Non-tumor-associated psammoma bodies in the thyroid

Psammoma bodies in the thyroid are common in glands with papillary thyroid carcinoma. Psammoma bodies that are not associated with tumor cells, however, represent a diagnostic problem for pathologists. Should we treat isolated psammoma bodies as representing metastatic disease? This study included patients who had non-tumor-associated psammoma bodies in their thyroids or in the perithyroidal lymph nodes. Clinical, pathologic, and follow-up information was obtained for the patients. Our results indicate that 27 of 29 patients had a contralateral or an ipsilateral tumor, the majority of which were papillary. We noted a high frequency of microscopic carcinomas (12/27) and of tall cell variants of papillary thyroid carcinoma (8/27 cases). Based on these findings, we recommend that thyroid glands with non-tumor-associated psammoma bodies and no histologically identified carcinoma be entirely submitted to identify any microscopic carcinoma. If no carcinoma is identified in a lobectomy, discussion with the surgeon should indicate the need for close clinical follow-up.