Keratoacanthoma: Update on the Debate.

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Keratoacanthoma (KA) is a common cutaneous tumor characterized by rapid growth followed by spontaneous involution.
• KA typically affects sun-exposed skin and has numerous potential causative associations, including certain therapeutic agents.
• The classification of KA remains contentious, with ongoing debate regarding its relationship to squamous cell carcinoma (SCC).

Purpose of the Study:

• To review the current understanding of Keratoacanthoma (KA) and its relationship with Squamous Cell Carcinoma (SCC).
• To explore the reasons for inconsistent reporting and diagnosis between KA and SCC.
• To highlight genetic and pathogenetic differences and similarities between KA and SCC.

Main Methods:

• Review of existing literature on Keratoacanthoma (KA) and Squamous Cell Carcinoma (SCC).
• Analysis of microscopic criteria and clinical behavior of KA.
• Examination of genetic studies and pathogenetic factors, including apoptotic pathways and viral involvement.

Main Results:

• Inconsistent reporting of KA versus SCC is attributed to overlapping microscopic features, aggressive KA variants, and potential medicolegal factors.
• Genetic studies reveal distinctions between KA and SCC, with evidence of activated apoptotic pathways in KA.
• Human polyomavirus 6 is implicated in the pathogenesis of some KA cases.

Conclusions:

• Keratoacanthoma (KA) can be considered a low-grade variant of Squamous Cell Carcinoma (SCC) due to overlapping features and some shared genetic underpinnings.
• Despite similarities, distinct genetic differences and pathogenetic factors support a nuanced classification.
• Accurate differentiation between KA and SCC is crucial for appropriate patient management and treatment strategies.