Metastasis from Thyroid Carcinoma
A 50-year-old woman presented with a painless lesion deep in the nail of the left little finger, which she had first noted 2 months earlier. There was no history of associated trauma or pruritus. The physical examination revealed a firm 2-cm lesion with a scab in the center (Panel A). The overlying nail was dystrophic and partially separated from the nail bed. Finger movements were normal. Radiography of the left fifth digit revealed a lytic lesion involving the terminal phalanx (Panel B, arrow). There was also diffuse enlargement of the thyroid gland, with a dominant nodule at the isthmus. Computed tomography of the chest showed an enlarged thyroid with retrosternal extension and a dominant nodule (Panel C, arrow), as well as multiple pulmonary nodules. Fine-needle aspiration of the thyroid nodule revealed a follicular neoplasm, and biopsy of the phalangeal lesion revealed metastasis from follicular thyroid carcinoma. The patient underwent total thyroidectomy. During radioiodine scanning, uptake was noted in the left little finger as well as in the choroid of the eye, thereby highlighting the iodophilic nature of these metastases. After radioiodine therapy, there was complete regression of the digital metastasis.
