Seborrheic keratoses and trichostasis spinulosa

Area of Science:

• Dermatopathology
• Histology

Background:

• Seborrheic keratosis (SK) is a common benign epidermal tumor.
• Trichostasis spinulosa (TS) is characterized by the presence of vellus hair within the infundibulum.

Purpose of the Study:

• To investigate the presence and significance of trichostasis spinulosa in seborrheic keratoses.
• To explore the potential follicular origin of seborrheic keratoses.

Main Methods:

• Histopathological examination of 325 seborrheic keratosis samples.
• Assessment for the presence of trichostasis spinulosa within the lesions and adjacent structures.

Main Results:

• Trichostasis spinulosa was identified in 54 out of 325 (16.6%) seborrheic keratoses.
• TS was observed within keratinous cysts and between papillomatous surface keratin, as well as in contiguous hair follicles.
• Both TS and trichostasis in SK were more frequent in older age groups.

Conclusions:

• Trichostasis spinulosa is a frequent finding in seborrheic keratoses.
• The presence of TS suggests that seborrheic keratoses may incorporate and originate from the infundibular portion of hair follicles.
• TS serves as a marker for vellus hair follicles in the context of seborrheic keratosis development.