Introduction

Sialolithiasis is a common disease of the salivary glands and is caused by formation of sialoliths.¹  Sialoliths are calcified masses that develop in the intra- or extra-glandular duct system and form as a result of mineralization of debris that have accumulated in the duct lumen.  These debris may include mucous plugs, bacterial colonies, exfoliated duct epithelial cells, foreign bodies, or other cellular debris.²  Chemically, sialoliths are condensations of calcium salts, primarily calcium phosphate and calcium carbonate showing the apatite structure, with small amounts of other inorganic and organic components.³

Sialolithiasis may occur in any major salivary gland but is most common in the submandibular gland.¹  There are two reasons for this phenomenon.  The submandibular saliva is rich in mucus and is, thus, more viscous than parotid saliva.  In addition the submandibular duct ascends when the body is upright, it bends at the posterior edge of the mouth, and its course is long and sinous.⁵  Because of the horseshoe-shape of the body of the gland, this duct has a bow-shaped course in the cranial direction, which means there is a particular tendency in this gland to secretory congestion and concrement formation.

Histologically, sialoliths have a concentric, laminated structure of alternating layers of organic and inorganic substances.  The calculi are often built up around one or more central cores, while in some cases a central core is lacking.⁶

The precise cause of sialolith formation is still largely unexplained but infection or inflammation of the gland, the viscous nature of mucous secretions, and others have all been suggested as predisposing factors for their development.⁴

The disturbance in salivary secretion and the change in the composition of saliva, which was called dyschylia by Seifert, leads to an increase in salivary viscosity and to a slime obstruction in the terminal ducts of the gland.  The disturbance in salivary secretion and increased formation of microliths in ducts support the ascent of bacteria and cause focal obstructive atrophy of the gland parenchyma.⁴  Salivary dysfunction may be due to systemic diseases, medications, and head and neck radiotherapy.⁸  Loss of renal function results in the accumulation of metabolic waste products and alters the normal hemostatic mechanisms that control fluid and electrolyte balance.¹⁰  It is described that many uremic patients suffer from xerostomia⁹.

This paper presents a case of sialolith of the submandibular gland in a renal transplant patient.

Case Report

A 58-year old woman was referred to the São Lucas Hospital (PUCRS, Brazil) with the chief complaint of a painful swelling on the left submandibular gland, accompanied by difficulty in swallowing.  She had recurrent episodes of swelling and pain of the submandibular region over the past few years.  On anamnesis she revealed she has been on dialysis in the past, had a kidney transplanted the last year, and was under immunosuppressive therapy.  On physical examination, the patient had a purulent discharge from the left Wharton duct with a palpably enlarged submandibular gland.  Ultrasonography and a radiograph suggested the existence of an intraglandular sialolith (Figures 1 and 2).

Figure 1.  Panoramic radiograph shows a large radiopaque mass in the left mandibular area.

Figure 2.  Ultrasound view of the right submandibular gland in showing stone.

The diagnosis of sialolithiasis with supurative inflammatory was made.  After antibiotic and anti-inflammatory treatment, the patient was admitted into the hospital.  Under general anesthesia, a large calculi and the left submandibular gland were removed using a Risdon approach (Figures 3 and 4).

Figure 3.  Risdon approach for excision of submandibular gland.

Figure 4.  Gross specimen of the left sublingual gland and thesialoliths.

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Citation Number: Vol. 6, No. 3, Page 128