Question: What is (are) Phacomatosis pigmentovascularis ?
Answer: Phacomatosis pigmentovascularis (PPV) is a skin and blood vessel disorder that is present from birth. Common signs and symptoms include port wine stain and pigmentary lesions, such as melanocytic nevi or epidermal nevi. A variety of classification systems have been proposed for PPV, largely depending on what type of pigmentary lesion is present. Around half of individuals with PPV have systemic disease, meaning that body systems other than the skin are affected. Systemic symptoms can vary greatly from person to person. PPV is not inherited, but is thought to be caused by a genetic phenomenon called twin spotting.
Source: GARD

Question: What causes Phacomatosis pigmentovascularis ?
Answer: What causes phacomatosis pigmentovascularis? Phacomatosis pigmentovascularis (PPV) is thought to occur as a result of a change in the arrangement of a small piece of genetic material in a developing embryo. Because of this change some of the baby's body cells carry two copies of recessive gene mutations while the majority of his or her body cells carry only one. Having two copies of the recessive gene mutations result in a diseased cell (and symptoms of PPV). This phenomenon is called twin spotting. PPV occurs by chance, it is not inherited, and affects only a subset of the body's cells. As a result risk to future offspring is very small.
Source: GARD

Question: How to diagnose Phacomatosis pigmentovascularis ?
Answer: How might phacomatosis pigmentovascularis be diagnosed? Diagnosis of phacomatosis pigmentovascularis is based primarily on physical evaluation and appearence of the skin lesions.
Source: GARD