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Epidermoid cyst in Adult
See also in: Anogenital,Hair and Scalp
Other Resources UpToDate PubMed

Epidermoid cyst in Adult

See also in: Anogenital,Hair and Scalp
Contributors: Susan Burgin MD, Belinda Tan MD, PhD, Noah Craft MD, PhD
Other Resources UpToDate PubMed


An epidermoid cyst, also known as an epidermal inclusion cyst, is a semi-solid cyst. The cyst wall is stratified squamous epithelium, and the contents consist of macerated keratin and lipid-rich debris. The epidermoid cyst is a common lesion that can arise on the face, trunk, extremities, in the mouth, or on the genitals at any age. They are more common in men. Several etiologic factors have been implicated in the formation of epidermoid cysts, including traumatic or iatrogenic implantation of epidermal elements, sequestration of epidermal rests, occlusion of the eccrine duct or pilosebaceous unit, and human papillomavirus (HPV) infection. Epidermoid cysts are a feature of several hereditary syndromes, such as Gardner syndrome, pachyonychia congenita, and the basal cell nevus syndrome. It is rare to see an epidermoid cyst in a pre-pubertal patient; in such cases, other diagnoses should be carefully considered.

Epidermoid cysts are benign and usually asymptomatic, but they may be painful if ruptured or infected. Rarely, malignancies such as basal cell carcinoma, squamous cell carcinoma, and mycosis fungoides have developed within these cysts.


L72.0 – Epidermal cyst

419893006 – Epidermoid cyst

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Differential Diagnosis & Pitfalls

  • Pilar cyst (trichilemmal cyst) – most commonly located on the scalp; usually has a firmer consistency on palpation
  • Lipoma
  • Pilomatricoma
  • Skin bacterial abscess
  • Eruptive vellus hair cyst
  • Calcinosis cutis
  • Steatocystoma multiplex
  • Rheumatoid nodule
  • Cutaneous dermoid cyst
  • Branchial cleft cyst or sinus or Thyroglossal duct cyst
  • Proliferating pilar tumor
  • Chondroid syringoma
  • Metastatic cutaneous carcinoma

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Last Reviewed:05/08/2017
Last Updated:06/20/2017
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Epidermoid cyst in Adult
See also in: Anogenital,Hair and Scalp
A medical illustration showing key findings of Epidermoid cyst : Cyst, Face, Neck, Scalp, Smooth nodule, Trunk
Clinical image of Epidermoid cyst - imageId=3463753. Click to open in gallery.  caption: 'A close-up of a yellowish nodule with a central keratin-filled punctum.'
A close-up of a yellowish nodule with a central keratin-filled punctum.
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