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Salivary Gland IllnessThe non-cancerous salivary gland diseases represent a disparate group of disorders affecting both the major and minor salivary glands. They range from inflammatory disorders of infectious or autoimmune etiology to obstructive and idiopathic disorders. The major salivary glands are most often involved, and many of these salivary gland problems are associated with the presence of other systemic diseases. A thorough history and physical examination is typically adequate to recognize and differentiate this group of conditions and can make elaborate diagnostic evaluations unnecessary. Many of the granulomatous, autoimmune and idiopathic salivary problems have medical solution and will not be dealt with further here. We will instead make greater mention of those problems for which the special skills of the head and neck surgeon are more often sought.
Therapy is initially conservative employing hydration, sialogogues, heat, massage of the affected gland, and intravenous antibiotic. If improvement is not seen within the first 24 to 48 hours, operative intervention may be indicated. Chronic sialadenitis Decreased salivary flow with stasis is a key factor in chronic sialadenitis.The condition is more common in the parotid gland and it is often associated with a previous episode of acute suppurative inflammation. With chronic inflammation, alterations in salivary chemistry and enzyme and immunoglobulin content take place. Symptoms include recurrent mildly painful swelling of the parotid which often accompany eating and most patients experience permanent dry mouth ("xerostomia"). Treatment is initially similar to that for acute sialadenitis and a thorough search is made for treatable predisposing factors such as stones (see below). If conservative measures fail, ductal dilatation, ligation of the duct, irradiation or surgical removal of the gland may be performed. Obstructive Disorders Mucoceles and Mucous Retention Cysts Mucoceles and mucous retention cysts usually involve the minor salivary glands of the lower lip, cheek lining or floor of the mouth. Mucoceles lack an epithelial lining and are therefore not true cysts. They likely result from ductal obstruction or trauma and accumulation of mucus in tissues. Mucous retention cysts do have a true epithelial lining. The "ranula"
( "frog's belly") is a mucous retention cyst Salivary Stones ("Sialolithiasis") Most salivary gland stones ("calculi") occurs in the submandibular gland (80 to 90%)with the parotid gland being home to the remaining 10 to 20%. Serum calcium and phosphorous levels have no known correlation with the stone formation. Calculi may be found within the ductal system or the salivary gland itself. In most cases a single calculus is involved. Stone formation occurs via the deposition of calcium phosphate and an organic matrix of carbohydrates and amino acids about a nidus of debris or other material. If the stone produces ductal obstruction ,blockage of saliva flow will occur with development of inflammation and possible ascending bacterial infection. Streptococcus viridans is a common offending bacterium. Stone formation most often occurs in middle-aged males and can produce intermittent salivary gland swelling and discomfort, especially with eating. Calculi can lead to the development of chronic sialadenitis (as noted above) and may also lead to an episode of acute suppurative sialadenitis. Diagnosis: When complicated by acute infection, mucopurulent material may be expressed from the duct with massage of the gland. X-rays (e.g. submentovertex or occlusal films) are sometimes useful in the diagnosis and location of calculi. 90% of submandibular calculi are "radiopaque" (show up on xray), but 90% of parotid calculi are "radiolucent" and don't appear. Sialography is very accurate in the diagnosis of salivary stones. It involves the injection of dye into the salivary duct, followed by xray of the area, (see image above). Some smaller stones may pass spontaneously with appropriate conservative management including hydration, sialogogues, heat, massage, and appropriate antibiotics. Surgical stone removal may be performed through an incision in the oral cheek lining for calculi located found distally in the duct. However, calculi located near the hilum of the gland often require complete excision of the involved gland. Benign Salivary Tumors Tumors of the salivary glands are uncommon, representing just 2-4% of head and neck neoplasms.Tumors of the parotid gland are the most common and are 5 times more common than tumors of the minor salivary glands. The latter, though, are almost twice as common as tumors in the submandibular gland. The most common benign tumor is the benign mixed tumor, or "pleomorphic adenoma." Although etiology for these tumors is unknown, environmental and genetic factors have been suggested. Radiation exposure has been linked to the development of the benign Warthin tumor and to the malignant mucoepidermoid carcinoma, while Epstein-Barr virus may be a factor in the development of lymphoepithelial tumors. The classic presentation of a benign salivary gland tumors is a painless, slow-growing mass on the face (parotid), angle of the jaw (parotid tail, submandibular), or neck (submandibular), or a swelling at the floor of the mouth (sublingual gland). Benign tumors are almost always mobile, and (for masses of the parotid gland),do not affect the function of the facial nerve. Pleomorphic Adenoma ("benign mixed tumor") Pleomorphic adenomas are the most common tumors of the salivary glands and are most commonly found in the tail of the parotid gland. If found in the minor salivary glands, the hard palate is most frequently involved. These are called "pleomorphic" because they contain both epithelial and connective tissue components. Grossly they are round, smooth masses with thin, incomplete capsules. They grow slowly, but may become larger than other salivary tumors. Because the the thin capsule may have projections into the surrounding parotid tissue, it can be challenging to obtain the clean surgical margins that are needed to minimize recurrence. Treatment of benign mixed tumors involves the complete surgical removal of the affected gland. If the parotid gland is involved, "superficial parotidectomy" with removal of the gland's superficial lobe and facial nerve preservation is the procedure of choice. Warthin Tumor (" papillary cystadenoma lymphomatosum") Described by Warthin in 1929, this tumor is a smooth, soft, parotid or submandibular mass. It is well encapsulated when located in the parotid gland and contains multiple cysts. Malignant change has not been observed. All patients with this tumor survive, and the recurrence rate is 5%. The Warthin tumor can be bilateral (10% of cases) and is generally found in the major glands. Intraductal Papilloma This is a small, tan, smooth lesion that is generally found in the submucosal layer. Microscopically, the tumor contains cystically dilated ducts partially lined with a cuboidal epithelium. Oxyphil Adenoma ("oncocytoma") Oncocytomas of the salivary glands are very uncommon.They occur twice as often in women than in men, with patients being older than 50 years. The superficial lobe of the parotid gland is the most commonly reported location. Oncocytomas manifest as small (<5 cm in diameter), firm, slow-growing, spherical masses. A variety of other tumors can occasionally be seen in the salivary glands. These include:
Some controversy exists regarding the routine use of imaging for small lesions of the superficial lobe of the parotid gland, however, CT or MRI can be useful for suspected tumors of the deep lobe of the parotid gland and of the submandibular, sublingual, and minor salivary glands. These studies are useful for evaluating the local and regional extension of such tumors. The usefulness of Fine Needle Aspiration Biopsy is well established with many reporting accuracy rates of 74-90%. The procedure is generally safe, is simple to perform, and has low morbidity. Although some controversy exists about whether the procedure should be used for masses in the superficial lobe of the parotid, (since it may not change the management), results that are consistent with lymphoma or sialadenitis could make a large resection unnecessary and alleviate patient anxiety. Treatment Management of benign salivary tumors involves complete removal with an adequate margin of tissue to forestall recurrence. This usually requires the complete surgical removal of the gland containing the tumor.
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