Giant Parotid Sialolithiasis: Report of a case with review of literature

Sialoliths are calcified structures that develop within the salivary ductal system (1). Sialolithiasis is the most common disease of salivary glands (2). Sialolithiasis accounts for 30% of salivary diseases (1). It is estimated that it affects 12 in 1000 adult population. Males are twice as much affected as females (2), especially in cases of parotid gland lithiasis (1). Sialolithiasis usually occurs between the ages of 30-60 years, though cases of teenagers have also been reported (3). Children are rarely affected (1). Sialolithiasis mainly occurs with reference to sub-mandibular gland (80%-90%), to a lesser degree in parotid gland (5%-20%) and the sublingual and minor salivary glands (1% to 2%). Bilateral or multiple-gland sialolithiasis is occurring in fewer than 3% of cases (3) . In patients with multiple stones, calculi may be located in different positions along the salivary duct and gland. Sialolithiasis occurs equally on the right and left sides. 40% of parotid and 20% of submandibular stones are not radiopaque and sialography may be required to locate them (4) . The sialolith should be at-least 30% mineralized to be detected by radiographic study. Salivary calculi are usually unilateral and are not a cause of dry mouth (4) . Clinically they are round or ovoid, rough or smooth and of a yellowish color. They consist of mainly calcium phosphate with smaller amounts of carbonates in the form of hydroxyapatite, with smaller amounts of magnesium, potassium and ammonia. This mix is distributed evenly throughout (5) . Submandibular stones are 82% inorganic and 18% organic material whereas parotid stones are composed of 49% inorganic and 51% organic material (6).The organic material is composed of various carbohydrates and amino acids (6). Bacterial elements have not been identified at the core of a sialolith (6) . The difference in chemical properties of the saliva secreted by both the glands explain the difference between the organic and inorganic constituents of parotid and submandibular gland. Commonly, Sialoliths measure from 1 mm to less than 1 cm. Giant salivary gland stones (GSGS) are those stones measuring over 1.5 cm and have been rarely reported in the medical literature.(6,7) GSGS measuring over 3 cm are extremely rare, with only scant reported cases.(8) This case presents the clinical and radiographic features of a rare giant sialolith of Parotid duct measuring 1.5 cm ×1.3 cm in size with a reflection of review of literature, demographic variables and possible aetiopathogenesis.