Salivary Gland Pathology Thomas Rosenzweig, MD

Xerostomia Xerostomia is defined as a dry mouth resulting from a decrease in the production of saliva Seen in Sjögren syndrome Sialadenitis of the salivary glands is also seen Involvement of the lacrimal glands in Sjögren syndrome may also produce dry eyes—keratoconjunctivitis sicca. Seen in radiation therapy

Sialadenitis (salivary gland inflammation) Mucoceles most common inflammatory salivary gland lesion lower lip Trauma causes blockage or rupture of a salivary gland duct, with leakage of saliva into the surrounding tissue toddlers, young adults, and the elderly (falling trauma) swellings of the lower lip (blue translucent hue) Pseu­docysts cyst-like spaces (filled with mucin and mɸ) lined by inflammatory granulation tissue or by fibrous connective tissue Mumps most common viral sialadenitis Affects major salivary glands, particularly the parotids Ranula epithelial-lined cysts when the duct of the sublingual gland is damaged “Plunging ranula” - a ranula so big it goes through the tissue connecting the two bellies of the mylohyoid muscle Nonspecific bacterial sialadenitis S. aureus and Streptococcus viridans submandibular glands Unilateral involvement of a single gland usually secondary to ductal obstruction produced by stones (sialolithiasis)

Salivary Gland Neoplasms Parotid Gland Most of the tumors Likely benign Often appear in the fifth to seventh decades of life Sublingual Gland Fewest tumors Likely malignant Often appear somewhat later

Pleomorphic Adenoma Most common benign tumor in the parotid gland Painless, slow-growing, mobile, discrete round masses PLAG1 is overexpressed Gray-white myxoid AND blue translucent areas of chondroid tissue Called mixed tumors show both epithelial and mesenchymal differentiation ductal (epithelial) AND myoepithelial (mesenchymal) cells Heterogeneity of the tumor = dominant histologic feature arranged in duct formations, acini, tubules, strands, or sheets typically dispersed within a mesenchyme-like background Carcinoma ex pleomorphic adenoma A carcinoma arising IN a pleomorphic adenoma most aggressive of all salivary gland malignant neoplasms

Warthin Tumor (Papillary Cystadenoma Lymphomatosum) Second most common salivary gland tumor Round-oval encapsulated masses (2 to 5 cm in diameter) Parotid gland only - Benign 50-70 year old smoking males When cut open: pale gray surface with narrow spaces filled with serous secretions spaces are lined by a double layer of neoplastic epithelial cells resting on a dense lymphoid stroma

Mucoepidermoid Carcinoma most common primary malignant tumor of the salivary glands mixtures of squamous and mucus cells t(11;19) (q21;p13) translocation that creates a gene with MECT1 and MAML2 parts When cut open: pale gray surface with mucin-filled spaces Low-grade rarely metastasize (may invade) 5-year survival rate = 90% High-grade metastasize (invasive) 5-year survival = 50%

Adenoid Cystic Carcinoma Small cells with dark, compact nuclei and little cytoplasm Minor salivary glands Palatine gland Most are here (50%) Major salivary glands Parotid and Submandibular glands Tendency to invade perineural spaces Very recurrent Eventually, 50% or more metastasize to other sites (bone, liver, and brain)

Salivary Gland Pathology