Pathology of the Salivary Glands Flashcards
What is the pattern of salivary flow within the salivary glands?
Acini and intercalated ducts are surrounded by myoepithelial cells
Myoepithelial cells contract, acini release secretions into intercalated ducts
Intercalated ducts drain into striated ducts, which drain into interlobular ducts, before slowly transitioning into main ducts which empty into mouth
What is the function of a serous vs a mucinous acini?
Serous - Secrete proteins - i.e. lysozymes, secretory IgA, amylase
Mucinous - mostly lubrication
What is the composition of the three main salivary glands?
Parotid - mostly serous acini
Submandibular - mixture of serous and mucinous acini, serous slightly more
Sublingual - Mainly mucinous acini
What is sialadenitis and what typically causes it?
Acute or chronic inflammation of the salivary gland
Parotid glands - often viral infection like mumps or HIV
Bacteria - i.e. Staph aureus, can cause or complicate it by filling it with pus
Autoimmune disorders like Sjogren’s syndrome may cause it
What are the complications of siladenitis?
Decreased saliva production -> xerostomia. Causes caries, fissures, and dysphgaia
Sialolithiasis - a cause and a complication of salivary gland ductal obstruction -> usually submandibular duct
What is a mucocele?
Trauma-induced leakage of mucinous salivary gland secretions into surrounding connective tissue stroma -> forms a pseudocyst which worsens with inflammation and granulation tissue formation
What are the trends with frequency of neoplasms in the salivary glands / chance of being malignant?
Frequency - highest number of neoplasms in parotid gland
Malignancy - if you have a mass in a salivary gland, it is much more likely to be malignant in small glands (sublingual or minor salivary)
What is the most common salivary gland tumor? Where is it thought to arise from histologically?
Pleomorphic adenoma - benign mixed tumor
Arises from intercalated ductal reserve cells or myoepithelial cells
Makes sense because the tumor is actually heterogenous
What are the clinical features of pleomorphic adenoma and what is its most common problem?
Painless, slowing-growing mass usually in parotid gland
Treatment is possible with complete surgical excision, but margins are so irregular that the surgeon can miss some and it will come back
Mass is nodular and appears generally well circumscribed, but the surgeon must take a generous margin
How does pleomorphic adenoma appear microscopically?
Heterogenous mixture of epithelial and mesenchymal tissues with no atypia.
Epithelial component - tubules, glands, cords, or nests
Stromal areas - myxoid, fibrous, cartilaginous, or even osseous
What is the uncommon complication of pleomorphic adenoma? How does this present?
Carcinoma can arise within it, and it is an aggressive malignancy
Will present with signs of a facial nerve palsy if in parotid gland, as it is neurotropic (similar to how pancreatic adenocarcinoma is)
What is a Warthin tumor and who gets it?
Papillary Cystadenoma Lymphomatosum
Always arises in the parotid gland in male smokers
How does Warthin tumor appear grossly and microscopically?
Grossly - benign cystic tumor
Microscopically - Cystic spaces with tall pink columnar epithelial cells with abundant eosinophilic cytoplasm (arise from striated ducts). They produce chemoattractants so there will be a dense lymphoid stroma underneath which looks like germinal centers
(lymph-node-like stroma)
What is the most common malignant primary salivary gland neoplasm and what cell types are associated?
Mucoepidermoid carcinoma
-> Associated with dysplastic squamous and mucinous cells
What determines the prognosis of mucoepidermoid carcinoma?
Low-grade - good prognosis, defined by well-differentiated mucinous glandular cells and cystic configurations
High grade - squamous cells in nests predominate, with high mitotic rate and focal necrosis
