Skin & Soft Tissue: Trichilemmal (Pilar) Cyst

Basics

• Benign Proliferation from the Hair Follicle Root Sheath
• Contain Keratin from Follicles, No Epidermis

Presentation

• Slow Growing Subcutaneous Nodule
• Normal Overlying Skin
• Most Common on the Scalp
• Physically Resemble Epidermoid Cysts

Diagnosis

• Histology Generally Required to Differentiate from Epidermoid Cysts

Treatment

• Asymptomatic: Nothing
• Symptomatic or Patient Preference (Cosmesis): Excision
  • Failure to Remove Entire Cyst Wall Significantly Increases Risk of Recurrence
  • Generally Easier to Remove than Epidermoid Cysts (Thicker Wall)