Pilar Sheath Acanthoma

**Semantic type:** Neoplastic Process

**Definition:** A benign, small, papular or nodular skin neoplasm that usually arises above the upper lip. It is characterized by an epithelial proliferation with a central cavity. The cavity wall is lined with keratinocytes.

**Synonyms:** - Acanthoma of Pilar Sheath - Acanthoma of the Pilar Sheath - Infundibular Adenoma - Infundibuloisthmicoma