Hidroacanthoma simplex with invasive growth.
Hidroacanthoma simplex is a benign tumor of the skin, macroscopically resembling seborrheic keratosis or Bowen's disease, and histologically revealing intraepidermal focal growth of epithelial cells. A case of hidroacanthoma simplex with a malignant portion is presented in this report. The present case revealed mostly histologic characteristics of hidroacanthoma simplex, but the central portion of the tumor showed downward invasive growth with increased cellular atypia. The malignant change of hidroacanthoma simplex is discussed in relation to eccrine porocarcinoma (malignant eccrine poroma).
D006801:Humans; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology*