Hair Follicle Nevus With Features of Comedo Nevus: An Expanding Spectrum

A congenital accessory skin appendage of the nasal columella and nostril sill: a rare anatomical variation

PURPOSE

An accessory skin appendage of the nasal columella and nostril sill is an extremely rare congenital anatomical malformation; only a single case has been reported in the literature. However, no pathophysiology has been proposed. The purpose of this study is to present a review of the anatomical distribution of accessory skin appendages and provide a comprehensive review of their pathophysiology based on embryological development.

METHODS

We present four cases of a protruding skin appendage of the nasal columella or nostril sill. All lesions were present from birth with no family history of skin appendages. Three patients underwent surgical excision under local anesthesia.

RESULTS

The lesions were located at the upper and lower lateral borders of the nasal columella and the medial and lateral borders of the nostril sill. There has been no sign of recurrence over a mean follow-up of 11 months.

CONCLUSIONS

Any obstacle or injury during the migration process of embryonic development may result in maldevelopment. If an obstacle or injury occurs during the medial migration of the medial nasal process, congenital polypoid remnant tissue may remain along the migration route, resulting in an accessory skin appendage of the nasal columella. The location of the accessory columellas ranged from the nostril sill to the soft triangle along the anterior border of the medial crus of the alar cartilage. These anatomical distributions correspond exactly to the migration route of the medial nasal process during embryonic development. We believe that it supports our suggested pathophysiology.