Definition
- Slow gorwing subcutaneous cyst derived from the root sheath of the hair follicle and is most commonly located on the scalp
Risk
- Often strong family hx (AD inheritance)
- Can occur sporadically or in the setting of a hereditary predisposition with autosomal dominant transmission
- Frequently multiple (70%)
- Arise in middle age
- 90% occur on scalp
Pathology
- Have a palisaded peripheral layer without a granular layer
- Contains Eosinophilic hair keratin
- May have calcification
- Filled with amorphous material
