RADIOIODINE BREAST UPTAKE IN NONBREASTFEEDING WOMEN - CLINICAL AND SCINTIGRAPHIC CHARACTERISTICS

We studied the scintigraphic and associated clinical characteristics o f radioiodine breast uptake in nonbreastfeeding thyroid cancer patient s undergoing routine whole-body radioiodine scanning, Methods: We perf ormed a retrospective review of the radioiodine scans and medical reco rds of 30 prospectively collected cases, Results: Twenty-three nonpreg nant patients had discontinued breastfeeding for a mean of 11.4 mo, Th ree postmenopausal and four single nulliparous patients had radioiodin e breast uptake on one or more occasions, This represented about 6% of all female patients who had radioiodine scans over a 3-yr period. Fou r patterns of uptake, full, focal, crescentic and irregular, were obse rved. Breast uptake mimicked lung metastasis in nine patients. Express ible galactorrhea and moderately elevated prolactin levels were presen t in 48% and 24%, respectively, of patients examined. In 14 patients f ollowed for an average of 11.4 mo, there were no consistent changes in the pattern or intensity of breast uptake. In 18 patients who had bot h I-123 diagnostic and I-131 postablation scans within a few days, bre ast uptake was present on both scans in 75%. In four patients, breast uptake was present, despite the 4%-9% radioiodine uptake by the thyroi d; in one patient, iodinated contrast material blocked the uptake of t he thyroid gland but not of the breast, Conclusion: Although the mecha nisms of radioiodine breast uptake remain unclear, breast uptake shoul d be suspected in all female patients with radioiodine uptake in the c hest area, even in the absence of a history of breastfeeding.