Abstract: Seborrheic keratosis (SK) is a common benign epidermal tumor that predominantly affects adults and is exceptionally rare in children with its pathogenesis not yet fully elucidated. Recent studies have reported that colonization by microorganisms, particularly Malassezia spp, may be implicated in the development of SK. Herein, we report a case of SK in a child complicated with Malassezia colonization. The patient was an 11-year-old girl presenting with two black verrucous plaques on the lumbar region that had gradually enlarged over four years. Dermoscopy revealed cerebriform structures with comedo-like openings. Histopathological examination demonstrated hyperkeratosis and pseudohorn cysts, and PAS staining detected abundant Malassezia within the stratum corneum.

Key words: seborrheic keratosis, Malassezia, pediatric dermatology, keratinization disorders, hyperkeratosis