|
Fibroxanthoma
Atypical fibroxanthoma (AFX) of the skin is a low-grade malignancy related to malignant fibrous histiocytoma, which it resembles histologically.James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . Atypical fibroxanthoma manifests as a hard, pink or red papule or nodule that grows over the course of several months and may bleed or ulcerate. They typically occur on the head and neck. Atypical fibroxanthoma is usually asymptomatic. The exact cause of atypical fibroxanthoma is unknown. They may originate from myofibroblasts. Ultraviolet light and sun exposure are most likely risk factors. Atypical fibroxanthoma has also been associated with P53 mutations, xeroderma pigmentosum, radiation therapy, trauma, and immunosuppression. Because atypical fibroxanthoma is an uncommon condition that can mimic other disorders, skin biopsy is used to make the diagnosis. Treatment involves surgical excision. Atypical f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulcer (dermatology)
An ulcer is a sore on the skin or a mucous membrane, accompanied by the disintegration of tissue. Ulcers can result in complete loss of the Epidermis (skin), epidermis and often portions of the dermis and even subcutaneous fat. Ulcers are most common on the skin of the lower extremities and in the gastrointestinal tract. An ulcer that appears on the skin is often visible as an inflamed tissue with an area of reddened skin. A skin ulcer is often visible in the event of exposure to heat or cold, irritation, or a problem with blood circulation. They can also be caused due to a lack of mobility, which causes prolonged pressure on the tissues. This stress in the blood circulation is transformed to a skin ulcer, commonly known as Decubitus ulcer, bedsores or decubitus ulcers. Ulcers often become infection, infected, and pus forms. Signs and symptoms Skin ulcers appear as open craters, often round, with layers of skin that have eroded. The skin around the ulcer may be red, swollen, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiation Therapy
Radiation therapy or radiotherapy (RT, RTx, or XRT) is a therapy, treatment using ionizing radiation, generally provided as part of treatment of cancer, cancer therapy to either kill or control the growth of malignancy, malignant cell (biology), cells. It is normally delivered by a linear particle accelerator. Radiation therapy may be cure, curative in a number of types of cancer if they are localized to one area of the body, and have not metastasis, spread to other parts. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery to remove a primary malignant tumor (for example, early stages of breast cancer). Radiation therapy is synergistic with chemotherapy, and has been used before, during, and after chemotherapy in susceptible cancers. The subspecialty of oncology concerned with radiotherapy is called radiation oncology. A physician who practices in this subspecialty is a radiation oncologist. Radiation therapy is commonly applied to the canc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelioid Cell
Epithelioid cells (also called epithelioid histiocytes) are derivatives of activated macrophages resembling Epithelium, epithelial cells. Structure and function Structurally, epithelioid cells (when examined by light microscopy after stained with hematoxylin and eosin), are elongated, with finely granular, pale eosinophilic (pink) cytoplasm, and central, ovoid nuclei (oval or elongate), which are less dense than that of a lymphocyte. They have indistinct shape and often appear to merge into one another, forming aggregates known as giant cells. When examined by transmission electron microscopy in epithelioid cells in the field of Golgi lamellar complex are taped not only zonated, but also sleek vesicles with dense center, and also great many (more than 100) large granulas with diameters up to 340 nm and with finegranular matrix more light than in macrophage granulas, sometimes with perigranular halo. “The most prominent feature of these cells is the enormous Golgi area; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spindle Cells
Von Economo neurons, also called spindle neurons, are a specific class of mammalian cortical neurons characterized by a large spindle-shaped soma (or body) gradually tapering into a single apical axon (the ramification that ''transmits'' signals) in one direction, with only a single dendrite (the ramification that ''receives'' signals) facing opposite. Other cortical neurons tend to have many dendrites, and the bipolar-shaped morphology of von Economo neurons is unique here. Von Economo neurons are found in two very restricted regions in the brains of hominids (humans and other great apes): the anterior cingulate cortex (ACC) and the fronto-insular cortex (FI) (which each make up the salience network). In 2008, they were also found in the dorsolateral prefrontal cortex of humans. Von Economo neurons are also found in the brains of a number of cetaceans, African and Asian elephants, and to a lesser extent in macaque monkeys and raccoons. The appearance of von Economo neur ... [...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
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, 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 stratified squamous epithelium, multiple layers of flattened cells that overlie a base layer (stratum basale) composed of Epithelium#Cell types, 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 (foot), 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 . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amelanotic Melanoma
Amelanotic melanoma is a type of skin cancer in which the cells do not make any melanin. They can be pink, red, purple or of normal skin color, and are therefore difficult to diagnose correctly. They can occur anywhere on the body, just as a typical melanoma can. Often, amelanotic melanomas are mistaken for benign lesions, including dermatitis, benign neoplastic processes, or a different malignancy such as basal-cell carcinoma or squamous-cell carcinoma. A poor prognosis is associated with amelanotic lesions, partially due to the difficulty in achieving a diagnosis; however, metastatic amelanotic melanoma has a worse prognosis than other subtypes. Survival after diagnosis of amelanotic melanoma was found in a 2014 seven-year study of 3,000 patients to be poorer than for pigmented melanoma, which was attributed to the more advanced stage at diagnosis due probably to difficulty of diagnosis. The study also suggested that amelanotic melanomas might grow faster than pigmented melanoma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Cancer
Skin cancers are cancers that arise from the Human skin, skin. They are due to the development of abnormal cells (biology), cells that have the ability to invade or metastasis, spread to other parts of the body. It occurs when skin cells grow uncontrollably, forming malignant tumors. The primary cause of skin cancer is prolonged exposure to ultraviolet (UV) radiation from the sun or tanning devices. Skin cancer is the most commonly diagnosed form of cancer in humans. There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin cancer (SCC) and melanoma. The first two, along with a number of less common skin cancers, are known as nonmelanoma skin cancer (NMSC). Basal-cell cancer grows slowly and can damage the tissue around it but is unlikely to spread to distant areas or result in death. It often appears as a painless raised area of skin that may be shiny with telangiectasia, small blood vessels running over it or may present as a raised area wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclobutane Pyrimidine Dimer
Pyrimidine dimers represent molecular lesions originating from thymine or cytosine bases within DNA, resulting from photochemical reactions. These lesions, commonly linked to direct DNA damage, are induced by ultraviolet light (UV), particularly UVC, result in the formation of covalent bonds between adjacent nitrogenous bases along the nucleotide chain near their carbon–carbon double bonds, the photo-coupled dimers are fluorescent. Such dimerization, which can also occur in double-stranded RNA (dsRNA) involving uracil or cytosine, leads to the creation of cyclobutane pyrimidine dimers (CPDs) and 6–4 photoproducts. These pre-mutagenic lesions modify the DNA helix structure, resulting in abnormal non-canonical base pairing and, consequently, adjacent thymines or cytosines in DNA will form a cyclobutane ring when joined together and cause a distortion in the DNA. This distortion prevents DNA replication and transcription mechanisms beyond the dimerization site. While up to 100 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast
A fibroblast is a type of cell (biology), biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals. Structure Fibroblasts have a branched cytoplasm surrounding an elliptical, speckled cell nucleus, nucleus having two or more nucleoli. Active fibroblasts can be recognized by their abundant rough endoplasmic reticulum (RER). Inactive fibroblasts, called 'fibrocytes', are smaller, spindle-shaped, and have less RER. Although disjointed and scattered when covering large spaces, fibroblasts often locally align in parallel clusters when crowded together. Unlike the epithelial cells lining the body structures, fibroblasts do not form flat monolayers and are not restricted by a polarizing attachment to a basal lamina on one side, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Itch
An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itches leads to a scratch reflex. Unmyelinated nerve fibers for itches and pain both originate in the skin. Information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract. Classification Most commonly, an itch is felt in one place. If it is felt all over the body, then it is called ''generalized itch'' or ''generalized pruritus''. Generalized itch is infrequently a symptom of a serious underlying condition, such as cholestatic liver disease. If the sensation of itching persists for six weeks or longer, then it is called ''chronic itch'' or ''c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
