Epidermal Inclusion Cyst

Overview
  • Epidermal Inclusion Cysts (EICs), also known as Epidermoid Cysts, appear as firm, dome-shaped, subcutaneous, flesh-colored nodules, often with a central punctum. They contain a cheesy, foul-smelling material that can occasionally be expressed through the punctum.
Pathogenesis and Morphology
  • EICs are created by insertion of an independent section of the epidermis into the dermis. These insertions create cyst like structures with an inwardly proliferating stratified squamous wall and central accumulation of keratin and lipid debris, thus yielding expansion of the cyst over time. The precise etiology of EIC formation is unknown and may occur due to cutaneous trauma or occlusion of pilosebaceous units.
Treatment
  • Treatment is by excision of the entire cyst, including the cyst wall. The EIC will simply recur if the central keratin and lipid debris is drained without removal of the cyst epithelium itself.