Morphologic study of multilamellar bodies in the surface layer of sialolith

Fixation by adding tannic acid to ordinary aldehyde solution has been reported to be a useful means for the ultramicroscopic visualization of phospholipids.Sialolithiasis is a common disorder of the salivary glands. Although the mechanism of calcifying sialoliths remains to be elucidated, it was reported that biochemically sialoliths contain a lipidenriched matrix. The lipids in this matrix are associated with mineral deposition in sialoliths. Therefore, using an ultramicroscope with a fixative containing tannic acid we examined human sialoliths to ascertain whether the phospholipids contained in the siaoliths are related histologically to the mechanism of mineralization.Multilamellar bodies (MLB) were found in the surface layer of the sialoliths. MLBs were composed of alternating dark and light layers and their cycle length measured about 4-6 nm (approximately 5 nm). Morphological characteristics of MLBs are similar to the lamellar bodies in pulmonary surfactant. These MLBs clearly represented phospholipids and the view that phospholipids are involved in mineralization in sialoliths was supported by these histologic findings.