II. Epidemiology

  1. Most common skin cyst

III. Causes

  1. Ruptured Pilosebaceous Follicle (acne comedone)
  2. Local Trauma buries surface epithelium under skin

IV. Pathophysiology

  1. Previously known as Sebaceous Cysts but not derived from sebaceous tissue
  2. Common Locations
    1. Head and Neck
    2. Face
    3. Ears
    4. Chest
    5. Back
  3. Lesion
    1. Implanted epidermal elements into deeper dermal layers
    2. Cyst wall: stratified squamous epithelium
    3. Central punctum is typically present on close exam (hallmark finding of Sebaceous Cyst)
    4. Cyst contents
      1. Does not contain Sebaceous Glands
      2. Keratin and lipid
      3. Breakdown products
      4. Bacterial Infection
  4. Cyst rupture effect (keratin spills into Dermis)
    1. Significant inflammation
    2. Lesion may scar or become infected

V. Symptoms

  1. Usually asymptomatic
  2. Soft, yellow keratin discharge may have foul odor

VI. Signs

  1. Round, mobile, smooth surfaced, discrete Nodule
  2. Slow growing lesion from 5 mm to 5 cm in diameter
  3. Visible pore may be present at center of lesions
  4. May be inflamed if cyst has ruptured

VII. Differential Diagnosis

  1. See Soft Tissue Mass
  2. See site specific (e.g. Neck Masses in Children)
  3. Lipoma
  4. Milia (1-2 mm lesion)
    1. Puncture with needle, express with comedone extractor
  5. Dermoid cyst
    1. May extend intracranially (CT Head before excision)
    2. Locations
      1. Follow Cleavage Lines
      2. Sublingual
      3. Periorbital
      4. Base of nose
  6. Gardner's Syndrome
    1. Autosomal Dominant condition associated with Colonic Polyps and Colon Cancer
    2. Children with Sebaceous Cysts
    3. Adults with Sebaceous Cysts in rare location (fingers, toes)
    4. Multiple Lipomas, fibromas, osteomas

VIII. Types: Variations with multiple lesions

  1. Steatocystoma Multiplex
    1. Numerous 2-3mm lesions on trunk, arm, axilla, thigh
  2. Favre-Racouchot Syndrome
    1. Multiple facial lesions due to sun damage

IX. Management

  1. Non-inflamed cyst
    1. Small to moderate sized cysts
      1. See Minimal Epidermal Cyst Excision
    2. Large Cysts (2 cm or larger)
      1. Complete excision in standard fashion
      2. Remove cyst intact via Blunt Dissection
  2. Inflamed or infected cyst
    1. Warm compresses
    2. Incision and Drainage

X. Complications

  1. Cyst rupture
  2. Cyst inflammation or infection

XI. References

  1. Habif (1996) Clinical Dermatology, p. 644
  2. White (1994) Regional Dermatology, p. 27
  3. Higgins (2015) Am Fam Physician 92(7): 601-7 [PubMed]
  4. Zuber (2002) Am Fam Physician 65(7):1409-12 [PubMed]

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Related Studies

Ontology: Epithelial cyst (C0014511)

Definition (MSH) Intradermal or subcutaneous saclike structure, the wall of which is stratified epithelium containing keratohyalin granules.
Concepts Anatomical Abnormality (T190)
MSH D004814
ICD9 706.2
ICD10 L72.0 , K09.8, L72.3
SnomedCT 416292009, 419893006, 201231006, 390838001, 156420007, 87595009, 87373006, 254672005, 201324005, 390837006, 418323001, 399999000, 419603000, 419670003, 417992006, 418630001
English Wen, Cysts, Epidermal, Cysts, Epidermoid, Cysts, Sebaceous, Epidermal Cyst, Epidermal Cysts, Epidermoid Cyst, Epidermoid Cysts, Sebaceous Cyst, Sebaceous Cysts, Cyst, Epidermal, Cyst, Epidermoid, Cyst, Sebaceous, EPIDERMOID CYSTS, Epidermoid cysts, sebaceous cyst (diagnosis), sebaceous cyst, Cyst epidermal, Cyst sebaceous, Infundibular Cyst, Epidermal Cyst [Disease/Finding], sebaceous cysts, Cyst;epidermoid, Cyst;sebaceous, epidermal cyst, keratin cyst, cyst epithelial, epithelial cyst, cysts epithelial, cysts keratinous, epidermoid cysts, epidermal cysts, wen, wens, keratinous cyst, Epidermal cyst (disorder), Keratinising cyst, Keratinizing cyst, Keratinizing cyst (disorder), Epithelial cyst, cyst; epidermal, cyst; epithelial, cyst; sebaceous, epidermal; cyst, epithelial; cyst, sebaceous; cyst, Epidermal cyst, NOS, Epithelial cyst, NOS, Epithelial Cyst, Keratin Cyst, Keratinizing Cyst, Keratinous Cyst, epidermoid cyst, Epidermal cyst, Epidermoid cyst, Sebaceous cyst, Keratin cyst, Keratinous cyst, Epidermoid cyst (disorder), Sebaceous cyst (morphologic abnormality), Epidermoid cyst (morphologic abnormality), Epidermoid cyst of skin (disorder), Epidermoid cyst of skin, Keratinising cyst of skin, Keratinizing cyst (morphologic abnormality), Keratinizing cyst of skin (disorder), Keratinizing cyst of skin
Spanish quiste epidermoide (trastorno), quiste epidermoide, quiste sebáceo (anomalía morfológica), quiste sebáceo, quiste epidermoide (anomalía morfológica), quiste epidermoide cutáneo (trastorno), quiste epidermoide cutáneo, quiste queratinizante (anomalía morfológica), quiste queratinizante de la piel (trastorno), quiste queratinizante de la piel, Quiste sebáceo, Quiste epidérmico, Quiste epidermoide, quiste epidérmico, quiste epidérmico (trastorno), quiste epitelial, quiste de queratina, quiste epidermoideo, lupia, quiste queratinizante (trastorno), quiste queratinizante, Quiste Epidérmico, Quiste Epidermoide, Quiste Sebáceo
Dutch atheroomcyste, epidermale cyste, epidermoïde cyste, cyste; epidermaal, cyste; epitheliaal, cyste; talgklier, epidermaal; cyste, epitheliaal; cyste, talgklier; cyste, Atheroomcyste, Cyste, epidermaal, Epidermale cyste, Talgcyste, Epidermoïdcyste
German Zyste der Haut, Atherom, Talgdruesenzyste, Zyste der Talgdruese, Epidermalzyste, Epidermiszyste, Epidermoidzyste, Talgdrüsenzyste
Italian Cisti dell'epidermide, Cisti epidermoide, Cisti sebacea, Cisti epidermica
Portuguese Quisto sebáceo, Quisto epidermóide, Quisto epidérmico, Cisto Epidermoide, Cisto Epidérmico, Cisto Sebáceo
Japanese 脂腺嚢腫, シセンノウシュ, ヒョウヒノウホウ, ルイヒョウヒノウホウ, 外毛根鞘性嚢腫, 毛髪嚢腫, 皮脂嚢胞, 類表皮嚢胞, エピデルモイドシスト, 毛鞘嚢胞, 毛嚢胞, 外毛根鞘嚢腫, 上皮嚢胞, 外毛根鞘性嚢胞, 表皮嚢腫, 類表皮嚢腫, 粉瘤, 外毛根鞘嚢胞, 表皮のう胞, 表皮様嚢腫, 類上皮嚢腫, アテローム(粉瘤), 表皮嚢胞
Swedish Epidermoidcysta
Czech epidermální cysta, Epidermální cysta, Epidermoidní cysta, Mazová cysta, mazová cysta
Finnish Epidermaalikysta
Korean 표피낭
Polish Torbiel naskórkowa
Hungarian Cysta sebacea, Epidermoid cysta, Epidermalis hólyag, Sebaceus cysta, Epidermalis cysta
Norwegian Epidermoidcyste
French Kyste épidermique, Loupe, Kyste épidermoïde, Kyste sébacé