Congenital laryngeal atresia. Histopathologic study of two cases.

Two specimens of laryngeal atresia were studied. In the first case stenosis was hard due to noncanalization of the anterior cricoid cartilage. In the second case there was a soft stenosis from limited canalization of the endoluminal soft tissue. Additionally, the first case had a posterior cleft with a persistent pharyngotracheal duct. The stenotic soft-tissue elements in both cases contained striated muscle fibers that interdigitated across the midline. The mucosa on the inferior surface of the hard stenosis was grossly thickened and contained large mucous glands. The embryologic significance of these anomalies is discussed. Presumably these cases represent anomalies caused by different embryologic events.