Nevus: Causes

Pathogenesis (development of disease)

Nevus refers to a benign (benign) circumscribed malformation of the skin (dermis or epidermis) or mucosa in which normal cells or tissues are increased, decreased, or irregular. Nevi are hamartomas (tissue changes resulting from defectively differentiated or scattered germinal tissue) of the skin or mucosa. The brownish colored nevi of pigment-forming cells (pigment nevi; colloquially called “mole” or “birthmark“) represent the most common navi. However, there are many other types of nevi that do not consist of pigment-forming melanocytes or nevus cells (navus cell nevi, NZN). These consist of blood vessel cells (hemangiomas, see below), connective tissue cells, glandular cells (e.g., nevus sebaceus, sebaceous gland nevus; sweat gland nevus) or other cells.

The nevus flammeus is caused by vasodilatation in the dermis. Hemangiomas are conditioned by vascular neoplasms in the skin.

Etiology (causes)

Biographic causes

  • Genetic burden from parents, grandparents.
  • Ethnic affiliation
  • Skin type – fair skin type (Fitzpatrick I-II) (melanocytic nevi).
  • Occupations – occupations with high UV exposure.

Behavioral causes

  • UV exposure (especially: UV-B radiation/solariums) – the number of melanocytic nevi (MN; moles)) correlates closely with frequency and intensity of sun exposure in children.

Disease-related causes.

Liver, gallbladder, and bile ducts – Pancreas (pancreas) (K70-K77; K80-K87).

  • Advanced liver disease, unspecified, may lead to the formation of spider nevi (synonyms: spider nevus, star nevus, or vascular spider)

Injuries, poisonings and other consequences of external causes (S00-T98).

  • Infected injuries can lead to the formation of granuloma pyogenicum (synonym: pyogenic granuloma; acquired benign (benign) vascular skin tumor of the hemangioma group, also called hemangioma or strawberry spot)

Medication