Xeroderma pigmentosum (XP) is a group of rare inherited skin disorders characterized by a heightened reaction to sunlight (photosensitivity) with skin blistering occurring after exposure to the sun. In some cases, pain and blistering may occur immediately after contact with sunlight. Acute sunburn and persistent redness or inflammation of the skin (erythema) are also early symptoms of XP. In most cases, these symptoms may be apparent immediately after birth or occur within the next three years. In other cases, symptoms may not develop until later in childhood or, more rarely, may not be recognized until adulthood. Other symptoms of XP may include discolorations, weakness and fragility, and/or scarring of the skin.

Xeroderma pigmentosum affects the eyes as well as the skin, has been associated with several forms of skin cancer, and, in some cases, may occur along with dwarfism, mental retardation, and/or delayed development.

Several subtypes of XP (i.e., XP complementation groups) have been identified, based upon different defects in the body's ability to repair DNA damaged by ultraviolet light (UV). According to the medical literature, the symptoms and findings associated with the classic form of xeroderma pigmentosum, known as XP, type A (XPA), may also occur in association with the other XP subtypes. These include: XP, type B (XPB); XP, type C (XPC), XP, type D (XPD); XP, type E (XPE); XP, type F (XPF); and XP, type G (XPG). These XP subtypes are transmitted as an autosomal recessive trait. In addition, another subtype of the disorder, known as XP, dominant type, has autosomal dominant inheritance.

In addition to the XP subtypes discussed above, researchers have identified another form of the disorder known as XP, variant type (XP-V). As with the other XP subtypes, symptoms and findings associated with the classic form of XP may also be seen in individuals with XP-V. XP-V cells have a normal or near normal ability to repair UV-induced DNA damage (nucleotide excisional repair), however, they are defective in replicating UV-damaged DNA during the division and reproduction of cells. Although the disorder's mode of inheritance is unknown, most researchers suspect that XP-V is transmitted as an autosomal recessive trait.

You could have a number of symptoms, depending on which parts of your body are affected by the disease.

Skin

The most visible signs of KS are lesions on your skin: flat, painless spots that are red or purple on light skin and bluish, brownish, or on dark skin. Unlike bruises, they don't change color when you press on them. They aren't itchy, and they don't drain. They're not dangerous.

New spots may show up each week. For some people, these lesions change slowly. They may grow into raised bumps or merge together.

Mucous membranes

KS lesions can form inside your mouth and throat, causing trouble eating or swallowing. They might also happen on your eyes and under your eyelids.

In most cases, it's not clear what causes soft tissue sarcoma.

In general, cancer occurs when cells develop errors (mutations) in their DNA. The errors make cells grow and divide out of control. The accumulating abnormal cells form a tumor that can grow to invade nearby structures and the abnormal cells can spread to other parts of the body.

The type of cell that develops the genetic mutation determines what type of soft tissue sarcoma you have. For example, angiosarcoma begins in the lining of blood vessels, while liposarcoma arises from fat cells. Some types of soft tissue sarcoma include:

• Angiosarcoma
• Dermatofibrosarcoma protuberans
• Epithelioid sarcoma
• Gastrointestinal stromal tumor (GIST)
• Kaposi's sarcoma
• Leiomyosarcoma
• Liposarcoma
• Malignant peripheral nerve sheath tumor
• Myxofibrosarcoma
• Rhabdomyosarcoma
• Solitary fibrous tumor
• Synovial sarcoma
• Undifferentiated (pleomorphic sarcoma)

Your treatment will depend on how many lesions you have, how big they are, where they are, and how well your immune system is working.

Factors that may increase your risk of sarcoma include:

• Inherited syndromes. A risk of soft tissue sarcoma can be inherited from your parents. Genetic syndromes that increase your risk include hereditary retinoblastoma, Li-Fraumeni syndrome, familial adenomatous polyposis, neurofibromatosis, tuberous sclerosis and Werner syndrome.
• Chemical exposure. Being exposed to certain chemicals, such as herbicides, arsenic and dioxin, may increase the risk of soft tissue sarcomas.
• Radiation exposure. Previous radiation treatment for other cancers can increase the risk of soft tissue sarcomas.