Congenital Nostril Stenosis with a Horseshoe-like Shape.

We report a rare case of congenital nostril stenosis because it is very interesting from the perspective of human embryo development. As we were not able to find a similar congenital case in the literature, we would like to describe it here. The patient is a 36-year-old woman who had bilateral congenital stenotic nostrils with horseshoe-like shape. Particularly, the bilateral medial crura protruded prominently. When she inhaled strongly, she could not breathe further because the action was analogous to the closure of a valve. Her elder sister had similar stenosis in the right nostril only, and parents did not have any stenotic nostrils. During the surgery, the prominent webs of the bilateral medial crura were resected, and Y-V advancement flap was inserted bilaterally to avoid restenosis. Histopathological examination revealed that the resected tissue contained cartilaginous and muscular tissue. A Koken retainer was worn throughout each entire day without washing the face or taking a bath for 3 months after surgery and was washed for keeping hygiene many times every day. After surgery, the patient can breathe well when she inhales strongly and is very satisfied with the operative results. Stenosis has not recurred 6 months after operation. Pathogenesis of this case is thought to occur at the early phase of embryo development when the medial and lateral nasal placodes form a downward-facing "horseshoe."