What causes parotid gland enlargement in sarcoidosis?

Parotid Gland Enlargement in Sarcoidosis

Parotid gland enlargement in sarcoidosis is caused by the formation of noncaseating granulomas within the glandular tissue, representing the same pathological process that occurs in other organs affected by this multisystem inflammatory disorder. Symmetrical parotid enlargement is a probable clinical feature supporting a diagnosis of sarcoidosis, resulting from granulomatous inflammation within the gland tissue. 1

Pathophysiology of Parotid Involvement

The parotid gland involvement in sarcoidosis follows the fundamental pathological process of the disease:

• Formation of noncaseating granulomas within the glandular tissue
• Accumulation of T-lymphocytes and macrophages forming epithelioid cell granulomas
• Potential presence of crystalline structures inside giant cells that can be detected on cytological examination 2
• Bilateral involvement in approximately 73% of cases with parotid sarcoidosis 3

Epidemiology and Clinical Significance

• Parotid gland involvement occurs in approximately 6% of all sarcoidosis patients 3, 4
• More common in women than men 3
• Typically presents in the 20-40 year age group 3
• May be the first or only manifestation of systemic sarcoidosis in rare cases 4, 5

Clinical Presentation

Parotid sarcoidosis typically presents as:

• Bilateral glandular enlargement (in 73% of cases) 3
• Often associated with xerostomia (dry mouth) 5
• May be accompanied by other sicca symptoms including xerophthalmia (dry eyes) 2, 5
• Can be part of Heerfordt's syndrome (a pathognomonic pattern including parotid enlargement, facial nerve paralysis, anterior uveitis, and fever) 3
• Often occurs with widespread involvement of other systems, particularly:
  • Intrathoracic manifestations
  • Peripheral lymphadenopathy
  • Uveitis
  • Lacrimal gland enlargement
  • Skin disease 3

Diagnostic Approach

Diagnosis of parotid sarcoidosis relies on:

1. Fine-needle aspiration cytology (FNAC) showing:

   • Epithelioid cell granulomas
   • Multinucleate giant cells
   • Possible crystalline structures inside giant cells
   • Negative staining for acid-fast bacilli 2

2. Imaging findings:

   • Parotid uptake on gallium scans and PET scans is considered a highly probable imaging feature supporting sarcoidosis diagnosis 1

3. Exclusion of other granulomatous diseases, particularly tuberculosis 2, 6

Clinical Implications

Parotid involvement has important clinical implications:

• May cause significant discomfort and cosmetic concerns
• Can lead to xerostomia and associated oral health problems
• Serves as a marker for potential multisystem involvement requiring comprehensive evaluation
• Offers an accessible site for diagnostic biopsy when sarcoidosis is suspected

Treatment Considerations

Management follows general sarcoidosis treatment principles:

• Systemic corticosteroids are the mainstay of treatment for symptomatic cases 6
• Immunosuppressive drugs may be required for refractory cases
• Topical corticosteroids may benefit some patients with primarily local symptoms 6
• Regular follow-up is essential, as recurrence can occur even years after initial presentation 4

Parotid gland enlargement should prompt consideration of sarcoidosis in the differential diagnosis, particularly when bilateral and associated with other symptoms like xerostomia and xerophthalmia, as early diagnosis and management can improve outcomes and quality of life.