Embryology and Developmental Disorders

Embryology of the salivary glands is driven by the complex interactions between the epithelial cells, which will eventually give rise to the acini and the ductal system, and the surrounding mesenchyme, which will provide the gland capsule. Agenesis may be partial or total, unilateral or bilateral, and may involve more than one salivary gland. Association with “specific syndromes” such as Levy–Hollister syndrome, Down syndrome, or Klinefelter syndrome has been reported. Tumor-like presentations of maldevelopment include rare hamartomas of the hard palate and unusual cystic choristomas of the submandibular gland. The congenital salivary gland anlage tumor or congenital pleomorphic adenoma is thought to represent a hamartoma of minor salivary gland origin. This chapter describes the embryology of the major salivary glands and addresses their developmental disorders, including heterotopic salivary glands, aplasia (absence), gland duplication, and congenitally atretic, imperforate, ectatic, and duplicated ducts.