 FOLDER 16.4 Clinical Correlation: Salivary Gland Tumors chapter 16 Digestive System I SALIVARY G LAN DS 555 Tumors of salivary glands usually occur in the major salivary glands (parotid, submandibular, and sublingual); however, a small percentage occur in the minor glands located within the oral mucosa, palate, uvula, floor of mouth, tongue, pharynx, larynx, and paranasal sinuses. Approxi-mately 80% of salivary gland tumors are benign. Most orig-inate in the parotid gland (Fig. F16.4.1a). The palate is the most common site of minor salivary gland tumors. The most common benign tumor is the pleomorphic adenoma, which accounts for 65% of all salivary gland tu-mors. It is characterized by epithelial tissue containing duc-tal and myoepithelial cells intermingled with areas resembling ground substance of connective tissues (e.g., in cartilage). These connective-like tissues are produced by myoepithelial cells (Fig. F16.4.1b). Most patients with benign tumors present with painless swelling of the involved gland. Because of nerve involvement, signs such as numbness or weakness of innervated muscle are also reported. For instance, paralysis of facial muscles or persistent facial pain may be present in some individuals with parotid tumors. The most common treatment is surgical removal of the tumor. For parotid gland tumors, a total parotidectomy (ex-cision of parotid gland) is often necessary. Postoperative radiation therapy is also used when the tumor is cancer-ous. Complications of surgical treatment of parotid gland tumors include facial nerve dysfunction and Frey’s syn-drome (also known as gustatory sweating). a bb FIGURE F16.4.1 • Pleomorphic adenoma of the parotid gland. a. This photograph shows a patient with a parotid mass located near the angle of the mandible. b. This low magnification photomicrograph shows the features of a pleomorphic adenoma. Note that normal parotid tissue (basophilic-stained areas in upper right) is infiltrated by nodules containing connective-like tissue that resembles the extracellular matrix of cartilage (lighter eosinophilic-stained regions). 120. (From Rubin E, Gorstein F, Schwarting R, Strayer DS. Rubin’s Pathology, 4th ed. Baltimore: Lippincott Williams & Wilkins, 2004, Figs 25–20 and 25–22.)
The lips are the entry point of the alimentary canal. Here, the thin keratinized epithelium of face skin changes to the thick parakeratinized epithelium of the oral mucosa. At the mucocutaneous junction, the red portion of the lips, is characterized by deep pene-tration of connective tissue papillae into the base of the stratified squamous kera-tinized epithelium. The blood vessels and nerve endings in these papillae are responsible for both the color and the exquisite touch sensitivity of the lips. ORIENTATION MICROGRAPH: An H&E–stained sagittal section through the upper lip in this low-power orientation photomicrograph to the right (×8) reveals the skin of the face, the red margin of the lip, and the transition to the oral mucosa (OM). The marked  rectangles indicate representative areas of each of these sites, shown at higher magnifications in upper, middle and lower rows of figures, on the adjacent plate. Note the change in thickness of the epithelium from the exterior or facial portion of the lip (the vertical surface on the right) to the interior surface of the oral cavity (the surface beginning with rectangle marked lower and continuing down the left surface of the lip) in this micrograph. lower OM skin middle top
Keratinized epithelium, lip, human, H&E ×120.