Secondary thyroid malignancy – a rare clinical finding?

Abstract

Metastases to the thyroid gland, while rarely seen in clinical practice, can pose a diagnostic and therapeutic challenge. Most commonly, they originate from lung, renal, and breast cancer, and are generally a sign of multiorgan metastatic disease. In most cases, metastases to the thyroid gland are diagnosed incidentally on imaging studies, since they are rarely symptomatic and often do not influence thyroid function tests. Thyroid ultrasonography and fine-needle aspiration biopsy play a pivotal role in their evaluation, as both classic immunocytochemical features, and more novel molecular markers can help in the differential diagnosis. Prognosis mainly depends on the biology of the primary tumor and its extension. Communication between clinicians is essential in such patients, in order to ensure that the treatment options are carefully balanced, thus raising the need for multidisciplinary teams in their management.

Aliens in the thyroid gland: The secondary lesions

“…Thyroid function tests are less frequently deranged hence thyroid function tests have limited diagnostic utility. Initial hyperthyroidism has been reported in a few patients with secondary lesions 4 . The patients in the current series were found to be euthyroid.…”

“…The thyroid secondary lesions are associated with aggressive neoplasms and a high tumor burden. A higher incidence of 24% was reported in the autopsy studies performed in patients with widespread metastases 4 . In clinical settings, the most common primary tumor to metastasize to the thyroid gland is Renal cell carcinoma while in autopsy studies a pulmonary primary is more common 5 .…”

“…In clinical settings, the most common primary tumor to metastasize to the thyroid gland is Renal cell carcinoma while in autopsy studies a pulmonary primary is more common 5 . The thyroid secondary lesions are often metachronous in presentation as they are rarely symptomatic and are seldom evaluated in the initial diagnostic workup of the primary lesion 4 . With the availability of high‐resolution imaging for the staging of cancer patients, a greater number of thyroid secondaries are being detected.…”

“…The thyroid secondary lesions are often metachronous in presentation as they are rarely symptomatic and are seldom evaluated in the initial diagnostic workup of the primary lesion. 4 With the availability of highresolution imaging for the staging of cancer patients, a greater number of thyroid secondaries are being detected. We have attempted to evaluate the secondary lesions of the thyroid gland diagnosed by Fine needle aspiration cytology (FNAC).…”

Metastases to the thyroid gland: ultrasonographic findings and diagnostic value of fine-needle aspiration cytology

“…Despite the rich blood supply of the thyroid, the low incidence of MTTG is quite surprising ( 18 ). It may be attributed to the fast blood flow throughout the thyroid gland and the high concentration of oxygen and iodine, inhibiting the growth of malignant cells ( 19 ).…”