Cases with a spontaneous regression of an infiltrating non-crateriform keratoacanthoma and squamous cell carcinoma with a keratoacanthoma-like component

J Dermatol. 2014 May;41(5):430-4. doi: 10.1111/1346-8138.12454. Epub 2014 Mar 15.


We herein report the natural course of an early/proliferative stage keratoacanthoma (KA) with infiltrating islands of cytological malignancy (case 1) and a squamous cell carcinoma (SCC) with a KA-like component (case 2), which were observed until their complete regression. The presented case 1 suggests that one of the histopathological forms of KA includes this unusual, infiltrating, non-crateriform architecture, and also indicates the possibility of complete remission in the KA associated with infiltrating islands of cytological malignancy. In the presented case 2, the peripherally-associated KA-like focus was histopathologically considered to be either a remnant of KA focus or verrucous keratosis (hyperplasia). Therefore, the complete spontaneous regression of case 2 suggests that SCC arising in KA still has the potential of spontaneous regression, or that an extremely rare event, namely, the spontaneous regression of (traditional) SCC occurred in the present case.

Keywords: cytological malignancy; keratoacanthoma; non-crateriform; regression; squamous cell carcinoma arising in keratoacanthoma.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / complications
  • Carcinoma, Squamous Cell / pathology*
  • Female
  • Humans
  • Keratoacanthoma / complications
  • Keratoacanthoma / pathology*
  • Keratosis / complications
  • Keratosis / pathology
  • Lip Diseases / complications
  • Lip Diseases / pathology
  • Lip Neoplasms / complications
  • Lip Neoplasms / pathology
  • Neoplasm Regression, Spontaneous / pathology*
  • Skin Diseases / complications
  • Skin Diseases / pathology*
  • Skin Neoplasms / complications
  • Skin Neoplasms / pathology*