Consecutive microscopic anatomical characteristics of the lacrimal sac and nasolacrimal duct: cases with or without inflammation.

PURPOSE

We examined the consecutive microscopic anatomy of the lacrimal sac and nasolacrimal duct with or without conspicuous inflammation.

METHODS

We used 18 postmortem lacrimal sacs and nasolacrimal ducts of 12 Japanese subjects (5 males, 7 females, aged 75-98 years at death). The removed mucosal wall was transversely sectioned. The first slice was cut around the internal canalicular punctum, the second slice was at the superior opening of the bony nasolacrimal canal, and the other four were harvested from the nasolacrimal duct. All specimens were dehydrated and embedded in paraffin, cut into 7-μm thick sections, and stained with Masson's trichrome.

RESULTS

The lumen was larger in the lacrimal sac than in the nasolacrimal duct. The lacrimal sac wall was less developed than the nasolacrimal duct wall. All specimens but two showed a narrowed area in the nasolacrimal duct. Specimens without conspicuous inflammation showed some subepithelial inflammatory cell infiltration. Goblet cells were smaller in number in the lacrimal sac with an increasing tendency in the inferior direction. Specimens with conspicuous inflammation showed narrowed portions in the nasolacrimal duct, in which severe inflammation and exudate in the lumen was observed. The epithelium was denuded and goblet cells were lost. A specimen with focal inflammation illustrated similar findings in the inflammatory part, but the other parts were similar to the specimens without inflammation.

CONCLUSIONS

Consecutive microscopic anatomical characteristics of the lacrimal sac and nasolacrimal duct were different from each other. A narrowed part of the nasolacrimal duct lumen is speculated to be a risk for obstruction.