Chronic sclerosing sialadenitis is a chronic inflammatory condition affecting the salivary glands, causing them to harden and enlarge. It is frequently linked to IgG4-related disease, a broader systemic disorder.
Understanding Chronic Sclerosing Sialadenitis
The term “sclerosing” refers to fibrosis, the formation of excess fibrous connective tissue that causes the affected tissue to become firm or hardened. This process stems from chronic inflammation, where the immune response leads to collagen deposition. The affected salivary gland, most commonly the submandibular but sometimes the parotid, gradually transforms into a dense, firm mass.
This inflammatory process causes diffuse enlargement and a rubbery to firm consistency of the gland. Microscopically, the gland shows extensive lymphoplasmacytic infiltration (an accumulation of lymphocytes and plasma cells) and significant fibrosis. This fibrotic change replaces normal glandular tissue, impairing its function over time.
Recognizing the Signs
Individuals with chronic sclerosing sialadenitis present with a painless or mildly painful swelling of the affected salivary gland. This swelling develops gradually over weeks or months and is persistent. Upon palpation, the gland feels firm to hard, distinguishing it from acute inflammatory conditions that are often more tender.
The submandibular gland beneath the jaw is the most frequently involved site, causing a noticeable lump in the neck. Less commonly, the parotid glands in front of the ears can also be affected. If salivary gland function is significantly impaired by fibrosis, individuals might experience dry mouth (xerostomia). Patients often seek medical attention due to cosmetic concerns or a perceived mass.
Pinpointing the Cause and Diagnosis
Chronic sclerosing sialadenitis is recognized as a manifestation of IgG4-related disease (IgG4-RD), a systemic fibroinflammatory condition. IgG4-RD is an immune-mediated disorder characterized by elevated serum IgG4 levels and infiltration of IgG4-positive plasma cells into various tissues. Other causes like salivary duct obstruction or infection are typically ruled out.
Diagnosis begins with a clinical examination, where a physician assesses gland size and consistency through palpation. Imaging studies (ultrasound, CT, MRI) then evaluate the gland’s internal structure and size, helping differentiate it from tumors or cysts. These can show diffuse enlargement and a homogeneous appearance.
Blood tests check for elevated serum IgG4 levels, which support an IgG4-RD diagnosis. However, normal IgG4 levels do not rule it out, as some patients with confirmed IgG4-RD may have levels within the normal range. For a definitive diagnosis, a tissue biopsy (fine-needle aspiration or excisional) is often necessary. This biopsy reveals characteristic features: dense lymphoplasmacytic infiltration, distinctive “storiform” (wagon-wheel pattern) fibrosis, obliterative phlebitis (vein inflammation and obliteration), and a significantly increased number of IgG4-positive plasma cells.
Managing the Condition
Medical management is the primary approach for chronic sclerosing sialadenitis, given its inflammatory and immune-mediated nature, especially when associated with IgG4-related disease. Corticosteroids, such as prednisone, are typically the first-line treatment. These medications suppress the immune system and reduce inflammation, leading to decreased gland size and improved symptoms for many patients. The response to corticosteroids is often favorable, with noticeable reduction in swelling within weeks.
After an initial period of high-dose corticosteroids, the dosage is usually tapered gradually over several months to prevent recurrence and minimize side effects. Some patients may require long-term low-dose maintenance therapy. For individuals who do not respond adequately or experience frequent relapses, other immunosuppressive agents may be considered. Medications like rituximab, a monoclonal antibody targeting B cells, have shown promise in managing IgG4-RD and its manifestations by modulating the immune response.
Surgical intervention, such as excision of the affected salivary gland, is generally reserved for specific circumstances. These include uncertain diagnosis despite imaging and blood tests, failed medical therapy, or severe cosmetic deformity. Surgery is not the primary treatment due to the systemic nature of IgG4-RD and the potential for other organs to be affected. Following treatment, ongoing monitoring is important to assess disease activity, detect recurrence, and identify involvement of other organs if the condition is part of broader IgG4-related disease.