Lacrimal sac dacryoliths (86 samples): chemical and mineralogic analyses.

Background: Because dacryoliths occur at low frequency, few studies have focused on their composition. We aimed to present findings from morphological, chemical, and mineralogic analysis of 86 dacryoliths. Methods: We studied 86 dacryoliths obtained during 832 dacryocystorhinostomies (DCR) performed for postsaccal obstruction. We examined the samples with atomic infrared spectrometry (80 samples), amino acid analysis (17 samples), scanning electron microscopy, and an electron microprobe with an energy dispersive detector (seven samples). Results: Dacryoliths were found in 86/832 DCRs (10.3 %), mostly in patients with primary acquired nasolacrimal duct obstruction. All the dacryoliths were soft, composed of organic material, including proteins and mucoproteins, with approximately 20 % amino acid content. There were no 'hard' dacryoliths composed of calcium phosphate. The stones were composed of lobes and lobules built on an amorphous core material with small cavities, probably as a result of various chemical processes that produced a gaseous product. The most frequent elements found in inorganic inclusions were silicon, magnesium, sulfur, potassium, calcium, sodium, and chlorine. Also, some particles had high contents of bismuth, titanium, iron, and organic fibers. The fibers found in the core of dacryoliths suggested a potential origin from cotton swabs used in cosmetics. Conclusion: Dacryoliths are composed almost exclusively of organic material, including proteins and mucoproteins, with approximately 20 % amino acid content. [ABSTRACT FROM AUTHOR]