Actinic Keratosis

**Semantic type:** Neoplastic Process

**Definition:** A precancerous lesion of the skin composed of atypical keratinocytes. It is characterized by the presence of thick, scaly patches of skin. Several histologic variants have been described, including atrophic, acantholytic, hypertrophic, proliferative, lichenoid, bowenoid, and pigmented variants.

**Synonyms:** - AK - Actinic (Solar) Keratosis - Actinic (Solar) Keratosis - Senile Hyperkeratosis - Senile Keratosis - Solar Keratosis - actinic keratosis - senile keratosis - solar keratosis