Primary thyroid lymphoma associated with metastatic thyroid tumor: discrimination with US.

ABSTRACT

We surgically treated a 75-year-old man who suffered from metastatic adenocarcinoma from the colon associated with primary thyroid lymphoma measuring 1 cm maximum in diameter. Radiologic findings were correlated with histopathology of excised specimens. Ultrasonography could discriminate between these two tumors based on the margin characteristics and the lesion echogenicity the metastatic tumor was shown as an ill-defined hypo to iso echoic mass, while the malignant lymphoma was detected as a well-defined markedly hypoechoic mass. In addition, we could confirm that early-stage primary thyroid lymphoma even as small as 1 cm shows the same radiologic appearance as that of a bulky lymphoma.