RECURRENT PAROTID SWELLING
Posted by headnecksurgery on February 20, 2009
The differential diagnosis for recurrent parotid gland swelling includes autoimmune “pseudosialectasis” and Mikulicz syndrome. If the former is localized to the parotid gland, it is called Mikulicz disease; there are adult and pediatric forms. If autoimmune parotitis is associated with xerophthalmia or xerostomia, it is called sicca syndrome or primary Sjögren disease. If primary Sjögren disease is associated with a connective tissue disorder, it is called secondary Sjögren disease. Mikulicz syndrome is essentially a term used for all cases of recurrent parotid swelling that are not autoimmune conditions. It includes three major categories: chronic recurrent sialadenitis, sialosis, and multinodular gland.
At present, the exact cause of Sjögren syndrome continues to be unknown. The Epstein-Barr virus, cytomegalovirus, human herpesvirus 6, and retroviruses have been implicated by different studies, but convincing proof has not been provided that one of these viruses is the etiologic agent.
Autoimmune Parotid Swelling
The autoimmune diseases of the parotid gland have a unifying histologic pattern of an early lymphocytic infiltrate, followed by thinning and fragmentation of the connective tissue in the terminal or intercalated duct walls with destruction of the acini. The larger ducts are usually uninvolved unless there is a superimposed infection. The sialographic appearance is also similar. It consists of a diffuse pattern of globular collections of contrast material, originally called sialectasis. It was thought that there was dilatation of the acini and collection of the contrast material within them. It is now known that the weakened acini allow extravasation of contrast material, which form extramural globular collections. There are four progressive radiographic features of autoimmune parotid swelling: punctate, with spherical collections of 1 mm or less; globular, with the collections of 1 to 2 mm: cavitary, with large irregular collections of uneven distribution; and destructive, with no recognizable branching. The latter two stages represent superimposed infection.
Autoimmune parotitis usually presents as unilateral recurrent swelling that is painless, of unpredictable duration, and rarely associated with edema. Most childhood forms resolve at puberty and do not progress to the latter two radiographic stages. The adult form is 10 times more common. Sjögren syndrome is the second most common connective tissue disorder, superseded only by rheumatoid arthritis. It may occur at almost any age, typically between ages 40 and 60, and is more common in women, with a 9:1 female predominance.
The symptoms include xerostomia, xerophthalmia, and parotid swelling. Filamentary keratitis, diagnostic of keratoconjunctivitis sicca, is a common finding. The most common connective tissue disorder associated with secondary Sjögren syndrome is rheumatoid arthritis. Other extraglandular symptoms include dry skin, vaginal pruritus, arthralgia, and myalgia.
Patients suspected of having Sjögren syndrome may require laboratory studies to better define the disease process. Certain humoral antibodies are characteristic of the disease. SS-A and SS-B are autoantibodies found exclusively in primary Sjögren syndrome. Determination of antibodies to specific human leukocyte antigen (HLA) antigens also can help differentiate the primary and secondary forms. The primary form has a high correlation with HLA-B8 and HLA-DW3 antibodies. The secondary form is associated with HLA-DW4 antibody. Rheumatoid factor and antinuclear antibodies may be present in both disease forms. The erythrocyte sedimentation rate is often elevated in both forms. Quantitative analysis of immunoglobulins often shows polyclonal hypergammaglobulinemia.
About 5% of patients with Sjögren syndrome develop a lymphoproliferative neoplasm. The greatest risk for degeneration is seen in patients with the primary form, constant parotid swelling, and lymphadenopathy. A decrease in serum IgM levels heralds the progression to malignancy.
A prominent diagnostic tool is the lip biopsy, with the specimen usually obtained just lateral to the midline on the mucosal surface of the lower lip. From the biopsy, a focus score is obtained. A focus is 50 or more lymphocytes, histiocytes, or plasma cells. The score is determined by counting the number of foci in 4 mm2. A score greater than 1 is characteristic of Sjögren syndrome. Siccalike syndrome is similar to Sjögren syndrome but has a negative biopsy. Treatment of Sjögren syndrome is usually supportive. Oral steroids or steroid eye drops are usually reserved for severe disability.
Mikulicz syndrome represents several clinical entities in three major groups: recurrent sialadenitis, sialosis, and multinodular gland. Recurrent sialadenitis presents as a unilateral, swollen, red, tender gland with purulent discharge, often with pain on chewing. Sialography reveals dilation and focal narrowing of Stensen duct. The peripheral ducts are usually normal. Sialectasis is usually focal and nonuniform. Because of the distinct clinical picture, sialography is rarely performed on these patients. The indications for sialography are to demonstrate a stone or stricture, to differentiate from autoimmune disease, and to evaluate the extent of irreversible ductal disease. Treatment of recurrent sialadenitis begins with demonstration and removal of any stones. The patient is further treated with antibiotics, warm compresses, and sialogogues. In severe cases, excision may be necessary.
Sialosis is a recurrent bilateral nontender parotid swelling that occurs almost exclusively secondary to underlying pathology, including cirrhosis; diabetes; alcoholism; malnutrition; or ovarian, thyroid, or pancreatic insufficiency. Sialosis also can result from using sulfisoxazole, phenylbutazone, catecholamines, or iodide-containing compounds. Sialography reveals an enlarged gland with normal peripheral ducts that are merely more spread apart. Treatment consists of removing the underlying cause.
“Multinodular gland” represents a group of diseases with lumpy parotid glands. Although rare, autoimmune sialadenitis can present in this fashion. The remainder of causes include granulomatous diseases, lymphoproliferative neoplasms, and other tumors. Granulomatous diseases involving the parotid include tuberculosis and sarcoid. About 10% to 30% of patients with sarcoid have involved parotids. In Heerfordt syndrome, sarcoid involves the facial nerve, producing facial swelling, uveitis, and facial paralysis. Lymphoma often presents like this in the parotid. A computed tomogram-sialogram is helpful in differentiating this from other causes of parotid swelling. Warthin tumor is the most common tumor of parotid origin that presents as a multinodular gland.
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