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Myoepithelioma
Myoepithelioma of the head and neck, also myoepithelioma, is a salivary gland tumour of the head and neck that is usually benign. When malignant, which is exceedingly rare, they are known as malignant myoepithelioma or Myoepithelial carcinoma, and they account for 1% of the salivary tumors with poor prognosis. As the name suggests, it consists of myoepithelial cells. Classically, they are found in the parotid gland or palate. A similar tumor type may be found in the tongue, referred to as ectomesenchymal chondromyxoid tumor. Pathology The myoepithelial cells may be spindled, plasmacytoid, eithelioid or clear. Tubules or epithelium are absent, or present in a small amount (<5%) by definition. Tumours with myoepithelial cells and a large amount of tubules are classified as s (which must also contain the characteristic chondromyxoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myoepithelium
Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found in glandular epithelium as a thin layer above the basement membrane but generally beneath the luminal cells. These may be positive for alpha smooth muscle actin and can contract and expel the secretions of exocrine glands. They are found in the sweat glands, mammary glands, lacrimal glands, and salivary glands. Myoepithelial cells in these cases constitute the basal cell layer of an epithelium that harbors the epithelial progenitor. In the case of wound healing, myoepithelial cells reactively proliferate. Presence of myoepithelial cells in a hyperplastic tissue proves the benignity of the gland and, when absent, indicates cancer. Only rare cancers like adenoid cystic carcinomas contains myoepithelial cells as one of the malignant component. It can be found in endoderm or ectoderm. Markers Myoepithelial cells are true epithelial cells positive for keratins, not to be confused with myofibroblasts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectomesenchymal Chondromyxoid Tumor
Ectomesenchymal chondromyxoid tumor (ECT) is a benign intraoral tumor with presumed origin from undifferentiated (ecto)mesenchymal cells. There are some who think it is a myoepithelial tumor type. Controversies about origin * Derived from ectomesenchymal cells migrating from neural crest (there is immunophenotypic support for this theory). * Equivalent to soft tissue myoepithelioma. There is morphologic and immunohisthochemical support for this theory, with some authors advocating interchangeable terms. Signs and Symptoms Patients present with a painless, slow-growing mass usually within the tongue (most commonly the anterior dorsal tongue). There is an intact surface epithelium. Management * Surgical excision is the treatment of choice, with recurrences only when there is incomplete excision. Pathology findings Macroscopic * Submucosal circumscribed but not encapsulated nodular mass, often with entrapped muscle bundles at the edge. It may have a gelatinous appea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectomesenchymal Chondromyxoid Tumor
Ectomesenchymal chondromyxoid tumor (ECT) is a benign intraoral tumor with presumed origin from undifferentiated (ecto)mesenchymal cells. There are some who think it is a myoepithelial tumor type. Controversies about origin * Derived from ectomesenchymal cells migrating from neural crest (there is immunophenotypic support for this theory). * Equivalent to soft tissue myoepithelioma. There is morphologic and immunohisthochemical support for this theory, with some authors advocating interchangeable terms. Signs and Symptoms Patients present with a painless, slow-growing mass usually within the tongue (most commonly the anterior dorsal tongue). There is an intact surface epithelium. Management * Surgical excision is the treatment of choice, with recurrences only when there is incomplete excision. Pathology findings Macroscopic * Submucosal circumscribed but not encapsulated nodular mass, often with entrapped muscle bundles at the edge. It may have a gelatinous appea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleomorphic Adenoma
Pleomorphic adenoma is a common benign salivary gland neoplasm characterised by neoplastic proliferation of epithelial (ductal) cells along with myoepithelial components, having a malignant potentiality. It is the most common type of salivary gland tumor and the most common tumor of the parotid gland. It derives its name from the architectural Pleomorphism (variable appearance) seen by light microscopy. It is also known as "Mixed tumor, salivary gland type", which refers to its dual origin from epithelial and myoepithelial elements as opposed to its pleomorphic appearance. Clinical presentation The tumor is usually solitary and presents as a slow growing, painless, firm single nodular mass. Isolated nodules are generally outgrowths of the main nodule rather than a multinodular presentation. It is usually mobile unless found in the palate and can cause atrophy of the mandibular ramus when located in the parotid gland. When found in the parotid tail, it may present as an eversi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metastasis
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, are metastases (mets). It is generally distinguished from cancer invasion, which is the direct extension and penetration by cancer cells into neighboring tissues. Cancer occurs after cells are genetically altered to proliferate rapidly and indefinitely. This uncontrolled proliferation by mitosis produces a primary heterogeneic tumour. The cells which constitute the tumor eventually undergo metaplasia, followed by dysplasia then anaplasia, resulting in a malignant phenotype. This malignancy allows for invasion into the circulation, followed by invasion to a second site for tumorigenesis. Some cancer cells known as circulating tumor cells acquire the ability to penetrate the walls of lymphatic or blood vessels, after which they are abl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacarbazine
Dacarbazine (DTIC), also known as imidazole carboxamide, is a chemotherapy medication used in the treatment of melanoma and Hodgkin's lymphoma. For Hodgkin's it is often used together with vinblastine, bleomycin, and doxorubicin. It is given by injection into a vein. Common side effects include loss of appetite, vomiting, low white blood cell count, and low platelets. Other serious side effects include liver problems and allergic reactions. It is unclear if use in pregnancy is safe for the baby. Dacarbazine is in the alkylating antineoplastic agent, alkylating agent and purine analog families of medication. Dacarbazine was approved for medical use in the United States in 1975. It is on the WHO Model List of Essential Medicines, World Health Organization's List of Essential Medicines. Medical uses As of mid-2006, dacarbazine is commonly used as a single agent in the treatment of metastasis, metastatic melanoma, and as part of the ABVD chemotherapy regimen to treat Hodgkin's ly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathologist
Pathology is the study of the causal, causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatment, the term is often used in a narrower fashion to refer to processes and tests that fall within the contemporary medical field of "general pathology", an area which includes a number of distinct but inter-related medical specialties that diagnose disease, mostly through analysis of tissue (biology), tissue, human cell, cell, and body fluid samples. Idiomatically, "a pathology" may also refer to the predicted or actual progression of particular diseases (as in the statement "the many different forms of cancer have diverse pathologies", in which case a more proper choice of word would be "Pathophysiology, pathophysiologies"), and the affix ''pathy'' is sometimes used to indicate a state of disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleomorphic Adenoma
Pleomorphic adenoma is a common benign salivary gland neoplasm characterised by neoplastic proliferation of epithelial (ductal) cells along with myoepithelial components, having a malignant potentiality. It is the most common type of salivary gland tumor and the most common tumor of the parotid gland. It derives its name from the architectural Pleomorphism (variable appearance) seen by light microscopy. It is also known as "Mixed tumor, salivary gland type", which refers to its dual origin from epithelial and myoepithelial elements as opposed to its pleomorphic appearance. Clinical presentation The tumor is usually solitary and presents as a slow growing, painless, firm single nodular mass. Isolated nodules are generally outgrowths of the main nodule rather than a multinodular presentation. It is usually mobile unless found in the palate and can cause atrophy of the mandibular ramus when located in the parotid gland. When found in the parotid tail, it may present as an eversi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrograph
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a microscope but is only slightly magnified, usually less than 10 times. Micrography is the practice or art of using microscopes to make photographs. A micrograph contains extensive details of microstructure. A wealth of information can be obtained from a simple micrograph like behavior of the material under different conditions, the phases found in the system, failure analysis, grain size estimation, elemental analysis and so on. Micrographs are widely used in all fields of microscopy. Types Photomicrograph A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, a process referred to as ''photomicroscopy''. At a basic level, photomicroscopy may be performed simply by connecting a camera to a microscope, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H&E Stain
Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnosis and is often the gold standard. For example, when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E. H&E is the combination of two histological stains: hematoxylin and eosin. The hematoxylin stains cell nuclei a purplish blue, and eosin stains the extracellular matrix and cytoplasm pink, with other structures taking on different shades, hues, and combinations of these colors. Hence a pathologist can easily differentiate between the nuclear and cytoplasmic parts of a cell, and additionally, the overall patterns of coloration from the stain show the general layout and distribution of cells and provides a general overview of a tissue sample's structure. Thus, pattern recogniti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palate
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separated. The palate is divided into two parts, the anterior, bony hard palate and the posterior, fleshy soft palate (or velum). Structure Innervation The maxillary nerve branch of the trigeminal nerve supplies sensory innervation to the palate. Development The hard palate forms before birth. Variation If the fusion is incomplete, a cleft palate results. Function When functioning in conjunction with other parts of the mouth, the palate produces certain sounds, particularly velar, palatal, palatalized, postalveolar, alveolopalatal, and uvular consonants. History Etymology The English synonyms palate and palatum, and also the related adjective palatine (as in palatine bone), are all from the Latin ''palatum'' via Old French ''palat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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