Funding sources: none.
Keratoacanthoma and other types of squamous cell carcinoma with crateriform architecture: Classification and identification
Version of Record online: 18 FEB 2013
© 2013 Japanese Dermatological Association
The Journal of Dermatology
Volume 40, Issue 6, pages 443–452, June 2013
How to Cite
Misago, N., Inoue, T., Koba, S. and Narisawa, Y. (2013), Keratoacanthoma and other types of squamous cell carcinoma with crateriform architecture: Classification and identification. The Journal of Dermatology, 40: 443–452. doi: 10.1111/1346-8138.12104
Conflicts of interest: none.
- Issue online: 4 JUN 2013
- Version of Record online: 18 FEB 2013
- Manuscript Accepted: 6 JAN 2013
- Manuscript Received: 25 NOV 2012
- crateriform squamous cell carcinoma;
- infundibular squamous cell carcinoma;
- keratoacanthoma with malignant transformation;
- keratoacanthoma-like squamous cell carcinoma
The terminology and classification of keratoacanthoma (KA) and other types of squamous cell carcinoma (SCC) with crateriform architecture have not been clarified. The study evaluated the clinicopathological features of 41 nodular (exo-endophytic) SCC lesions with a central keratin-filled crater, including KA (well-developed stage). The lesions were histopathologically classified into six categories: (i) KA (well-developed stage) (27 lesions); (ii) KA-like SCC (three lesions); (iii) KA with malignant transformation (three lesions); (iv) infundibular SCC (crateriform) (four lesions); (v) crateriform SCC arisen from actinic keratosis (three lesions); and (vi) crateriform Bowen's disease (one lesion). The true characteristics of KA-like SCC remain unresolved, but there are three possibilities, namely, that it is one step in the evolution of KA, it is a borderline lesion between KA and invasive SCC, or it is one form of “KA with malignant transformation”. KA, KA-like SCC, KA with malignant transformation and infundibular SCC (crater form) are considered to be hair follicle-related neoplasms. In contrast, crateriform SCC arisen from actinic keratosis and crateriform Bowen's disease are SCC, which are not related either to the hair follicles or KA. From an etiological standpoint, the presented lesions in these six categories are considered to be mixed up due to the similarity of crateriform architecture between the various types of lesions. However, the information provided in this report is intended to help physicians to make an accurate differential diagnosis of these conditions in clinical practice. The present study provides an opportunity to standardize the terminology for KA and related neoplasms.