Diffuse Goiter and Severe Hypothyroidism due to Metastasis to the Thyroid.

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 T(4) and T(3) 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.