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Seborrheic Keratosis
A seborrheic keratosis is a non-cancerous ( benign) skin tumour that originates from cells, namely keratinocytes, in the outer layer of the skin called the epidermis. Like liver spots, seborrheic keratoses are seen more often as people age. The tumours (also called lesions) appear in various colours, from light tan to black. They are round or oval, feel flat or slightly elevated, like the scab from a healing wound, and range in size from very small to more than across. They are often associated with other skin conditions, including basal cell carcinoma. Sometimes, seborrheic keratosis and basal cell carcinoma occur at the same location. At clinical examination, a differential diagnosis considers warts and melanomas. Because only the top layers of the epidermis are involved, seborrheic keratoses are often described as having a "pasted-on" appearance. Some dermatologists refer to seborrheic keratoses as "seborrheic warts", because they resemble warts, but strictly speaking, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leser–Trélat Sign
The Leser–Trélat sign is the explosive onset of multiple seborrheic keratoses (many pigmented skin lesions), often with an inflammation, inflammatory base. This can be a sign of internal malignancy as part of a paraneoplastic syndrome. In addition to the development of new lesions, preexisting ones frequently increase in size and become symptomatic. Associations Although most associated neoplasms are gastrointestinal adenocarcinomas (Gastric adenocarcinoma, stomach, Liver cancer, liver, Colorectal adenocarcinoma, colorectal and Pancreatic adenocarcinoma, pancreas), malignancies of the Breast cancer, breast, Lung cancer, lung, and Bladder cancer, urinary tract, as well as Lymphoma, lymphoid tissue, have been associated with this distinctive rash. It is likely that various cytokines and other growth factors produced by the neoplasm are responsible for the abrupt appearance of the seborrheic keratoses. In some cases, paraneoplastic acanthosis nigricans (35% of patients), florid c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seborrheic Keratosis Closup
Seborrhoeic dermatitis (also spelled seborrheic dermatitis in American English) is a long-term skin disorder. Symptoms include flaky, scaly, greasy, and occasionally itchy and inflamed skin. Areas of the skin rich in oil-producing glands are often affected including the scalp, face, and chest. It can result in social or self-esteem problems. In babies, when the scalp is primarily involved, it is called cradle cap. Mild seborrhoeic dermatitis of the scalp may be described in lay terms as dandruff due to the dry, flaky character of the skin. However, as dandruff may refer to any dryness or scaling of the scalp, not all dandruff is seborrhoeic dermatitis. Seborrhoeic dermatitis is sometimes inaccurately referred to as seborrhoea. The cause is unclear but believed to involve a number of genetic and environmental factors. Risk factors for seborrhoeic dermatitis include poor immune function, Parkinson's disease, and alcoholic pancreatitis. The condition may worsen with stress ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanocyte
Melanocytes are melanin-producing neural-crest, neural crest-derived cell (biology), cells located in the bottom layer (the stratum basale) of the skin's epidermis (skin), epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and heart found in many mammals and birds. Melanin is a dark pigment primarily responsible for skin color. Once synthesized, melanin is contained in special organelles called melanosomes which can be transported to nearby keratinocytes to induce pigmentation. Thus darker skin tones have more melanosomes present than lighter skin tones. Functionally, melanin serves as protection against Ultraviolet, UV radiation. Melanocytes also have a role in the immune system. Function Through a process called melanogenesis, melanocytes produce melanin, which is a pigment found in the human skin, skin, human eye, eyes, hair, nasal cavity, and inner ear. This melanogenesis leads to a long-lasting pigmentation, which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratinocyte
Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the basal layer (''stratum basale'') of the skin are sometimes referred to as basal keratinocytes. Keratinocytes form a barrier against environmental damage by heat, UV radiation, water loss, pathogenic bacteria, fungi, parasites, and viruses. A number of structural proteins, enzymes, lipids, and antimicrobial peptides contribute to maintain the important barrier function of the skin. Keratinocytes differentiate from epidermal stem cells in the lower part of the epidermis and migrate towards the surface, finally becoming corneocytes and eventually being shed, which happens every 40 to 56 days in humans. Function The primary function of keratinocytes is the formation of a barrier against environmental damage by heat, UV radiation, dehydration, pathogenic bacteria, fungi, parasites, and viruses. Pathoge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distal Tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects the knee with the ankle. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane. The tibia is connected to the fibula by the interosseous membrane of leg, forming a type of fibrous joint called a syndesmosis with very little movement. The tibia is named for the flute ''tibia''. It is the second largest bone in the human body, after the femur. The leg bones are the strongest long bones as they support the rest of the body. Structure In human anatomy, the tibia is the second largest bone next to the femur. As in other vertebrates the tibia is one of two bones in the lower leg, the other being the fibula, and is a component of the knee and ankle joints. The tibia together with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histologically
Histology, also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures visible without a microscope. Although one may divide microscopic anatomy into ''organology'', the study of organs, ''histology'', the study of tissues, and ''cytology'', the study of cell (biology), cells, modern usage places all of these topics under the field of histology. In medicine, histopathology is the branch of histology that includes the microscopic identification and study of diseased tissue. In the field of paleontology, the term paleohistology refers to the histology of fossil organisms. Biological tissues Animal tissue classification There are four basic types of animal tissues: muscle tissue, nervous tissue, connective tissue, and epithelial tissue. All animal tissues are considered to be subtypes of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collagen
Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in cartilage, bones, tendons, ligaments, and skin. Vitamin C is vital for collagen synthesis. Depending on the degree of biomineralization, mineralization, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in corneas, blood vessels, the Gut (anatomy), gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes 1% to 2% of muscle tissue and 6% by weight of skeletal muscle. The fibroblast is the most common cell creating collagen in animals. Gelatin, which is used in food and industry, is collagen t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermis (skin)
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of multiple layers of flattened cells that overlie a base layer ( stratum basale) composed of columnar cells arranged perpendicularly. The layers of cells develop from stem cells in the basal layer. The thickness of the epidermis varies from 31.2μm for the penis to 596.6μm for the sole of the foot with most being roughly 90μm. Thickness does not vary between the sexes but becomes thinner with age. The human epidermis is an example of epithelium, particularly a stratified squamous epithelium. The word epidermis is derived through Latin , itself and . Something related to or part of the epidermis is termed epidermal. Structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Biopsy
Skin biopsy is a biopsy technique in which a skin lesion is removed to be sent to a pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin biopsies are also done by family physicians, internists, surgeons, and other specialties. However, performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited, and therefore doctors and patients may forgo traditional biopsy techniques and instead choose Mohs surgery. There are four main types of skin biopsies: shave biopsy, punch biopsy, excisional biopsy, and incisional biopsy. The choice of the different skin biopsies is dependent on the suspected diagnosis of the skin lesion. Like most biopsies, patient consent and anesthesia (usually lidocaine injected into the skin) are prerequisites. Types Shave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold Standard (test)
In medicine and medical statistics, the gold standard, criterion standard, or reference standard is the diagnostic test or benchmark that is the best available under ''reasonable'' conditions. It is the test against which new tests are compared to gauge their validity, and it is used to evaluate the efficacy of treatments. The meaning of "gold standard" may differ between practical medicine and the statistical ideal. With some medical conditions, only an autopsy can guarantee diagnostic certainty. In these cases, the gold standard test is the best test that keeps the patient alive, and even gold standard tests can require follow-up to confirm or refute the diagnosis. History The term 'gold standard' in its current sense in medical research was coined by Rudd in 1979, in reference to the monetary gold standard. In medicine "Gold standard" can refer to popular clinical endpoints by which scientific evidence is evaluated. For example, in resuscitation research, the "gold standar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squamous Cell Carcinoma
Squamous-cell carcinoma (SCC), also known as epidermoid carcinoma, comprises a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the lining of the respiratory and digestive tracts. The squamous-cell carcinomas of different body sites can show differences in their presented symptoms, natural history, prognosis, and response to treatment. By body location Human papillomavirus infection has been associated with SCCs of the oropharynx, lung, fingers, and anogenital region. Head and neck cancer About 90% of cases of head and neck cancer (cancer of the mouth, nasal cavity, nasopharynx, throat and associated structures) are due to SCC. Skin Cutaneous squamous-cell carcinoma is the second most common skin cancer, accounting for over 1 million cases in the United States each year. Thyroid Primary squamous-cell carcinoma of the thyroid shows an aggressive biologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condyloma Acuminata
Genital warts are a sexually transmitted infection caused by certain types of human papillomavirus (HPV). They may be flat or project out from the surface of the skin, and their color may vary; brownish, white, pale yellow, pinkish-red, or gray. There may be a few individual warts or several, either in a cluster or merged together to look cauliflower-shaped. They can be itchy and feel burning. Usually they cause few symptoms, but can occasionally be painful. Typically they appear one to eight months following exposure. Warts are the most easily recognized symptom of genital HPV infection. HPV types 6 and 11 are responsible for causing majority of genital warts whereas HPV types 16, 18, 31, 33, and 35 are also occasionally found. It is spread through direct skin-to-skin contact, usually during oral, manual, vaginal, or anal sex with an infected partner. Diagnosis is generally based on symptoms and can be confirmed by biopsy. The types of HPV that cause cancer are not the same a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
