Rare metastases of differentiated thyroid carcinoma: pictorial review

Abstract

Differentiated thyroid cancer (DTC) is usually indolent with good prognosis and long-term survival. However, DTC distant metastasis is often a grave event and accounts for most of its diseasespecific mortality. The major sites of distant metastases are the lung and bone. Metastases to the brain, breast, liver, kidney, muscle, and skin are rare or relatively rare. Nevertheless, recognizing rare metastases from DTC has a significant impact on the clinical decision making and prognosis of patients.131 I single photon emission computed tomography/computed tomography ( 131 I-SPECT/CT) can provide both metabolic and anatomic information about a lesion; therefore, it can better localize and define the 131 I-WBS findings in DTC patients. In this pictorial review, the imaging features of a range of rare metastases from DTC are demonstrated, with a particular emphasis on the 131 I-SPECT/CT diagnostic aspect.

Diagnostic clue of nodular fasciitis mimicking metastasis in papillary thyroid cancer, mismatching findings on 18F-FDG PET/CT and 123I whole body scan: A case report

“…The majority of thyroid cancers are localized at the time of diagnosis with only a small proportion (10-35%), depending on the histology, presenting with distant metastasis (7,8). This proportion is only 4-15% in the case of differentiated thyroid cancers (7,8).…”

Adrenal metastasis from differentiated thyroid carcinoma documented on post-therapy131I scan: A case based discussion

“…Most of the reported cases of adrenal metastasis were asymptomatic, as was observed in our case [6][7][8][9][10][11] . Such adrenal metastatic lesions in the setting of differentiated thyroid carcinoma are quite rare [12][13][14][15][16][17] . These metastases are generally associated with lung and skeletal metastases and their detection is difficult even if they are iodine concentrating owing to their proximity of the physiological uptake of radioiodine in the gut or their excretion route through kidney.…”

“…The most common mode of spread of FTC is by vascular invasion with metastases commonly seen in the skeletal system and lungs. However, there have been occasional reports of metastases to other soft tissue such as the brain, kidneys, liver and adrenals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] .…”

FDG PET/CT in the Detection of Pancreatic Metastasis in a Patient with Follicular Thyroid Carcinoma and Negative I-131 Whole Body Scan Findings

“…While FTC usually remains localized to the thyroid gland, distant metastasis is observed in a minority of patients, with a reported incidence ranging from 4% to 15% (1)(2)(3). Metastatic FTC significantly contributes to disease morbidity and has been found to be associated with a 10-year survival of 40-45% (2).…”

“…FTC metastasizes most commonly to the lungs and bones (5). Other sites of distant metastasis are rare or relatively rare and include the brain, breast, liver, kidneys, muscle and skin (3,6). However, metastatic FTC extending to the pancreas has not been previously reported.…”