Spindle epithelial tumor with thymus-like differentiation of the thyroid.

Spindle epithelial tumor with thymus-like differentiation (SETTLE) of the thyroid is a rare tumor that occurs habitually in children and young adults. To date, about 20 cases of SETTLE have been reported in the English medical literature. It is considered to be a tumor of low malignancy with a favorable outcome, but delayed blood-borne metastases have been reported (sometimes over 20 years after initial treatment). In the current report, the authors describe an interesting case of SETTLE in a young woman. Double phase Tc-99m tetrofosmin scintigraphy showed accumulation of the tracer in the thyroid mass.