Acute thyroiditis in a child: misleading result of fine-needle aspiration biopsy.

We report a case of acute thyroiditis in a 6-year-old girl, whose initial borderline clinical and sonographic data, coupled with the absence of leucocytes and bacteria on the fine-needle aspiration biopsy, led to the reversal of the initial diagnostic impression of acute thyroiditis and the institution of an inappropriate glucocorticoid treatment. Since both diseases are rare in the paediatric age group and therapy is completely different, we conclude that in borderline cases careful clinical observation and the response to the initial antibiotic therapy should be considered more reliable than any single morphologic or microbiologic result. We also suggest that acute bacterial thyroiditis could be usefully classified into two forms, suppurative and non-suppurative.