Non-Hodgkin's lymphoma in a patient with follicular thyroid cancer: the role of 99mTc-methoxy isobutyl isonitrile imaging.

In the post-surgical follow-up of a patient with follicular thyroid carcinoma, a palpable mass in the left supraclavicular region was highly indicative of metastatic disease. Technetium-99m methoxy isobutyl isonitrile (99mTc-MIBI) showed an increased but heterogeneous uptake within the lesion. Surprisingly, a different neoplastic disease was histologically demonstrated. Lymph node abnormalities due to non-Hodgkin's lymphoma rather than metastatic thyroid disease were demonstrated. In conclusion, non-Hodgkin's lymphoma may occur in patients with follicular thyroid carcinoma. This new lesion significantly concentrated 99mTc-MIBI. Thus, the results of 99mTc-MIBI imaging have to be carefully evaluated during the follow-up of patients with thyroid cancer.