Congenital piriform fossa sinus tract presenting as an asymptomatic neck mass in an infant

Branchial fistula arising from pyriform fossa: CT diagnosis of a case and discussion of radiological features

Anomalies of third or fourth branchial apparatus origin are very uncommon and present as recurrent neck infections or thyroiditis with a predominant left-sided involvement. Radiological diagnosis requires a high index of suspicion and is critical for initiation of proper treatment. We describe a case of branchial sinus of pyriform fossa with external fistulization that presented in adulthood and was diagnosed on computed tomographic scan. The radiological features of this rare anomaly are revisited.

[Diagnostic imaging of piriform sinus fistulas]

OBJECTIVES

To establish the usefulness of ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and barium contrast swallow studies in the diagnosis of piriform sinus fistulas (PSF).

MATERIAL AND METHODS

We reviewed the clinical histories and imaging studies of four pediatric patients diagnosed with PSF. Cervical ultrasound was the first imaging study performed in all cases. Three patients subsequently underwent intravenous contrast-enhanced CT examination and one underwent MRI. Barium contrast swallow studies were performed in all patients at a later time. All cases were confirmed at surgery.

RESULTS

Ultrasound enabled the lesions to be located on the left side and showed the existence of heterogeneous collections in and around the thyroid glands in all four patients. Posterior CT and MRI studies determined the exact size of the abscessed lesions. Barium contrast swallow studies demonstrated the existence of the PSF in all four cases.

CONCLUSIONS

The presence of a recurrent inflammatory process and acute suppurating thyroiditis located on the left side should raise suspicions of PSF. Both CT and MRI are useful in the study of PSF; however, in our experience, ultrasound examination is the technique of choice for initial evaluation and follow-up. After the acute process, barium swallow studies continue to be the main method for diagnosing the trajectory of the fistulous tract.