- Most common in over age 15 years
- Family History predisposes to multiple Trichilemmal Cysts
- Intradermal cyst involving the scalp in 90% of cases
- Similar to Epidermoid Cysts
- Most common in areas of dense Hair Follicles
- Derives from outer Hair Follicle root sheath
- Asymptomatic in most cases
- No odor (unlike Epidermal Cysts)
- Well defined, scalp oval mass
- Scalp Cysts collect keratin of cheese consistency
- Multiple Scalp Cysts may coalesce
- May become inflamed if rupture occurs
- Often associated with overlying regions of Alopecia
- Most lesions are slow growing and benign (except Proliferating Trichilemmal Tumor)
- Variants
- Proliferating Trichilemmal Tumor
- Rapidly growing lesions with overlying inflammation
- Complete surgical excision (risk of malignant transformation)
- Excision
- Complete excision in standard fashion
- See Minimal Epidermal Cyst Excision
- Habif (1996) Clinical Dermatology, p. 644-5
- Wagner (2024) Am Fam Physician 110(4): 353-61 [PubMed]