumour proper management require and accurate diagnosis by the pathologists and physicians. Her2 expression in salivary gland carcinomas clinical. The majority of these neoplasms are benign and only 20% are. Their complexity is attributed to heterogeneity of the cells of origin of these lesions.
The problem is compounded by the ability of these cells to differentiate. With respect to salivary gland pleomorphic adenomas, light microscopic and ultrastructural studies indicate that fully differentiated myoepithelial cells are not the. This book covers all aspects of salivary glands right from their development to the management of the diseases. Pdf salivary gland tumors are one of the most complex and relatively rare group of lesions encountered in oral pathology practice. The minor salivary glands consist of 800 small mucussecreting glands located throughout the lining of the oral cavity. Some types of neoplasms have malignant characteristics, meaning that they can infiltrate into surrounding structures and can spread to. Reason for the above criteria can be understood only when a complete. In general, neoplasms manifest two cells, the excretory duct reserve cell and the differentiation pathways similar to those found in intercalated duct reserve cell, were presented as the the development and renewal of the normal tissues hypothetical cells. Thompson salivary glands for dummies 14 carcinoma expleomorphic adenoma prognostic factors pathologic stage size histologic grade and type proportion of carcinoma extent of invasion ki67 labeling index canalicular adenoma benign salivary gland neoplasm composed of bilayered strands of basaloid cells that branch and anastomose to form variably. There has not been a single universally used classification system for salivary gland tumor. Consequently, morphogenesis, rather than differentiation, seems to be a better predictor of histogenesis in tumor diagnosis. We further consider the neoplasms and, in particular, their myoepithelial constituencies to be manifestations of escape from normal regulatory mechanisms that.
Morphogenesis, differentiation and regeneration the development of a secretoryductal apparatus is the goal of normal morphogenesis and cytodifferentiation of an exocrine gland. In the present study parotid gland specimens were collected from 25 aborted fetuses 8 male and 17 female which were fixed in formalin. Previous evaluation of her2 overexpression in salivary gland cancers indicated an incidence varying between 7 and 56%, with no clear difference among three histologically different subtypes. Histogenetic and morphogenetic concepts of salivary gland. An analysis of the normal salivary gland structure permits a morphogenetic approach to an understanding of the variability in histologic types of salivary gland tumors. These glands are composed of a number of different types of cells, and unregulated growth of these cells causes neoplasms.
Its of keen interest that all benign tumors arise from major salivary glands whereas on the other side all malignant arise from minor salivary glands. Histogenesis of salivary gland neoplasms dwivedi n, agarwal a 1, raj v, chandra s department of oral pathology and microbiology, saraswati dental college and hospital. Salivary gland tumors are relatively rare and morphologically diverse and heterogeneous tumors. Crtc1maml2 fusion transcript in high grade mucoepidermoid. T rise within sg tissue, common parotid 78% composed of cellular elements oncocytes. The major salivary glands consist of the parotid, submandibular, and sublingual glands.
Although researchers have learned much from the study of this diverse group of tumors over the years, the diagnosis and treatment of salivary gland neoplasms remain com. The authors have chosen to begin with the salivary glands, and in this report they present a concept of histogenesis and classification as well as an analysis of 1 salivarygland tumors in children, 2 the relationship between breast carcinoma and salivary. About 70% of sgts arise in the parotid gland, 10% submandibular gland, and the remainder in the minor salivary glands, with salivary gland cancer is a rare disease in which malignant cancer cells form in the tissues of the salivary glands. Salivary gland tumors are one of the most complex and relatively rare group of lesions encountered in oral pathology practice. Pdf histogenesis of salivary gland neoplasms shaleen chandra. Morphogenesis, a variant of differentiation, is a wider concept since it takes into consideration the nature of the tumor cells, their organization and their synthetic products. The parotid glands, the largest salivary glands, are just in front of the ears. Salivary gland tumours or neoplasms are tumours that form in the tissues of salivary glands. It is proposed that this class of salivary gland tumor forms a spectrum with monomorphic adenoma and myoepithelioma at the extremes and a wide range of pleomorphic adenoma between, depending on the type and degree of gene expression that. It discusses the basic structures and functions of the salivary glands in detail with easytounderstand line diagrams and photomicrographs. Kaul concerning head and neck regions, it is known that tumors of the salivary glands correspond on an average to 3% of the affections of this site and the majority being of epithelial origin 1, 2. Current concepts in diagnosis of unusual salivary gland tumors. Current classifications of salivary gland tumors separate mucoepidermoid carcinoma from other neoplasms on the basis of a number of histological features. The entity is defined as a neoplasm composed of two or more separate different tumor entities, each one of which conforms to an exactly defined tumor category, arising within the same topographical area 1 6.
Sox10 expression pattern of salivary gland tumors mirrors those of normal tissues, showing acinus and intercalated duct differentiation in a biphasic manner. Benign neoplasms of the salivary glands clinical gate. The majority of these neoplasms are benign 80% and only 20% are malignant. Morphological patterns of salivary gland tumors sindhu sharma, rupali bargotra, k. Histogenesis of salivary gland neoplasms dwivedi n.
Tumors mostly involve the major salivary glands, 42. Salivary gland neoplasms have always been an field of interest for head neck and tumors because of its diversity in histogenesis and morphogenesis. Saliva has enzymes that help digest food and antibodies that help protect against infections of the mouth and throat. As part of a phase ii trial of trastuzumab for treatment of incurable salivary gland cancer, we screened 7 tumors for her2 expression. True malignant mixed tumor carcinosarcoma of parotid. It would thus be possible to further clarify the histogenesis of salivary neoplasms by identifying ifp, in addition the. In an attempt to explain the histogenesis of salivary gland tumors, a bicellular theory of origin was proposed. The epidemiology of salivary gland tumors sgts is not well documented and does vary considerably with geographical location and ethnicity. Malignant sgts represent 6% of head and neck cancers and 0. Comparative histogenesis and morphogenesis of mucoepidermoid.
In our postulate of the histogenesis of salivary gland neoplasia, we evoke the stem cell model to account for the considerable phenotypic heterogeneity seen with these neoplasms. Neoplasms that arise in the salivary glands are relatively rare, yet they represent a wide variety of both benign and malignant histologic subtypes as seen in the image below. Pdf histogenetic and morphogenetic concepts of salivary. Histogenesis of salivary gland pleomorphic adenoma mixed. Most of these tumors are benign not cancer, but the parotid glands still are where most malignant cancerous salivary gland tumors start. Central to the histogenetic concepts is the determination of the types of cells in the normal salivary gland which are involved in the induction of the various neoplasms. Two cells, the excretory duct reserve cell and the intercalated duct reserve cell, were presented as the hypothetical cells of origin for salivary gland neoplasms. The submandibular glands are smaller and are below the jaw. Pdf histogenesis of salivary gland neoplasms researchgate. Implications for histogenesis and biologic behavior yamilet tirado department of pathology, university of.
At least two theories of tumorigenesis have been proposed for salivary gland neoplasms. Significance of ckit and sox10 in the diagnosis of. About 7 out of 10 salivary gland tumors start here. Pleomorphic adenoma is a benign salivary gland neoplasm with a diverse morphology. Histogenesis of salivary gland pleomorphic adenoma mixed tumor. Hybrid salivary gland tumors are very rare, with an incidence of less than 0. In general, neoplasms manifest two cells, the excretory duct reserve cell and the differentiation pathways similar to those found in intercalated duct reserve cell, were presented as the the development and renewal of the normal tissues hypothetical cells of origin for salivary gland neoplasms. Review and updates of immunohistochemistry in selected. Crtc1maml2 fusion transcript in high grade mucoepidermoid carcinomas of salivary and thyroid glands and warthins tumors.
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