Inflammatory Seborrheic Keratoses with Mononuclear Cell Infiltration

Abstract

Inflammation in inflammatory seborrheic keratoses [human] was composed of mononuclear cells, particularly lymphocytes. Accumulations of mononuclear cells in the papillary and subpapillary dermis frequently showed no tendency to infiltrate the epithelium. Dramatic interaction of the seborrheic keratosis and the inflammatory process was also common. The lymphocytic exocytosis into the epithelium followed 2 basic patterns: eczematous, characterized by intercellular and intracellular edema, microvesicle formation and epithelial necrosis; and lichenoid, in which a bandlike infiltrate attacked the dermoepidermal junction and hyaline bodies occurred in the infiltrated epithelium and in the dermis. Epithelial changes consisted of necrosis of epithelial cells and related parakeratosis; squamous eddies occasionally were found. Inflammatory cell infiltration in seborrheic keratoses possibly represents a process other than irritation. Mononuclear cell infiltration in seborrheic keratoses may be related to an involutionary process.