Congenital Parotid Fistula: Surgical Management in Two Infants and Review of Literature.

Congenital salivary gland fistulas are uncommon. They develop as a result of abnormalities of the first and second branchial arches. Operative and nonoperative methods of management have been described. We report two rare cases of congenital parotid fistula presenting to us in infancy that were managed surgically. Copyright:

INTRODUCTION

Salivary gland fistulas are rare entities which can originate from any of the salivary glands, but are mostly parotid in origin.[123] They may infrequently arise from ectopic or accessory glands as well as from normal parotid glands through an aberrant Stensen's duct. They may be congenital or acquired.[12] Salivary fistulas in children tend to be congenital compared to adults where it usually occurs secondary to facial and neck trauma, surgical procedures, and inflammation.[4] There are very few case reports in the indexed English literature on congenital parotid fistulas. Most patients managed surgically were more than 5 years of age, the youngest being 2-year-old.[5] Both our cases were infants who were managed surgically.

CASE REPORT 1

A 1-year-old girl presented with serous discharge from the right cheek since birth which increased on chewing. On examination, there was a 1 mm × 1 mm cutaneous opening over the right cheek, 2 cm lateral to the angle of the mouth along with bilateral preauricular skin tags [Figure 1a]. Intraoral examination and duct opening of parotid and submandibular gland was normal on both sides. Sinogram with a 24G cannula showed a thin tubular tract directed posteromedially from the external opening on the cheek into the region of the Stensen's duct/parotid gland [Figure 1b]. There was no communication with the oral cavity or mandible. Under general anesthesia, the external opening was cannulated with a 24G intravenous plastic cannula and methylene blue injected [Figure 1c]. With circumferential fine dissection around the external opening, the fistula tract was separated from the skin and subcutaneous fat of the cheek and brought into the oral cavity. Further intraoral dissection showed the tract initially going vertically down for 2 cm then turning posteriomedially for 1 cm to finally opening into the right Stensen's duct near the lower part of the parotid gland [Figure 1d]. The fistulous tract was transfixed and ligated at its origin in the duct and excised in toto [Figure 1e]. At 1-year follow-up, she has a negligible scar with a good cosmetic outcome [Figure 1f].

Figure 1

Pictures of case no. 1: (a) Salivary fistula 2 cm from angle of mouth. (b) Sialogram showing the fistula tract (arrow). (c) Injection of methylene blue into fistula via 24G cannula (arrow head) and intra oral dissection. (d) Identification of accessory duct by presence of dye. (e) Excised tract. (f) Cosmetic outcome at 1-year follow-up

CASE REPORT 2

An 8-month-old male child presented with salivary discharge from the right cheek since birth. On inspection, there was a 1 mm external fistulous opening, 2 cm from the angle of the mouth with ipsilateral preauricular appendage. Intraoral examination was normal. On sinogram, no obvious tract could be identified. Under general anesthesia, cannulation of external fistulous opening was extremely difficult due to its very narrow caliber. A 24G plastic cannula could be passed for only 5 mm through which methylene blue dye was injected. Similar dissection was done as in the previous case with the tract being dissected externally and transposed intraorally. Diffuse intraoral discoloration by the dye was noted and insufficient length of cannula within the duct made identification of further intraoral tract difficult and the procedure had to be abandoned. The preauricular skin tag was excised. Postoperatively, there was local edema and a small dry ulcer over the cheek [Figure 2]. It eventually healed with secondary intention. At 1-year follow-up, there is no external salivary discharge with good cosmetic outcome.

Figure 2

Postoperative pictures of case no. 2 taken 1 month after surgery showing a small ulcer at the site of the original salivary fistula

DISCUSSION

A salivary gland fistula is an anomalous connection between any of the salivary glands or their ducts and the cutaneous surface, through which saliva is discharged.[4] Congenital parotid gland fistula usually open on the facial skin near the angle of the mouth.[1] They can also open in the retroauricular region, mucosa of oral cavity, and neck.

Embryologically, once the maxillary and mandibular processes that originate from first branchial arch get fused, the normal position of parotid duct at the level of superior second molar is attained inside the mouth.[3] Some primitive tissue of parotid gland accompanied by its duct may get isolated from its parent tissue with an arrest in migration posteriorly and get placed anterior to the main parotid gland.[5] This explains why congenital parotid fistulas open near the oral commissure, in the line of fusion of maxillary and mandibular processes as seen in both our cases.[35] Although both our patients had right sided fistula with one each in a boy and a girl, literature review suggests no strong predeliction for laterality with the left side being involved only 1.29 times more often than the right.[5] Male dominance has been noted in a ratio of 1.67:1.[5]

If the fistula is accompanied by ipsilateral preauricular appendage and rarely mandibular hypoplasia, it can be considered as a component of oculo-auriculo-vertebral spectrum, due to developmental anomalies of the first two pharyngeal arches.[5] Two such cases have been reported with Goldenhar syndrome, a hereditary disorder characterized by several other anomalies affecting the first and second branchial arches.[6] Both our patients had congenital salivary fistula and preauricular appendages, with no other obvious abnormalities.

Accessory parotid glands occur as a common variant in nearly 21% of the population and are generally continuous with the Stensen's duct. The ectopic accessory parotid system (EAPS) is a term described recently for a parotid gland fistula arising from an ectopic accessory gland and accessory parotid gland possessing its own duct and is very rare.[357]

Conventional sinogram was done in both our cases. It delineated the tract in the first case, but was not useful in the second. Computed tomography or magnetic resonance (MR) fistulography may delineate the anatomy better with the latter giving superior soft-tissue resolution including detection of EAPS. Combining conventional sinogram with MR fistulography may be the investigation of choice.[5] However, age of the child and narrow caliber of the duct may not make these studies feasible.[8]

Although numerous conservative and operative modalities have been described, success rates are variable. Conservative methods are directed toward reducing the parotid secretions. The surgical procedures include those that divert the secretions into the mouth and those that decrease secretions of parotid either by ligation or excision of duct and rarely, superficial parotidectomy. Fibrin glue has been used for acquired post parotidectomy fistulas in adults. Recurrence is high due to inactivation of the glue by saliva.[9] Hot hypertonic saline has also been tried in different concentrations in postsurgical fistulas in adults but not reported in congenital fistulas.[10] Chemocauterization with 35%–50% trichloroacetic acid has been tried in a 5-year-old girl with good cosmetic outcome, but requires general anesthesia with multiple applications.[11]

Among the surgical methods, duct ligation can lead to postoperative pain, edema, and gland engorgement. Patients with EAPS are better managed by complete excision of the tract along with the ectopic gland. Superficial parotidectomy has also been performed, but it is a very radical procedure for this condition with chances of facial nerve injury.[4] Delore's method of intraoral transposition of the duct for salivary drainage has been successfully done by many surgeons.[1] While we were able to completely excise the accessory duct in the first case, in the second case, the exact course of the fistula could not be delineated. The external opening was transposed intra orally with good results. In infants with a narrow delicate tract, this procedure may be sufficient rather than injuring the main parotid duct. Both our cases will be kept on long-term follow-up to look for any recurrence or parotitis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.