Bone Metastasis as the Primary Presentation of Follicular Thyroid Carcinoma

  • Follicular thyroid cancer-FTC is the second most common type of thyroid cancer. It is considered a well differentiated tumor, however there is a risk of invasion and spread. Between 4-20%  of cases of FTC have metastasis upon primary presentation. Metastasis occurs most commonly to the bones and lungs. In addition, although rare,  there have been cases reported of the metastatic foci producing thyroid hormones, making patients hyperthyroid.
     
    This is a case of a 45 year old female, who initially presented to her primary physician with a 9 month history of right shoulder pain and swelling. Initial x-ray of her right shoulder showed a large destructive bone lesion at the lateral border of right scapula, likely representing a neoplastic process. Further investigation with CT also showed multiple lung nodules and a heterogeneously enhancing right thyroid nodule with calcifications. Laboratory studies showed overt hyperthyroidism.  Ultrasound of the thyroid gland showed a complex right thyroid nodule measuring 1.7cm and an isoechoic left thyroid nodule measuring 1.6cm. Fine needle aspiration revealed a follicular neoplasm in the right side. Ultrasound guided biopsy of the right shoulder confirmed metastatic thyroid follicular carcinoma.
     
    This report is an example of follicular thyroid carcinoma with a primary presentation of metastatic disease in the bone. It serves as a reminder that patients with imaging suggestive of neoplastic disease in the bone or lung, a primary thyroid malignancy should be considered, even without any symptoms suggestive of thyroid nodules, and workup should be done promptly to identify this and begin treatment.

 

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