Acantholysis is a term pathologists use to describe the loss of normal connections between skin cells. In healthy skin, the cells of the outer layer — the epidermis — are held tightly together by specialized anchor structures called desmosomes, which act like tiny molecular rivets between cells. When desmosomes are damaged or destroyed, cells lose …
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The epidermis is the thin, outermost layer of your skin. It acts as a protective shield between your body and the outside world. Although it is only about as thick as a sheet of paper in most places, the epidermis plays a crucial role in preventing harmful germs, chemicals, and physical forces from damaging your …
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Pemphigus is a group of rare autoimmune diseases that affect the skin and mucous membranes (the moist surfaces inside your mouth, nose, throat, and genitals). The outer layer of these tissues is made of keratinocytes, which are flat cells arranged like tiles on a roof. In pemphigus, the immune system produces antibodies that target specific …
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The phrase interface changes is used by pathologists to describe a specific pattern of inflammation and damage seen at the junction between the epithelium (the surface layer of cells that lines the skin, mouth, and other mucosal surfaces) and the underlying connective tissue (called the dermis in skin or lamina propria in mucosal tissue). This area …
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Atypical fibroxanthoma (AFX) is a rare, low-grade skin tumor that usually affects older adults with sun-damaged skin. It most often develops in areas exposed to long-term ultraviolet (UV) light, such as the scalp, face, and ears. Although AFX can look alarming under the microscope, with cells that vary greatly in size and shape, it is …
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Pathologists use the term atypical melanocytic proliferation when they see a skin lesion made up of melanocytes (the cells that produce pigment) that does not look completely normal under the microscope. These lesions show some unusual or atypical features but do not have all the features needed to confidently label them as benign (non-cancerous) or …
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A nevus (plural: nevi) is a medical term used to describe a growth or spot on the skin that develops from melanocytes. Melanocytes are the cells in the skin that produce melanin, the pigment responsible for skin and hair colour. Most nevi are harmless and commonly called moles, though the term nevus includes various pigmented …
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Psoriasiform dermatitis is a term for a reactive pattern of skin changes that can result from several different underlying conditions. It is called psoriasiform because the changes resemble those seen in psoriasis. What are the symptoms of psoriasiform dermatitis? People with psoriasiform dermatitis often notice red patches of skin with a dry or flaky surface …
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Keratoacanthoma is a rapidly growing but benign (noncancerous) type of skin tumour. It typically involves hair-bearing skin on the face, although other body parts can occasionally be involved. What causes keratoacanthoma? Keratoacanthoma is believed to be caused by excessive sun exposure. However, in many cases, the tumour only grows after the skin is involved in …
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Keratinocytes are the most common type of cell found in the outer layer of your skin, called the epidermis. These cells are named for the protein they produce, called keratin. Keratin is a strong, protective protein that helps make your skin, hair, and nails tough and resistant to damage. Keratinocytes form a barrier that protects …
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