Submandibular Duct Fistula Caused by a Large Sialolith: Incidental Finding in a Barium Swallow Study

This case report details an incidental finding of a submandibular duct fistula to a patient's posterior mouth floor found on a barium swallow examination that was performed to rule out gastrological causes of substernal chest pain. The radiologist was unable to determine the cause of the filling defect at the time of the study. The patient's history revealed that a large calculus of unknown size had been passed spontaneously through the floor of the mouth, rupturing the proximal gland duct and creating the fistula.

Sialolithiasis is the formation of calculi in the salivary gland and is the most common disease of the salivary glands, with the submandibular glands affected more often than others. The condition is more common in men than in women and most often affects individuals aged between 30 and 60 years.

In general, the etiology of sialolithiasis is unknown. However, examining comorbidities and possible risk factors, such as tobacco use, and how they alter the saliva and the function of the salivary glands might lead to a better understanding of their cause.