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Cyst, Sebaceous (Epidermal Cyst)

Cyst, Sebaceous (Epidermal Cyst) is a topic covered in the 5-Minute Clinical Consult.

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  • The term “sebaceous cyst” is a misnomer.
  • The correct nomenclature is “epidermoid cyst” because these structures have no sebaceous gland component (1).
  • Also known as epidermal inclusion cyst and infundibular cyst
  • A benign, encapsulated, subepidermal nodule filled with keratinaceous material produced by the stratified squamous epithelium lining the cyst wall
  • Most commonly located on face, neck, trunk
  • Synonym(s): epidermal inclusion cysts; epidermal cysts; infundibular cysts; keratin cysts; inclusion cysts
  • “True sebaceous cysts” that originate from the sebaceous gland are known as steatocystoma simplex. These are rare.


  • Most common cutaneous cyst
  • Predominant sex: male > female (2:1)
  • Predominant age: most common in 3rd to 4th decades
  • Rare before puberty
  • An estimated 1% of epidermoid cysts are found to have malignant transformation (2).
    • Squamous cell carcinomas are the most common (70%), followed by basal cell carcinoma (10%).

Etiology and Pathophysiology

  • Result from plugging of the follicular orifice
  • May occur by epidermal implantation through deep penetrating injuries
  • Often result from rupture or occlusion of pilosebaceous follicles resulting in the accumulation of keratin in the subepidermal or dermal layer of the skin
  • Spontaneous
  • Damage to hair follicle
  • Ruptured sebaceous gland
  • Congenital trauma (translocation of surface epithelial cells deep to the dermis) (3)


Most cases are sporadic and nonfamilial. Epidermoid cysts are also noted in the following:

  • Gardner syndrome (autosomal dominant)
    • Consider when encountering epidermoid cysts unusual in number or location (e.g., multiple digits or legs) (4), especially if found in conjunction with osteomas.
  • Other genetic syndromes with cystic structures resembling epidermoid cysts such as Gorlin syndrome (autosomal dominant)
  • Pachyonychia congenita type II (autosomal dominant)

General Prevention

Avoid significant sun exposure.

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Stephens, Mark B., et al., editors. "Cyst, Sebaceous (Epidermal Cyst)." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688224/all/Cyst__Sebaceous__Epidermal_Cyst_.
Cyst, Sebaceous (Epidermal Cyst). In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688224/all/Cyst__Sebaceous__Epidermal_Cyst_. Accessed August 17, 2019.
Cyst, Sebaceous (Epidermal Cyst). (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688224/all/Cyst__Sebaceous__Epidermal_Cyst_
Cyst, Sebaceous (Epidermal Cyst) [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 August 17]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688224/all/Cyst__Sebaceous__Epidermal_Cyst_.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Cyst, Sebaceous (Epidermal Cyst) ID - 1688224 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688224/all/Cyst__Sebaceous__Epidermal_Cyst_ PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -