MULTIFOCAL PAPILLARY THYROID MICROCARCINO MA REVEALED BY A TOXIC NODULE

Discovery of a thyroid toxic nodule rarely leads to a diagnosis of thy roid carcinoma, although several cases have been reported in the liter ature. A 23-year-old man whose mother had a history of surgery for thy roid carcinoma presented with a 30-mm nodule in the left thyroid lobe. Serum free thyroxine was slightly elevated (26.3 pmol/L) and serum TS H was under 0.05 mIU/L. A scintiscan demonstrated a hot spot on the le ft with no uptake in the right lobe, which was, however, clearly visib le on the ultrasound scan. Histologic examination found a focus of pap illary carcinoma within the hot nodule and another focus in the right lobe. The most striking features of this case, namely the family histo ry, papillary histology, multifocal distribution, and small size of ea ch focus (less than 1 cm) are discussed based on data from the literat ure. Presence of a toxic nodule does not rule out thyroid cancer, alth ough this association is probably fortuitous in most cases.