- Indurated lesion, most common on the face
- Most common in young women, but can be seen at any age
- Frequently recur, but rarely if ever metastasize
- Associated with prior radiation therapy
- Dermal islands and cords of epithelial cells with mild atypia, focally forming lumina and keratinous cysts
- Mitotic figures are rare.
- Fibrotic to sclerotic stroma
- Invades deep into the dermis, and may infiltrate the subcutaneous fat, skeletal muscle and nerves