Thyroid. 2008 Mar;18(3):369-71. [Link]

de Keizer B, Arsos G, Smit JW, Lam MG, Rinkes IH, Goldschmeding R, van Isselt JW.

Department of Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.


Focal I-131 accumulation is generally a reliable indicator of functioning normal thyroid tissue or a differentiated thyroid cancer metastasis. However, physiologic accumulation of activity may also be observed in organs such as the intestinal tract, liver, and salivary glands. Extrathyroidal I-131 accumulation has been reported in various sites, such as ectopic gastric mucosa, gastrointestinal and urinary tract abnormalities, cysts (mammary, liver, kidney, and ovaries), and inflammation and infection foci. We report a case of focal I-131 accumulation in a benign cystic mesothelioma in a patient with follicular thyroid cancer.