Diffuse Goiter and Severe Hypothyroidism due to Metastasis to the Thyroid

Abstract

Despite the fact that the thyroid is a highly vascularized organ, clinically significant metastatic spread to the thyroid is considered uncommon. Hypothyroidism due to these metastases seldom occurs. A 68-year-old female patient came to our department because of rapid enlargement of the lower anterior part of the neck, which developed within 2 months. She had a history of poorly differentiated esophageal adenocarcinoma diagnosed 4 years ago, for which she underwent surgical removal of the neoplasm and received three cycles of chemotherapy. On physical examination, the clinical diagnosis was hypothyroidism with large, diffuse, firm goiter, and enlarged firm and fixed cervical lymph nodes. Thyroid and cervical ultrasound examination revealed significant diffuse enlargement of the thyroid, which was heterogeneous and hypoechogenic without focal lesions and multiple pathologically enlarged cervical lymph nodes. Laboratory examination revealed increased TSH levels with decreased free T₄ and T₃ levels. Fine needle aspiration biopsy of the thyroid revealed a metastatic adenocarcinoma. Our patient received external beam radiation therapy and chemotherapy, but unfortunately she passed away 4 months after diagnosis. Therefore, in case of a new (focal or diffuse) lesion in the thyroid gland in a patient with a history of malignant disease, regardless of the time elapsed since the diagnosis of the primary neoplasm, relapse of the preexisting disease must be considered until proven otherwise.

Diffuse Metastasis to the Thyroid: Unique Ultrasonographic Finding and Clinical Correlation

“…Previous reports of ultrasonographic findings of thyroid metastases demonstrated single or multiple hypoechoic nodules with ill-defined margins and intranodular vascularization without evidence of microcalcification ( 6 , 12 ). Although there have been a few reports of diffuse thyroid metastasis in which patients had abnormal thyroid function ( 13 , 14 , 15 ), the ultrasonographic findings of diffuse metastases were not established in these cases. Miyakawa et al ( 15 ) reported diffuse thyroid metastasis from lung cancer, which showed diffuse thyroid enlargement with inhomogeneous and hypoechoic internal architecture; the sonographic appearance in their case report was similar to our findings in our series of patients.…”

“…Abnormal thyroid function can be observed in metastatic thyroid cancer ( 13 , 14 , 21 , 22 ). Diffuse infiltration of cancer cells induces hypothyroidism ( 8 ) and, in rare cases, temporary thyrotoxicosis when destruction of the thyroid gland occurs with leakage of stored thyroid hormone into the peripheral blood ( 6 , 21 , 22 ).…”