Keratoacanthoma arising in nevus comedonicus

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Nevus comedonicus is a rare, benign hamartoma of the pilosebaceous unit, classified as a subtype of epidermal nevus.
• First described in 1895, it clinically presents as closely grouped, dilated follicular openings filled with keratin plugs, resembling comedones.

Observation:

• The case involves extensive nevus comedonicus, a condition rarely associated with malignant changes.
• A specific observation is the development of keratoacanthoma within this extensive nevus comedonicus.

Findings:

• Malignant degeneration of nevus comedonicus is exceptionally rare.
• This report documents a unique instance of keratoacanthoma arising within a large nevus comedonicus.

Implications:

• This case underscores the importance of monitoring extensive nevus comedonicus for potential malignant transformation.
• It suggests that while rare, the risk of developing squamous cell carcinoma, such as keratoacanthoma, should be considered in the differential diagnosis of evolving lesions within nevus comedonicus.
• Further research may be warranted to understand the specific factors contributing to malignant degeneration in nevus comedonicus.