Laboratory Studies

Laboratory studies are typically unnecessary; however, with recurrent infection or lack of response to antibiotics, a culture and sensitivity may be obtained.

Imaging Studies

If an epidermoid cyst is suspected in an unusual location, such as breast, bone, or intracranial locations, imaging with ultrasonography, radiography, CT scanning, or MRI is appropriate.

Other Tests

Fine-needle aspiration has been used to help diagnose epidermoid cysts in unusual locations, such as the breast. Smears of aspirated material stained with Wright-Giemsa stain demonstrate nucleated keratinocytes and wavy keratin material.^[1]

Histologic Findings

Epidermoid cysts are lined with stratified squamous epithelium that contains a granular layer. Laminated keratin contents are noted inside the cyst. An inflammatory response may be present in cysts that have ruptured. Older cysts may exhibit calcification. Pilomatrical differentiation may be noted, especially in patients with Gardner syndrome.^[38]

Note the images below.

Cyst containing keratinous material (hematoxylin and eosin, original magnification X1.6).

View Media Gallery

Higher-magnification view of the cyst wall of the cyst in Media File 3 demonstrates a true epidermis with a granular layer and adjacent laminated keratinous material (hematoxylin and eosin, original magnification X20).

View Media Gallery

Treatment & Management

Handa U, Kumar S, Mohan H. Aspiration cytology of epidermoid cyst of terminal phalanx. Diagn Cytopathol. 2002 Apr. 26(4):266-7. [QxMD MEDLINE Link].
Weir CB, St.Hilaire NJ. Epidermal Inclusion Cyst. StatPearls [Internet]. 2020 Jan. [QxMD MEDLINE Link]. [Full Text].
Zito PM, Scharf R. Epidermoid Cyst (Sebaceous Cyst). StatPearls [Internet]. 2020 Jan. [QxMD MEDLINE Link]. [Full Text].
Aloi F, Tomasini C, Pippione M. Mycosis fungoides and eruptive epidermoid cysts: a unique response of follicular and eccrine structures. Dermatology. 1993. 187(4):273-7. [QxMD MEDLINE Link].
Barr RJ, Headley JL, Jensen JL, Howell JB. Cutaneous keratocysts of nevoid basal cell carcinoma syndrome. J Am Acad Dermatol. 1986 Apr. 14(4):572-6. [QxMD MEDLINE Link].
Bauer B. Carcinoma arising in a sebaceous cyst. IMJ Ill Med J. 1979 Sep. 156(3):174-6. [QxMD MEDLINE Link].
Cameron DS, Hilsinger RL Jr. Squamous cell carcinoma in an epidermal inclusion cyst: case report. Otolaryngol Head Neck Surg. 2003 Jul. 129(1):141-3. [QxMD MEDLINE Link].
Delacretaz J. Keratotic basal-cell carcinoma arising from an epidermoid cyst. J Dermatol Surg Oncol. 1977 May-Jun. 3(3):310-1. [QxMD MEDLINE Link].
King LA, Barr RJ, Gottschalk HR. Mycosis fungoides with underlying epidermoid cysts. Arch Dermatol. 1979 May. 115(5):622. [QxMD MEDLINE Link].
Levine DJ, Robertson DB, Varma VA. Familial subconjunctival epithelial cysts associated with the nevoid basal cell carcinoma syndrome. Arch Dermatol. 1987 Jan. 123(1):23-4. [QxMD MEDLINE Link].
Lopez-Rios F, Rodriguez-Peralto JL, Castano E, Benito A. Squamous cell carcinoma arising in a cutaneous epidermal cyst: case report and literature review. Am J Dermatopathol. 1999 Apr. 21(2):174-7. [QxMD MEDLINE Link].
Ogata K, Ikeda M, Miyoshi K, et al. Naevoid basal cell carcinoma syndrome with a palmar epidermoid cyst, milia and maxillary cysts. Br J Dermatol. 2001 Sep. 145(3):508-9. [QxMD MEDLINE Link].
Perse RM, Klappenbach RS, Ragsdale BD. Trabecular (Merkel cell) carcinoma arising in the wall of an epidermal cyst. Am J Dermatopathol. 1987 Oct. 9(5):423-7. [QxMD MEDLINE Link].
Tanaka M, Terui T, Sasai S, Tagami H. Basal cell carcinoma showing connections with epidermal cysts. J Eur Acad Dermatol Venereol. 2003 Sep. 17(5):581-2. [QxMD MEDLINE Link].
Swygert KE, Parrish CA, Cashman RE, Lin R, Cockerell CJ. Melanoma in situ involving an epidermal inclusion (infundibular) cyst. Am J Dermatopathol. 2007 Dec. 29(6):564-5. [QxMD MEDLINE Link].
Egawa K, Kitasato H, Honda Y, Kawai S, Mizushima Y, Ono T. Human papillomavirus 57 identified in a plantar epidermoid cyst. Br J Dermatol. 1998 Mar. 138(3):510-4. [QxMD MEDLINE Link].
Egawa K, Honda Y, Inaba Y, Ono T, De Villiers EM. Detection of human papillomaviruses and eccrine ducts in palmoplantar epidermoid cysts. Br J Dermatol. 1995 Apr. 132(4):533-42. [QxMD MEDLINE Link].
Egawa K, Honda Y, Inaba Y, Kojo Y, Ono T, de Villiers EM. Multiple plantar epidermoid cysts harboring carcinoembryonic antigen and human papillomavirus DNA sequences. J Am Acad Dermatol. 1994 Mar. 30(3):494-6. [QxMD MEDLINE Link].
Egawa K, Inaba Y, Ono T, Arao T. Cystic papilloma' in humans? Demonstration of human papillomavirus in plantar epidermoid cysts. Arch Dermatol. 1990 Dec. 126(12):1599-603. [QxMD MEDLINE Link].
Egawa K, Egawa N, Honda Y. Human papillomavirus-associated plantar epidermoid cyst related to epidermoid metaplasia of the eccrine duct epithelium: a combined histological, immunohistochemical, DNA-DNA in situ hybridization and three-dimensional reconstruction analysis. Br J Dermatol. 2005 May. 152(5):961-7. [QxMD MEDLINE Link].
Kato N, Ueno H. Two cases of plantar epidermal cyst associated with human papillomavirus. Clin Exp Dermatol. 1992 Jul. 17(4):252-6. [QxMD MEDLINE Link].
Kawase M, Honda M, Niimura M. Detection of human papillomavirus type 60 in plantar cysts and verruca plantaris by the in situ hybridization method using digoxigenin labeled probes. J Dermatol. 1994 Oct. 21(10):709-15. [QxMD MEDLINE Link].
Kitasato H, Egawa K, Honda Y, Ono T, Mizushima Y, Kawai S. A putative human papillomavirus type 57 new subtype isolated from plantar epidermoid cysts without intracytoplasmic inclusion bodies. J Gen Virol. 1998 Aug. 79 (Pt 8):1977-81. [QxMD MEDLINE Link].
Lee S, Lee W, Chung S, et al. Detection of human papillomavirus 60 in epidermal cysts of nonpalmoplantar location. Am J Dermatopathol. 2003 Jun. 25(3):243-7. [QxMD MEDLINE Link].
Morgan MB, Stevens GL, Somach S, Tannenbaum M. Carcinoma arising in epidermoid cyst: a case series and aetiological investigation of human papillomavirus. Br J Dermatol. 2001 Sep. 145(3):505-6. [QxMD MEDLINE Link].
Park HS, Kim WS, Lee JH, et al. Association of human papillomavirus infection with palmoplantar epidermal cysts in Korean patients. Acta Derm Venereol. 2005. 85(5):404-8. [QxMD MEDLINE Link].
Rios-Buceta LM, Fraga-Fernandez J, Fernandez-Herrera J. Human papillomavirus in an epidermoid cyst of the sole in a non-Japanese patient. J Am Acad Dermatol. 1992 Aug. 27(2 Pt 2):364-6. [QxMD MEDLINE Link].
Frank E, Macias D, Hondorp B, Kerstetter J, Inman JC. Incidental Squamous Cell Carcinoma in an Epidermal Inclusion Cyst: A Case Report and Review of the Literature. Case Rep Dermatol. 2018 Jan-Apr. 10 (1):61-68. [QxMD MEDLINE Link].
Egawa K, Kitasato H, Ono T. A palmar epidermoid cyst, showing histological features suggestive of eccrine duct origin, developing after a bee-sting. Br J Dermatol. 2000 Aug. 143(2):469-70. [QxMD MEDLINE Link].
Pandhi R, Gupta S, Kumar B. Multiple epidermoid cysts on photodamaged skin sebaceous gland hyperplasia and senile. J Eur Acad Dermatol Venereol. 2001 Mar. 15(2):184-5. [QxMD MEDLINE Link].
Bechara FG, Sand M, Rotterdam S, Altmeyer P, Hoffmann K. Multiple epidermal inclusion cysts after axillary liposuction-curettage: a rare complication of a frequent procedure. Int J Dermatol. 2008 Nov. 47(11):1197-8. [QxMD MEDLINE Link].
Leppard B, Bussey HJ. Epidermoid cysts, polyposis coli and Gardner's syndrome. Br J Surg. 1975 May. 62(5):387-93. [QxMD MEDLINE Link].
Besser FS. Pachyonychia congenita with epidermal cysts and teeth at birth: 4th generation. Br J Dermatol. 1971 Jan. 84(1):95-6. [QxMD MEDLINE Link].
Takeshita T, Takeshita H, Irie K. Eruptive vellus hair cyst and epidermoid cyst in a patient with pachyonychia congenita. J Dermatol. 2000 Oct. 27(10):655-7. [QxMD MEDLINE Link].
Shet T, Desai S. Pigmented epidermal cysts. Am J Dermatopathol. 2001 Oct. 23(5):477-81. [QxMD MEDLINE Link].
Karacal N, Topal U, Kutlu N. Popliteal epidermoid cyst: an unusual location. Plast Reconstr Surg. 2004 Sep 1. 114(3):830-1. [QxMD MEDLINE Link].
Baran R, Broutart JC. Epidermoid cyst of the thumb presenting as pincer nail. J Am Acad Dermatol. 1988 Jul. 19(1 Pt 1):143-4. [QxMD MEDLINE Link].
Lamprou K, Plataras C, Chorti M, Christianakis E. Cutaneous Hybrid Tumor Composed of Epidermal Cyst and Cystic Pilomatricoma: Unusual Presentation in a Child. Int J Trichology. 2016 Oct-Dec. 8 (4):195-196. [QxMD MEDLINE Link].
Suliman MT. Excision of epidermoid (sebaceous) cyst: description of the operative technique. Plast Reconstr Surg. 2005 Dec. 116(7):2042-3. [QxMD MEDLINE Link].
Lieblich LM, Geronemus RG, Gibbs RC. Use of a biopsy punch for removal of epithelial cysts. J Dermatol Surg Oncol. 1982 Dec. 8(12):1059-62. [QxMD MEDLINE Link].
Mehrabi D, Leonhardt JM, Brodell RT. Removal of keratinous and pilar cysts with the punch incision technique: analysis of surgical outcomes. Dermatol Surg. 2002 Aug. 28(8):673-7. [QxMD MEDLINE Link].
Zuber TJ. Minimal excision technique for epidermoid (sebaceous) cysts. Am Fam Physician. 2002 Apr 1. 65(7):1409-12, 1417-8, 1420. [QxMD MEDLINE Link].
Yang HJ, Yang KC. A new method for facial epidermoid cyst removal with minimal incision. J Eur Acad Dermatol Venereol. 2009 May 3. [QxMD MEDLINE Link].
Tahim A, Ali S, Cheng L. An intra-oral approach to facial skin lumps-a move towards scarless surgery. Oral Maxillofac Surg. 2018 Jun 16. [QxMD MEDLINE Link].
Barclay L. IDSA: skin and soft tissue infections guidelines updated. Medscape Medical News. Available at http://www.medscape.com/viewarticle/827399. Accessed: June 26, 2014.
[Guideline] Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the infectious diseases society of america. Clin Infect Dis. 2014 Jul 15. 59(2):e10-52. [QxMD MEDLINE Link]. [Full Text].
Silver SGHo VCY. Benign epithelial tumors. Freedberg IM, Eisen AZ, Wolff K, et al, eds. Fitzpatrick's Dermatology in General Medicine. 6th ed. New York: McGraw-Hill; 2003. 778-779.

Media Gallery

Unusually large epidermoid cyst with a prominent punctum on the back of a patient. (Ruler is in centimeters.)
Multiple epidermoid cysts on the forehead of a patient with Gardner syndrome.
Cyst containing keratinous material (hematoxylin and eosin, original magnification X1.6).
Higher-magnification view of the cyst wall of the cyst in Media File 3 demonstrates a true epidermis with a granular layer and adjacent laminated keratinous material (hematoxylin and eosin, original magnification X20).

of 4

Author

Linda J Fromm, MD, MA, FAAD Private Practice, Fromm Dermatology at Health Concepts; Dermatologist, Rapid City Medical Center

Linda J Fromm, MD, MA, FAAD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Coauthor(s)

Nathalie C Zeitouni, MDCM, FRCPC Chair of Dermatology, Associate Professor of Dermatology, Roswell Park Cancer Institute

Nathalie C Zeitouni, MDCM, FRCPC is a member of the following medical societies: American Academy of Cosmetic Surgery, American Academy of Dermatology, American College of Mohs Surgery, American Society for Dermatologic Surgery, Women's Dermatologic Society, Royal College of Physicians and Surgeons of Canada

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Former Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Military Dermatologists, Phi Beta Kappa, Texas Dermatological Society

Disclosure: Nothing to disclose.

Christen M Mowad, MD Professor, Department of Dermatology, Geisinger Medical Center

Christen M Mowad, MD is a member of the following medical societies: Alpha Omega Alpha, Noah Worcester Dermatological Society, Pennsylvania Academy of Dermatology, American Academy of Dermatology, Phi Beta Kappa

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Julie C Harper, MD Assistant Program Director, Assistant Professor, Department of Dermatology, University of Alabama at Birmingham

Julie C Harper, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Received honoraria from Stiefel for speaking and teaching; Received honoraria from Allergan for speaking and teaching; Received honoraria from Intendis for speaking and teaching; Received honoraria from Coria for speaking and teaching; Received honoraria from Sanofi-Aventis for speaking and teaching.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors, Kenneth A. Becker, MD, and Isabelle Thomas, MD, to the development and writing of this article.

Epidermal Inclusion Cyst Workup

Laboratory Studies

Imaging Studies

Other Tests

Histologic Findings

References

Tables

Contributor Information and Disclosures

What would you like to print?