METASTATIC FOLLICULAR CARCINOMA OF THE THYROID - REAPPEARANCE OF RADIOIODINE UPTAKE

Dedifferentiation of well-differentiated thyroid carcinoma is a well-k nown phenomenon that may lead to the disappearance of radioiodine upta ke in tumors and the inability to treat patients with radioiodine. We report a patient in whom the I-131 uptake progressively diminished to such low levels after a cumulative dose of 31.5 GBq that further I-131 administration was considered nonbeneficial. Thereafter, metastases i n the lungs and skeleton progressed. Because of the absence of any oth er therapeutic options, nearly 2 yr later we decided to reperform I-13 1 measurements and scanning under hypothyroid conditions. All known me tastatic lesions this time showed intense I-131 uptake, more than 10-f old the previously measured values. High-dose I-131 treatment was rest arted.