Keratoacanthoma clinical behavior: a systematic review

Area of Science:

• Dermatology
• Pathology
• Oncology

Background:

• Keratoacanthomas (KAs) have been controversially classified as either benign or malignant.
• Some researchers assert KAs are a form of squamous cell carcinoma (SCC).
• Lack of clear diagnostic criteria and understanding of KA etiology complicates classification.

Purpose of the Study:

• To investigate the biologic behavior and metastatic potential of keratoacanthomas.
• To compare the clinical outcomes of KAs with those of squamous cell carcinoma (SCC).
• To clarify the classification of KAs as benign or malignant entities.

Main Methods:

• Systematic review and data extraction from 113 published articles.
• Analysis of 445 cases of keratoacanthoma with reported follow-up and outcomes.
• Comparative analysis with 429 reported cases of skin squamous cell carcinoma (SCC).

Main Results:

• None of the 445 reviewed keratoacanthoma cases resulted in death or distant metastases.
• In contrast, 61 cases of squamous cell carcinoma (SCC) showed metastases, and 24 deaths were directly attributed to SCC.
• The distinct clinical behaviors differentiate KAs from SCC.

Conclusions:

• Keratoacanthomas exhibit benign biologic behavior.
• KAs are distinct epidermal growths and not a malignant variant of squamous cell carcinoma (SCC).
• The findings support the classification of KAs as benign lesions.