MICROLITHIASIS IN PAROTID SIALADENOSIS AND CHRONIC SUBMANDIBULAR SIALADENITIS IS RELATED TO THE MICROENVIRONMENT - AN ULTRASTRUCTURAL AND MICROANALYTICAL INVESTIGATION

Aims: Microlithiasis was investigated in parotid sialadenosis and chro nic submandibular sialadenitis to determine if it relates to the gland ular microenvironment as has been found experimentally. Methods and re sults: Semithin sections were stained by a mixture of methylene blue a nd Azure II followed by basic fuchsin, which stains calcified parts of microliths red and organic parts green, and ultrathin sections were e xamined electron microscopically and micro-analytically. Microliths in sialadenosis were found in periacinar stroma, in which necrotic acina r cells were found, and in parenchyma, and consisted of consolidated o rganic material with little or no crystalline calcium. Microliths in s ialadenitis were found in stroma, particularly around intercalary duct s, in lumina and in parenchyma, and contained much crystalline calcium . Macrophages enclosed some microliths. Conclusions: The paucity of ca lcium in microliths in sialadenosis and the abundance in sialadenitis relates to the glandular calcium. The periacinar distribution of micro liths in sialadenosis possibly relates to formation in periacinar necr otic debris. The distribution of microliths in sialadenitis around int ercalary ducts possibly relates to formation in matrix vesicles formed from atrophic parenchyma, and in lumina to formation in stagnant secr etory material. Microliths appear to be scavenged by macrophages. Thus the experimental finding that salivary microlithiasis relates to the microenvironment pertaining in humans.