Nine patients with painless or minimally painful subacute thyroiditis were
seen between late June and October 2000. Six had a history of antecedant vi
ral symptoms. Thyroid peroxidase antibodies were negative in eight patients
tested; none had a family history of autoimmune thyroid disease. It is pos
sible that these patients represent examples of postviral painless subacute
thyroiditis (atypical subacute thyroiditis). In order to establish the nat
ure of the syndrome, cytological examination, HLA typing, and long-term fol
low-up are necessary.