Histological changes mimicking papillary carcinoma following fine needle aspiration of the thyroid gland.

A puzzling artifact caused by previous fine needle aspiration of the thyroid in a 26 year-old woman is reported. The lesion, which mimicked a papillary microcarcinoma, was seen into a follicular adenoma with focal oncocytic changes. The literature concerning histological changes following aspiration cytology in the thyroid and other organs is reviewed. These morphologic changes (notably in the thyroid gland), can be varied and should always be kept in mind in order to avoid misdiagnoses.