Congenital lower nasolacrimal duct anomaly: a case report.

A congenital anomaly of the nasolacrimal system not previously described is reported. The apposition of the distal end of the nasolacrimal duct was not with the nasal cavity as normally occurs prior to birth but to the external skin. As a result the child presented with difficulty with tear drainage and consequent infection--"neonatal conjunctivitis" followed by a facial abscess at the left lower border of the nose. Recent embryological studies suggest that this anomaly is due to failure of complete separation and migration of the epithelial rod most distal from the surface ectoderm to the inferior meatus of the nasal cavity. This distal remnant of the nasolacrimal duct thus remains juxtaposed to the surface ectoderm of the face on the lateral aspect of the alar nares. The modern concept of the embryological development of the nasolacrimal system is reviewed.