Trichilemmal keratinization in seborrheic keratoses

Area of Science:

• Dermatopathology
• Histology
• Keratinization

Background:

• Seborrheic keratoses are common benign skin tumors.
• The histological features of seborrheic keratoses are well-documented.
• Trichilemmal keratinization (TK) is a specific type of keratinization typically seen in hair follicles.

Purpose of the Study:

• To investigate the occurrence and characteristics of trichilemmal keratinization (TK)-like changes in seborrheic keratoses.
• To determine if TK or TK-like keratinization correlates with specific clinical or histological features of seborrheic keratoses.

Main Methods:

• Histological review of 112 cases of seborrheic keratoses.
• Identification and characterization of keratinization patterns.
• Correlation of TK-like changes with clinical presentation (pruritus) and location (extremities).
• Analysis of association with inflammatory signs and histological subtypes.

Main Results:

• A TK-like keratinization process was observed in 33 out of 112 (29.5%) seborrheic keratoses.
• This keratinization was more frequent in pruritic lesions and those on the extremities.
• Histologically, the changes were found in pseudocysts and crypts, often in inflamed areas.
• No significant relationship was found between TK-like changes and the specific histological types of seborrheic keratoses.

Conclusions:

• A histological process indistinguishable from trichilemmal keratinization (TK) can frequently occur in seborrheic keratoses.
• Inflammation appears to be a significant factor in inducing these TK-like changes.
• The presence of TK-like keratinization in seborrheic keratoses is likely a reactive phenomenon rather than a primary feature.