Axillary node metastasis from differentiated thyroid carcinoma with hürthle and signet ring cell differentiation. A case of disseminated thyroid cancer with peculiar histologic findings

Here we present a case of axillary lymph node metastasis in the context of disseminated differentiated thyroid cancer. The patient underwent near total thyroidectomy and neck and axillary lymph node dissection. A histopathological diagnosis of poorly differentiated follicular carcinoma with "signet ring cells" and Hürthle cell features was established. The patient received radioactive iodine therapy and TSH suppression therapy. Subsequently his serum thyroglobulin level decreased to 44.000 ng/ml from over 100.000 ng/ml.Currently there are only few reported cases of axillary node metastases from thyroid cancer, and to our knowledge, this is the first report on axillary lymph node metastasis from follicular thyroid carcinoma. "Signet ring cell" is a morphologic feature shared by both benign and, more rarely, malignant follicular thyroid neoplasm, and it generally correlates with an arrest in folliculogenesis. Our case is one of the rare "signet ring cells" carcinomas so far described.Differentiated thyroid cancer is usually associated with an excellent prognosis and indolent course. Distant metastases are rare events at the onset of thyroid cancer. Their incidence is about 4%, with an overall risk which is lowest for papillary thyroid cancers (2%) and highest for follicular (11%) and Hürthle cell carcinomas (12%) [1]. Among these presentations, metastasis to the axillary lymph nodes is even more unusual. It generally arises in the context of disseminated disease and carries an ominous prognosis [2]. Herein, we present the first ever reported case of axillary lymph node metastasis from follicular thyroid carcinoma. Interestingly this presentation was associated with peculiar histologic features described, so far, only in four other cases of follicular-derived thyroid carcinoma.A 65-year-old man was referred on April 2010 to our surgical department with histologically documented metastatic thyroid carcinoma on biopsy samples taken from a pathological fracture of his lef