[Preclinical hyperthyroidism in thyroid invasion by tumors of other organs]

Inclusion of that degree of supranormal autonomous thyroid function which induces TRH-refractoriness without clinical hyperthyroidism (i.e. preclinical hyperthyroidism), and a high prevalence of autonomously functioning multinodular goiter results in a high incidence of hyperthyroidism in thyroid malignancy. In a series of 56 consecutive patients with differentiated thyroid carcinoma 17 (30%) had a coincidental multinodular goiter with preclinical (21%) or overt (9%) hyperthyroidism. Furthermore, preclinical hyperthyroidism was found in 2 out of 5 patients with secondary carcinoma and malignant lymphoma of the thyroid respectively. These patients' cases are presented in detail; they had no concomitant nodular goiter or signs of immunogenic autonomous thyroid function. The observation confirms the facultative occurrence of supranormal thyroid hormone release induced by tumor invasion and morphologic destruction of follicles.