Glossary: P

P
P16: P16 is a tumour suppressor gene. Mutations in p16 increase the risk of developing a variety of cancers, notably melanoma.
Palmoplantar: Affecting the palms of hands and soles of feet.
Papillomatous: Characterized by or pertaining to a small benign epithelial tumor, such as a wart, consisting of an overgrowth of cells on a core of smooth connective tissue.
Papillomavirus: Any of a group of viruses that cause warts and other tumors in humans. Some types of papillomaviruses that cause genital infections have been linked with various cancerous tumors.
Papule: A small, solid, usually inflammatory elevation of the skin that does not contain pus.
Papulonodule: Keratinization of the basal layer incites a dermal inflammatory reaction, leading to the classic papulonodule with a hyperkeratotic plug.
Pathology: The scientific study of the nature of disease and its causes, processes, development, and consequences.
Pedunculated: Having a peduncle or stalk.
Perineural: Situated around nervous tissue or a nerve.
Periorbital: Surrounding the eyes.
Periungual: Around the nail.
Peutz-Jeghers syndrome: (PJS) is a rare familial cancer syndrome that causes intestinal polyps, skin freckling, and an increased risk for cancer.
Phenotypic: The observable physical or biochemical characteristics, as determined by both genetic makeup and environmental influences.
Photochemotherapy: (PDT) is a form of nonsurgical cancer treatment available since the early 1990s that combines a photosensitizing medication with exposure to a laser or other specific light wavelength to kill cancer cells.
Photodynamic: The use of the energy of light in the treatment of disease.
Phototype: Skin phototype depends on the amount of melanin pigment in the skin. It is assessed on a scale from 1 to 6.
Plaque: A small disk-shaped formation or growth.
Preclinical: Of or relating to the period of a disease before the appearance of symptoms.
Pruritic: Itching.
PUVA: PUVA is a Psoralen + UVA treatment for Eczema, Psoriasis and Vitiligo, and mycosis fungoides. The Psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA. Long term use has been associated with higher rates of skin cancer.