Endocrine Abstracts

Introduction: Aggressive forms of papillary thyroid carcinoma are more commonly observed; anaplastic and poorly differentiated types are rarer, but have a higher death rate. The transformation from papillary to anaplastic is a rare occurrence; it is even more uncommon for a small region of well-differentiated thyroid cancer to occur alongside the anaplastic form in metastatic lymph nodes.

Aim: We present a case of an aggressive form of papillary thyroid carcinoma – a tall cell variant, with demonstrated dedifferentiation to anaplastic carcinoma.

Case report: The 63-year-old female patient presented in our clinic for respiratory difficulties and dysphonia, associating a large goiter. The imaging tests demonstrated a large nodular goiter with compressive effects and the biological profile was within normal limits. The patient underwent a total thyroidectomy with bilateral lymphadenectomy. Eight metastatic lymph nodes and a tall oxyphilic variant of papillary carcinoma with soft tissue invasion were described by the histological examination. The patient was responsive to high doses of radioiodine therapy; whole-body scintigraphy showed an iodine-sensitive rest of the thyroid tissue, with high level of stimulated thyroglobulin and anti-thyroglobulin antibodies. One year after the diagnosis, the scintigraphy and the CT scan were negative, and the biological profile revealed a decreasing level of thyroglobulin and anti-thyroglobulin antibodies. After few months the patient relapsed, with large metastatic lymph nodes in the cervical and mediastinal compartment and pulmonary nodules suggesting distant dissemination on CT scan, decreasing level thyroglobulin and normal anti-thyroglobulin antibodies. The thyroid origin was confirmed after biopsy. The whole-body scintigram was negative, suggesting a resistant form to radioiodine treatment. We start treatment with tyrosine-kinase inhibitor without positive response. She underwent the second surgery for the large compressive lymph nodes in cervical compartment. The histopathologic exam with immunochemistry revealed small areas of papillary thyroid carcinoma – tall cells variety and predominant anaplastic carcinoma, with positive staining for MCK, TTF1, PAX8, Thyroglobulin being positive in isolated cells, and a 35% positive Ki67 in the tumor cells with solid pattern. The patient needed tracheostomy for bilateral cords paralysis. Her option was for palliative care.

Conclusion: Involved lymph nodes in papillary thyroid cancer increase the risk of recurrence, but usually do not change the prognosis. In the exceptionally cases the progression to anaplastic carcinoma is the most feared complication, with fatal outcome. The simultaneous occurrence of papillary and anaplastic thyroid carcinoma in the metastatic lymph node, along with radio-iodine resistance and a decreasing level of thyroglobulin, the rapid and poorly evolved metastasis affecting vital structures and the ineffectiveness of treatment are proofs of the dedifferentiation.