Abstract B60: Ultrasound microcalcification does not indicate psammoma bodies in thyroid nodules

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Abstract B60 Background The increasing incidence of thyroid nodules is associated with high resolution ultrasound (US) use. Thyroid nodules with irregular margins, vascular spots and microcalcifications in the US analysis have been described as malignant, and no fine needle aspiration (FNA) biopsy is suggested in some centers. It is thought that psammoma bodies, -a very specific finding of papillary thyroid carcinoma- within a nodule, produce the US microcalcifications.The aim of the present study is to identify if psammoma bodies are the source of the ultrasonographic microcalcifications. Methods Consecutive US performed in patients with thyroid nodules seen at the thyroid clinic between May 2007 and May 2008 were assessed to identify microcalcifications, margins and vasculature. Cases submitted to thyroidectomy were grossly sampled in suspected zones. Specimens were fixed in buffered formalin, embedded in paraffin and stained with haematoxylin and eosin for histological study. A systematic search for psammoma bodies, dystrophic/non dystrophic small and large calcifications was performed and a histological diagnosis was rendered. Correlation of US microcalcifications and the type of calcification in the different morphological categories was performed. Evaluators were blind and sampling was standardized according to nodule size. Results Fifty four patients were included (papillary carcinoma 35, goiter 16, adenoma, Hashimitos thyroiditis and anaplastic carcinoma 1 each). Morphologic analysis depicted psammoma bodies only in papillary carcinoma but also macro calcifications (29%), dystrophic micro calcifications (34%) and Monckeberg vascular calcifications (26%). Macro calcifications were evenly distributed between papillary carcinoma and goiter. No calcifications were identified in 30% of US interpreted as having microcalcifications. Conclusion Micro calcifications observed in US are not specific of psammoma bodies or malignancy. A careful interpretation of US micro calcifications is mandatory in thyroid nodule screenings. Citation Information: Cancer Prev Res 2008;1(7 Suppl):B60.