New insights into the pathophysiology of primary acquired dacryostenosis.

Objective: To obtain new insights into the pathophysiology of primary acquired dacryostenosis.

Design: Comparative autopsy tissue study with histopathologic correlations.

Materials: Tissue specimens from the human nasolacrimal ducts of 36 patients undergoing endonasal dacryocystorhinostomy within a framework of primary acquired dacryostenosis were analyzed by histologic studies and electron microscopic examination. Six lacrimal systems of body donors served as controls.

Testing: One group of tissue specimens from each lacrimal system was prepared and processed with paraffin, sectioned, stained by different methods, and finally examined by light microscopy. The other group was processed with araldite after preparation, sectioned semithin and ultrathin, and examined by transmission electron microscopy.

Main Outcome Measures: The degree of dacryostenosis was scored in each tissue specimen by grading the histologic sections as mild (active chronic inflammation), moderate (proliferative sclerotic forms of chronic fibrosis), or severe (total subepithelial fibrosis).

Results: Of 36 patients with epiphora, 13 had functional obstruction with a patent lacrimal system on syringing; in 23 cases, the lacrimal passage was completely obstructed. Different pathologic stages correlating to duration of symptoms were found ranging from active chronic inflammation to proliferative sclerotic forms and total subepithelial fibrosis.

Conclusions: Descending inflammation from the eye or ascending inflammation from the nose initiates swelling of the mucous membrane, remodeling of the helical arrangement of connective tissue fibers, malfunctions in the subepithelial cavernous body with reactive hyperemia, and temporary occlusion of the lacrimal passage. In the follow-up, repeated isolated occurrence of dacryocystitis leads to structural epithelial and subepithelial changes, which may lead either to a total fibrous closure of the lumen of the efferent tear duct or to a nonfunctional segment in the lacrimal passage that is manifest on syringing.