What psammoma bodies can represent in the thyroid. What we recently learnt from a story of lack of evidence.

The detection of psammoma bodies (PBs) in the thyroid gland is commonly associated to classic papillary thyroid carcinoma (PTC) and are frequently encountered in differnt subtypes of PTCs. Nonetheless, the evidence of PBs without a PTC may represent a diagnostic challenge. The general statement is that PBs represent a metastatic finding of PTC either when encountered inside the thyroid parenchyma or in the perithyroidal lymph nodes. The majority of authors assess that in presence of PBs, a search for an occult PTC is strongly encouraged and mandatory, especially if a lobectomy had been performed. In fact, it is not uncommon that a contralateral or ipsilateral tumor, mostly PTC, is found leading to the suggestion that the best recommendation is to submit the entire thyroid tissue. Nonetheless, when a cancer has not been found, the possibility of the rare evenience that PBs are likely to be associated with benign conditions should be considered among the differential diagnosis. Herein a short commentary and review of the literature on PBs detection and its diagnosis, based on our recent experience.