Cutaneous thyroid carcinoma sixteen years after benign total thyroidectomy: a unique case.

backgroundCutaneous metastasis of papillary thyroid carcinoma is rare and is a hallmark of a locally aggressive tumor. CASE REPORT: We present a unique case of cutaneous thyroid carcinoma sixteen years after total thyroidectomy for multi-nodular goiter. The tumor originated from the upper anterior thoracic wall's skin and was found to invade the rostral half of the sternum's external periosteum and the caudal part of the right sternocleidomastoid muscle. Wide local excision of the neoplasm was performed with macroscopically free margins and right selective neck dissection (lymph node levels IV and V). The skin deficit was reconstructed with a right pectoralis major island flap. The histopathologic findings displayed a papillary thyroid carcinoma with Hürthle cell predominance and microscopically positive margins at the excised portion of the sternocleidomastoid muscle. The patient was placed on close follow-up, and nine months postop, there are no clinical signs of recurrence.

conclusionTo our knowledge, this is the first case of cutaneous thyroid carcinoma following benign thyroidectomy. A possible mechanism for this incidence is the malignant transformation of benign thyroid cells inoculated into the skin. Dissecting along the fascial planes during thyroidectomy and preserving the thyroid capsule establishes a clean surgical field and minimizes the chance of inoculation of thyroid cells into the adjacent structures. Close follow-up and a high level of suspicion for skin lesions in patients with thyroid disease are warranted in all cases. HIPPOKRATIA 2020, 24(2): 88-90.