Recurrent acute suppurative thyroiditis attributable to a piriform sinus fistula in an adult

To report a case of recurrent acute suppurative thyroiditis (AST) caused by a piriform sinus fistula (PSF).

We review the related literature and describe the clinical presentation, diagnostic evaluation, and management of a patient with recurrent AST due to PSF.

A 50-year-old woman presented with recurrent episodes of pain and swelling in the left anterior neck area and odynophagia. The initial episode, 1 year previously, lasted for 1 month, and her condition improved with a short course of prednisone. Subsequently, the neck pain recurred and extended upward to both sides of the neck. She was suspected of having thyroiditis and was treated with prednisone for 6 weeks, but the symptoms persisted. Physical examination showed tenderness and induration of the skin over the left lobe of the thyroid. Ultrasonography disclosed an ill-defined solid-cystic area in the left thyroid lobe. Fine-needle aspiration cytology revealed acute inflammation, consistent with an infected cyst. A computed tomographic scan of the neck showed obscuration of the fat planes involving the left strap musculature and evidence suggestive of microabscesses. Prolonged intravenous antibiotic treatment ultimately alleviated the symptoms. Direct laryngoscopy revealed a fistula extending anteriorly from the apex of the piriform sinus. The patient underwent complete fistulectomy and left thyroid lobectomy and was asymptomatic on followup.

PSF should be suspected as a cause of recurrent AST. Absence of fever, toxemia, and local erythema does not rule out the condition. Unresponsiveness to corticosteroid therapy in thyroiditis should suggest the diagnosis. Complete fistulectomy and resection of the involved thyroid lobe result in permanent cure.