Pathogenesis of Pili Annulati

The study on the pathogenesis of pili annulati involved examining plucked scalp hairs and hair roots using various microscopic techniques. It was found that the unique shiny appearance of the hair was due to cortical empty spaces. Transmission electron microscopy revealed small vacuoles, dense bodies, and abnormal spaces in the cytoplasm of differentiating cortical cells, along with large trichohyaline granules. The keratinized cortex of affected hairs had more residual SH groups than controls, suggesting a disorder of protein metabolism. This disorder likely involved partial dysfunction of cytoplasmic ribosomes, leading to inadequate cortical keratin formation.