Open Access18F-PET/CT imaging of metastasis to the thyroid gland: Imaging findings and effect on patient management
Author(s) -
Giovanni G. Millare,
Michael Kwon,
Beth S Edeiken-Monroe,
J. Matthew Debnam
Publication year - 2017
Publication title -
journal of solid tumors
Language(s) - English
Resource type - Journals
eISSN - 1925-4075
pISSN - 1925-4067
DOI - 10.5430/jst.v7n2p7
Subject(s) - medicine , thyroid , malignancy , metastasis , thyroid cancer , radiology , nuclear medicine , cancer , pathology
Purpose: While metastasis to the thyroid from a primary cancer remote to the thyroid is uncommon, current imaging techniqueshave improved detection of these intrathyroid metastases. The purpose of this study was to evaluate the 18F-PET/CT appearanceof intrathyroid metastases and assess the impact of detection on patient management.Methods: The 18F-PET/CT appearance of intrathyroid metastasis, including standardized uptake value (SUV), disease extent,and the effect on patient management following diagnosis were retrospectively reviewed. Inclusion criteria included 18F-PET/CTimaging and diagnosis of the intrathyroid metastasis matching the remote primary tumor.Results: Intrathyroid metastasis were detected in 24 patients. The intrathyroid metastases presented on 18F-PET/CT as focalnodular uptake (n = 21), multiple nodular uptake (n = 2), or diffuse uptake/infiltration of the thyroid gland (n = 1). The SUVranged between 3.9 and 42 (median 12.5 ± 7.5); in 2 patients, the FDG-avidity was minimal. On 18F-PET/CT, distant metastaseswere present outside the neck (n = 18), or limited to the neck (n = 6). In 2 of these 6 patients, the thyroid was the only site ofmetastatic disease. Due to the metastatic disease, the therapy was changed in 23 of 24 patients; 1 patient was lost to follow-up.Conclusion: In any patient with a previous or current history of an extrathyroid malignancy, an 18FDG-avid thyroid mass ordiffuse infiltration of the thyroid on 18F-PET/CT should be considered a potential intrathyoid metastasis until proven otherwise.Knowledge of an intrathyroid metastasis may impact patient management, especially if the thyroid or neck are the only sites ofmetastatic disease.