Data in the literature communicated in 63 publications were evaluated in which scintigraphically warm or hot nodules were described as identical to a follicular or papillary carcinoma diagnosed based on histology of the resection specimen, thus suggesting autonomous hyperfunction of a malignant thyroid neoplasia. In the majority of cases, this assumption could not be accepted, or only within strict limits. In these patients, it appeared more likely that the carcinoma was located adjacent to or within a benign hyperfunctioning thyroid area or that large masses of a thyroid carcinoma had only simulated the picture of a hyperfunctioning nodule by suppression of endogenous TSH and thus of the residual parenchyma's function. In other cases, the diagnosis of a hyperfunctioning thyroid carcinoma had to be doubted or rejected owing to the lack of plausibility of the documented morphological findings. At the end of the literature survey, only 10 case descriptions unequivocally verified that, though very rarely, a papillary or follicular thyroid carcinoma may manifest itself as a solitary warm or hot thyroid nodule. Such a scintigraphical finding thus cannot be regarded as proof of benignancy of a given thyroid tumour.