"Bulky mass": metastasis of poorly differentiated follicular thyroid carcinoma: a case report.

Poorly differentiated follicular thyroid carcinoma (PDFC) is a tumor of follicular cell origin with intermediate attributes between well-differentiated carcinomas and anaplastic carcinomas. The majority of patients presenting with distant metastases have locally advanced tumors, being lungs and bones the most common sites affected. We present a case of a patient with a painful bulky mass at the left thorax-abdominal wall as an uncommon distant metastasis of a PDFC. After thyroidectomy, a pre-ablative 131I whole-body scan showed distant metastases on the neck, both lungs, and lateral chest-abdominal wall, so the administration of I for thyroid remnant ablation stimulated with RH-TSH was decided.