Inflammatory seborrheic keratoses with mononuclear cell infiltration.

Area of Science:

• Dermatopathology
• Immunohistochemistry
• Skin Biology

Background:

• Seborrheic keratosis (SK) is a common benign epidermal tumor.
• Inflammatory variants of SK present unique histopathological features.
• Understanding the inflammatory infiltrate is key to differentiating SK subtypes and potential underlying processes.

Purpose of the Study:

• To characterize the inflammatory infiltrate in inflammatory seborrheic keratoses.
• To investigate the patterns of lymphocytic interaction with the epithelium.
• To explore the potential implications of this inflammation beyond simple irritation.

Main Methods:

• Histopathological examination of inflammatory seborrheic keratosis lesions.
• Analysis of mononuclear cell distribution and infiltration patterns.
• Identification of specific epithelial changes associated with inflammation.

Main Results:

• Inflammation predominantly composed of mononuclear cells, especially lymphocytes.
• Lymphocytic infiltration often localized to the dermis without significant epithelial invasion.
• Two distinct patterns of lymphocytic exocytosis into the epithelium: eczematous and lichenoid.
• Observed epithelial changes included necrosis and parakeratosis.
• Squamous eddies were occasionally noted.

Conclusions:

• The mononuclear cell infiltrate in inflammatory seborrheic keratoses may indicate an involutionary process.
• The observed patterns suggest a complex interaction between the tumor and the immune system.
• Inflammation in these lesions likely represents a biological process distinct from mere irritation.