Thyroid carcinoma presenting as a pertechnetate "hot" nodule, but without 131I uptake: case report.

A 24-year-old woman presented with a mass on the right side of the neck; this proved to be a hyperfunctioning or "hot" nodule on pertechnetate scan. Because of the firmness of the area, the study was repeated with 131I, but the region did not accumulate radioiodide. The tissue showing this discrepant handling of pertechnetate and radioiodide was surgically removed and identified as a follicular carcinoma with papillary foci. A brief review of the literature data on the disassociation of thyroid trapping and organification functions, and hence of possible discrepancies between pertechnetate and radioiodide uptake, is given.