Histogenesis of parotid gland in human fetuses

Background: The present study attempted to find out the histological changes of parotid gland in the developing human fetuses. Materials and Methods: Parotid glands from 60 fresh fetuses of gestational weeks ranging from 12weeks to term were studied after staining with Hematoxylene & Eosin, Masson's Trichome stain, Van Gieson's stain and Verhoeff's stains. Results: The gland of the fetus at 12 weeks composed of solid epithelial cords with occasional canalization, surrounded by loose mesenchyme. Canalization of cords was completed at 25 weeks and adult picture attained at 36 weeks. Division of the glandular parenchyma into lobes and lobules by connective tissue septa started at 17 weeks. A well formed capsule was seen around the gland at 20 weeks. A gradual decrease in intra-glandular connective tissue occurred in late gestational age. Variety of cells such as fibroblasts, mesenchymal cells, fibrocytes and lymphocytes were seen. Numerous adipocytes were found within the glandular parenchyma and around the gland. Ductal tree showed gradual differentiation, presence of cilia-like surface projections from epithelia of larger ducts were seen in 14-32 week fetuses. Conclusion: When compared with various authors, some findings of the present study followed the foot-steps of previous workers whereas some were in contrary, the most important difference being the age of full maturation of the glandular architecture. One of the unique finding being the presence of cilia-like surface projections seen in the larger ducts in 14-32 week aged fetuses.