Keratinocytic epidermal hamartoma

Description

Keratinocytic epidermal hamartoma or epidermal naevus is a congenital hamartomatous epidermal malformation composed of keratinocytes. It is thought to arise as a result of somatic mutation: early embryonic mutations can give rise to extensive systematised naevi, though typically epidermal naevi are localised linear papillomatous or verrucous plaques. Histologically they exhibit acanthosis, papillomatosis and acanthosis.

Exclusions from above levels

• 5C58.12 – Congenital erythropoietic porphyria
• 5C64.20 – Acrodermatitis enteropathica
• EG63 – pilonidal cyst or sinus