Atypical subacute thyroiditis: preliminary observations.

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