Acute suppurative thyroiditis in appearance of unusual neck mass.

We report on three adult cases of acute suppurative thyroiditis due to infection through a piriform sinus fistula. In these cases, the lesion did not exhibit the clinical symptoms characteristic of acute suppuration, but appeared as an unusual neck mass. Repeated barium meal roentgenograms, however, demonstrated the internal fistula in two of the three cases. Acute suppurative thyroiditis may not be so rare even in adults. When acute suppurative thyroiditis occurs in adults with scanty symptoms of acute suppuration, the piriform sinus fistula could easily go undetected. Recognition of acute suppurative thyroiditis in adults per se seems to be important for correct diagnosis.