History

Keratoacanthoma (KA) typically grows rapidly, attaining 1-2 cm within weeks, followed by a slow involution period lasting up to 1 year and leaving a residual scar if not excised preemptively. Since expedient therapy almost always is instituted, the true natural course of the tumor cannot be confirmed with certainty.

Physical Examination

Pertinent physical findings in keratoacanthoma (KA) are limited to the skin. Lesions typically are solitary and begin as firm, roundish, skin-colored or reddish papules that rapidly progress to dome-shaped nodules with a smooth shiny surface and a central crateriform ulceration or keratin plug that may project like a horn. Most keratoacanthomas occur on sun-exposed areas. The face, neck, and dorsum of the upper extremities are common sites. Truncal lesions are rare. Lesions usually are skin-colored to pinkish-red. Unaffected skin retains its normal appearance. Note the images below.

Keratoacanthoma (squamous cell carcinoma-keratoacanthoma or SCC-KA type) on inner canthus.

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Keratoacanthoma of the left forehead.

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Close-up view of the keratoacanthoma.

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Keratoacanthoma lesion (squamous cell carcinoma-keratoacanthoma or SCC-KA type).

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Differential Diagnoses

Manstein CH, Frauenhoffer CJ, Besden JE. Keratoacanthoma: is it a real entity?. Ann Plast Surg. 1998 May. 40(5):469-72. [QxMD MEDLINE Link].
Gleich T, Chiticariu E, Huber M, Hohl D. Keratoacanthoma: A distinct entity?. Exp Dermatol. 2015 Oct 17. [QxMD MEDLINE Link].
Gibbons M, Ernst A, Patel A, Armbrecht E, Behshad R. Keratoacanthomas: A review of excised specimens. J Am Acad Dermatol. 2019 Jun. 80 (6):1794-1796. [QxMD MEDLINE Link].
Ra SH, Su A, Li X, Zhou J, Cochran AJ, Kulkarni RP, et al. Keratoacanthoma and squamous cell carcinoma are distinct from a molecular perspective. Mod Pathol. 2015 Jun. 28(6):799-806. [QxMD MEDLINE Link].
Kanzaki A, Kudo M, Ansai S, Peng WX, Ishino K, Yamamoto T, et al. Insulin-like growth factor 2 mRNA-binding protein-3 as a marker for distinguishing between cutaneous squamous cell carcinoma and keratoacanthoma. International journal of oncology. 2016 Mar. 48(3):1007-15. [QxMD MEDLINE Link].
Schwartz RA. Keratoacanthoma. J Am Acad Dermatol. 1994 Jan. 30(1):1-19; quiz 20-2. [QxMD MEDLINE Link].
Magalhaes RF, Cruvinel GT, Cintra GF, Cintra ML, Ismael AP, de Moraes AM. Diagnosis and follow-up of keratoacanthoma-like lesions: clinical-histologic study of 43 cases. J Cutan Med Surg. 2008 Jul-Aug. 12(4):163-73. [QxMD MEDLINE Link].
Kossard S, Tan KB, Choy C. Keratoacanthoma and infundibulocystic squamous cell carcinoma. Am J Dermatopathol. 2008 Apr. 30(2):127-34. [QxMD MEDLINE Link].
Cribier B, Asch P, Grosshans E. Differentiating squamous cell carcinoma from keratoacanthoma using histopathological criteria. Is it possible? A study of 296 cases. Dermatology. 1999. 199(3):208-12. [QxMD MEDLINE Link].
Macdonald JB, Macdonald B, Golitz LE, LoRusso P, Sekulic A. Cutaneous adverse effects of targeted therapies: Part II: Inhibitors of intracellular molecular signaling pathways. J Am Acad Dermatol. 2015 Feb. 72 (2):221-36; quiz 237-8. [QxMD MEDLINE Link].
Chuang TY, Reizner GT, Elpern DJ, Stone JL, Farmer ER. Keratoacanthoma in Kauai, Hawaii. The first documented incidence in a defined population. Arch Dermatol. 1993 Mar. 129(3):317-9. [QxMD MEDLINE Link].
Chuang TY, Reizner GT, Elpern DJ, Stone JL, Farmer ER. Squamous cell carcinoma in Kauai, Hawaii. Int J Dermatol. 1995 Jun. 34(6):393-7. [QxMD MEDLINE Link].
Letzel S, Drexler H. Occupationally related tumors in tar refinery workers. J Am Acad Dermatol. 1998 Nov. 39(5 Pt 1):712-20. [QxMD MEDLINE Link].
Miot HA, Miot LD, da Costa AL, Matsuo CY, Stolf HO, Marques ME. Association between solitary keratoacanthoma and cigarette smoking: a case-control study. Dermatol Online J. 2006 Feb 28. 12(2):2. [QxMD MEDLINE Link].
Hsi ED, Svoboda-Newman SM, Stern RA, Nickoloff BJ, Frank TS. Detection of human papillomavirus DNA in keratoacanthomas by polymerase chain reaction. Am J Dermatopathol. 1997 Feb. 19(1):10-5. [QxMD MEDLINE Link].
Lu S, Syrjanen SL, Havu VK, Syrjanen S. Known HPV types have no association with keratoacanthomas. Arch Dermatol Res. 1996 Mar. 288(3):129-32. [QxMD MEDLINE Link].
Wieland U, Scola N, Stolte B, Stucker M, Silling S, Kreuter A. No evidence for a causal role of Merkel cell polyomavirus in keratoacanthoma. J Am Acad Dermatol. 2012 Jul. 67(1):41-6. [QxMD MEDLINE Link].
Alloo A, Garibyan L, LeBoeuf N, et al. Photodynamic therapy for multiple eruptive keratoacanthomas associated with vemurafenib treatment for metastatic melanoma. Arch Dermatol. 2012 Mar. 148(3):363-6. [QxMD MEDLINE Link].
Clausen OP, Beigi M, Bolund L, et al. Keratoacanthomas frequently show chromosomal aberrations as assessed by comparative genomic hybridization. J Invest Dermatol. 2002 Dec. 119(6):1367-72. [QxMD MEDLINE Link].
Kim DK, Kim JY, Kim HT, Han KH, Shon DG. A specific chromosome aberration in a keratoacanthoma. Cancer Genet Cytogenet. 2003 Apr 1. 142(1):70-2. [QxMD MEDLINE Link].
Cabibi D, Conway de Macario E, Ingrao S, Porcasi R, Zucco F, Macario AJ, et al. CD1A-positive cells and HSP60 (HSPD1) levels in keratoacanthoma and squamous cell carcinoma. Cell Stress Chaperones. 2015 Oct 6. [QxMD MEDLINE Link].
Hatta N, Takata A, Ishizawa S, Niida Y. Family with MSH2 mutation presenting with keratoacanthoma and precancerous skin lesions. J Dermatol. 2015 Nov. 42 (11):1087-90. [QxMD MEDLINE Link].
Chuang TY, Reizner GT, Elpern DJ, Stone JL, Farmer ER. Non-melanoma skin cancer and keratoacanthoma in Filipinos: an incidence report from Kauai, Hawaii. Int J Dermatol. 1993 Oct. 32(10):717-8. [QxMD MEDLINE Link].
Reizner GT, Chuang TY, Elpern DJ, Stone JL, Farmer ER. Keratoacanthoma in Japanese Hawaiians in Kauai, Hawaii. Int J Dermatol. 1995 Dec. 34(12):851-3. [QxMD MEDLINE Link].
Reizner GT, Chuang TY, Elpern DJ, Stone JL, Farmer ER. Basal cell carcinoma and keratoacanthoma in Hawaiians: an incidence report. J Am Acad Dermatol. 1993 Nov. 29(5 Pt 1):780-2. [QxMD MEDLINE Link].
Sanders S, Busam KJ, Halpern AC, Nehal KS. Intralesional corticosteroid treatment of multiple eruptive keratoacanthomas: case report and review of a controversial therapy. Dermatol Surg. 2002 Oct. 28(10):954-8. [QxMD MEDLINE Link].
Frank TL, Maguire HC Jr, Greenbaum SS. Multiple painful keratoacanthomas. Int J Dermatol. 1996 Sep. 35(9):648-50. [QxMD MEDLINE Link].
Meffert JJ. Cutaneous sporotrichosis presenting as a keratoacanthoma. Cutis. 1998 Jul. 62(1):37-9. [QxMD MEDLINE Link].
Patel NP, Cervino AL. Treatment of keratoacanthoma: Is intralesional methotrexate an option?. Can J Plastic Surg. Summer 2011. (19)2:e15-8.
Sayama S, Tagami H. Treatment of keratoacanthoma with intralesional bleomycin. Br J Dermatol. 1983 Oct. 109(4):449-52. [QxMD MEDLINE Link].
Annest NM, VanBeek MJ, Arpey CJ, Whitaker DC. Intralesional methotrexate treatment for keratoacanthoma tumors: a retrospective study and review of the literature. J Am Acad Dermatol. 2007 Jun. 56(6):989-93. [QxMD MEDLINE Link].
Goette DK, Odom RB. Successful treatment of keratoacanthoma with intralesional fluorouracil. J Am Acad Dermatol. 1980 Mar. 2 (3):212-6. [QxMD MEDLINE Link].
Goette DK, Odom RB, Arrott JW, Diakon NC, Horn RT Jr. Treatment of keratoacanthoma with topical application of fluorouracil. Arch Dermatol. 1982 May. 118 (5):309-11. [QxMD MEDLINE Link].
Dendorfer M, Oppel T, Wollenberg A, Prinz JC. Topical treatment with imiquimod may induce regression of facial keratoacanthoma. Eur J Dermatol. 2003 Jan-Feb. 13(1):80-2. [QxMD MEDLINE Link].
Grob JJ, Suzini F, Richard MA, et al. Large keratoacanthomas treated with intralesional interferon alfa-2a. J Am Acad Dermatol. 1993 Aug. 29(2 Pt 1):237-41. [QxMD MEDLINE Link].
Canas GC, Robson KJ, Arpey CJ. Persistent keratoacanthoma: challenges in management. Dermatol Surg. 1998 Dec. 24(12):1364-9. [QxMD MEDLINE Link].

Media Gallery

Keratoacanthoma (squamous cell carcinoma-keratoacanthoma or SCC-KA type) on inner canthus.
Keratoacanthoma of the left forehead.
Close-up view of the keratoacanthoma.
Keratoacanthoma lesion (squamous cell carcinoma-keratoacanthoma or SCC-KA type).

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Author

Tsu-Yi Chuang, MD, MPH, FAAD Clinical Professor, Department of Dermatology, Keck School of Medicine of the University of Southern California; Dermatologist, HealthCare Partners

Tsu-Yi Chuang, MD, MPH, FAAD is a member of the following medical societies: American Academy of Dermatology, American Society for Dermatologic Surgery, International Society of Dermatology

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Steven R Feldman, MD, PhD Professor, Departments of Dermatology, Pathology and Public Health Sciences, and Molecular Medicine and Translational Science, Wake Forest Baptist Health; Director, Center for Dermatology Research, Director of Industry Relations, Department of Dermatology, Wake Forest University School of Medicine

Steven R Feldman, MD, PhD is a member of the following medical societies: American Academy of Dermatology, American Society of Dermatopathology, North Carolina Medical Society, Society for Investigative Dermatology

Disclosure: Received honoraria from Amgen for consulting; Received honoraria from Abbvie for consulting; Received honoraria from Galderma for speaking and teaching; Received consulting fee from Lilly for consulting; Received ownership interest from www.DrScore.com for management position; Received ownership interest from Causa Reseasrch for management position; Received grant/research funds from Janssen for consulting; Received honoraria from Pfizer for speaking and teaching; Received consulting fee from No.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Received income in an amount equal to or greater than $250 from: Elsevier; WebMD<br/>Served as a speaker for various universities, dermatology societies, and dermatology departments.

Additional Contributors

Ryan Brashear, MD Staff Physician, Department of Dermatology, Indiana University School of Medicine

Ryan Brashear, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association

Disclosure: Nothing to disclose.

Arash Taheri, MD Research Fellow, Center for Dermatology Research, Department of Dermatology, Wake Forest University School of Medicine

Disclosure: Nothing to disclose.

Keratoacanthoma Clinical Presentation

History

Physical Examination

References

Tables

Contributor Information and Disclosures

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