Giant calculus of the submandibular salivary duct.

Sialolithiasis is the most common pathology of the submandibular gland, as 80% of all salivary duct calculi form in the submandibular (Wharton's) duct. (1) A lower incidence of calculi is found in the parotid duct and in the sublingual duct--up to 20 and 2%, respectively. (2) Sialoliths are more common in men than in women, and most occur in patients aged 50 to 80 years. (3) The predisposition of the submandibular gland and duct to calculi formation can probably be attributed to the alkaline and viscous composition of the saliva and the high concentration of calcium, mucin, and phosphate ions in submandibular secretions. The longer course and angulation of Wharton's duct also is associated with slower salivary flow rates. (4) Most patients with sialolithiasis present with a solitary stone, and most submandibular stones develop within the duct itself. (2,5)

We evaluated a 27-year-old man who complained of a painful mass in the left floor of the mouth. On bimanual examination, a firm fusiform mass was palpated along the course of Wharton's duct on the left; the mass was tender to palpation. Computed tomography (CT) of the neck demonstrated a large radiopaque mass in the left submandibular triangle that extended anteriorly to the submental area (figure 1).

[FIGURE 1 OMITTED]

The patient was taken to the operating room for a transoral sialodochoplasty and removal of the large submandibular calculus. Marsupialization of Wharton's duct was performed at the end of the operation to prevent postoperative stricture and obstruction. The submandibular calculus was removed in two pieces; the anterior one-fourth of the calculus had fractured away from the rest of the stone, a feature that was evident on CT. The entire sialolith measured 35 mm in length, it had a relatively smooth surface, and it was fusiform is shape (figure 2).

[FIGURE 2 OMITTED]

Giant salivary gland calculi are exceedingly rare; in 2002, Bodner reported that only 14 well-documented cases had been published in the literature since 1942. (6) The largest sialolith reported to date measured 55 mm in length. (7) Approximately 80% of submandibular stones are radiopaque on standard x-ray films. (3) The classic occlusal film can reliably show ductal sialoliths, but small and intraglandular stones may be missed. CT can pick up large stones, and it can detect smaller stones if 1-mm fine cuts are obtained. Accurate localization of the stones and precise ductal anatomy, however, is lacking with CT. (8) Ultrasonography is a popular noninvasive modality used in Europe to diagnose sialolithiasis, but it is operator-dependent and it does not provide the surgeon with a direct anatomic image for localization. (9) Sialography has conventionally been the gold standard because it not only diagnoses sialolithiasis, it also provides an image of the ductal system. However, sialography subjects the patient to radiation and carries a risk of ductal perforation and retrograde displacement of the stone with injection. (10) Magnetic resonance sialography is a newer diagnostic modality that allows for visualization of the ducts without any radiation or dye injection, but it is limited by its cost and feasibility in claustrophobic patients. (11)

Choosing an approach to surgical treatment of submandibular sialolithiasis largely depends on the stone's location. For stones that are located entirely in the duct and close to the papillae, a transoral sialodochoplasty is sufficient. For intraglandular stones and for stones that are embedded in the hilum of the gland, a submandibular gland excision via an extraoral approach is indicated. Among newer treatments are external lithotripsy and different techniques in interventional sialendoscopy, including wire-basket extraction and fiberoptic laser lithotripsy with basket retrieval. (12)

References

(1.) Gayner SM, Kane W J, McCaffrey TV. Infections of the salivary glands. In: Cummings CW, ed. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby: 1998:1239-40.

(2.) McKenna JE Bostock DJ, McMenamin PG. Sialolithiasis. Am Fam Physician 1987;36:119-25.

(3.) Thoma KH, Gorlin RJ, Goldman HM, eds. Thoma's Oral Pathology. St. Louis: Mosby: 1970.

(4.) Mason DK, Chisholm DM. Salivary glands in health and disease. Philadelphia: W.B. Saunders: 1975.

(5.) Lustmann J, Regev E, Melamed Y. Sialolitbiasis. A survey on 245 patients and a review of the literature. Int J Oral Maxillofac Surg 1990;19: 135-8.

(6.) Bodner L. Giant salivary gland calculi: Diagnostic imaging and surgical management. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002:94:320-3.

(7.) Paul D, Chauhan SR. Salivary megalith with a sialo-cutaneous and a sialo-oral fisutla: A case report. J Laryugol Otol 1995; 109:767-9.

(8.) Avrahami E, Englender M, Chen E, et al. CT of submandibular gland sialolithiasis. Neuroradiology 1996;38:287-90.

(9.) Rinast E. Gmelin E, Hollands-Thorn B. Digital subtraction sialography, conventional sialography, high-resolution ultrasonography and computed tomography in the diagnosis of salivary gland diseases. Eur J Radiol 1989:9:224-30.

(10.) Cockrell DJ, Rout PG. An adverse reaction following sialography. Dentomaxillofac Radiol 1993:22:41-2.

(11.) Becker M, Marchal F. Becker CD, et al. Sialolithiasis and salivary ductal stenosis: Diagnostic accuracy of MR sialography with a three-dimensional extended-phase conjugate-symmetry rapid spin-echo sequence. Radiology 2000;217:347-58.

(12.) Marchal F, Dulguerov P. Sialolithiasis management: The state of the art. Arch Otolaryngol Head Neck Surg 2003;129:951-6.

Edwin K. Chan, MD; Nilesh D. Patel, MD

From the Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary, New York City.