抄録
Unlike subacute and chronic thyroiditis, acute suppurative thyroiditis with subsequent abscess formation is rarely encountered in clinical practice. The route of infection in recurrent acute suppurative thyroiditis was obscure until Tucker et al first suggested the presence of a congenital fistulous tract extending from the piriform sinus to the side of the neck. The relation between acute suppurative thyroiditis and an internal fistulous tract (piriform sinus fistula) as the route of infection was confirmed by Miyauchi et al. Since then, a number of similar cases have been reported and, at present, piriform sinus fistulae are considered to be the most common route of infection inducing recurrent acute suppurative thyroiditis.
Piriform sinus fistula is a persistent congenital sinus tract, which arises from the apex of the piriform sinus and ends in or adjacent to the thyroid lobe, and is characterized by the exclusively leftsided occurrence. The fistulae are assumed to arise from remnants of the 3rd or 4th pharyngeal pouch, or the ultimobranchial body, but its exact origin remains controversial.
In this paper, we describe two patients with recurrent acute suppurative thyroiditis and abscess caused by infection through the piriform sinus fistula. Repeated barium meal studies demonstrated a thin fistula in one of the two patients. After fistulectomy, recurrent disease developed in one of the two, indicating incomplete removal of the fistula. This patient underwent revision surgery later. Barium contrast studies and endoscopic examination were useful in making the diagnosis accurately, and surgical exploration of the neck with excision of the entire fistulous tract to the level of the piriform sinus is the treatment of choice.
