Endocrine Abstracts

Introduction: Anaplastic thyroid carcinoma is a subtype of thyroid carcinomas with an aggressive form. Anaplastic thyroid carcinomas are thought to develop as a result of differentiation of well-differentiated thyroid cancers. Anaplastic transformation of well-differentiated papillary thyroid carcinoma is very rare and most commonly occurs in thyroid gland and regional lymph nodes, whereas occurrence at distant metastatic site is extremely rare. Here we report the case of a patient with papillary thyroid carcinoma presenting with anaplastic transformation of metastases in the lung.

Case Presentation: An 80-year-old man presented with a 1 week history of dyspnea. His medical history included hypertension and papillary thyroid carcinoma, stage PT3N1bM0, for which he underwent total thyroidectomy, santral and lateral neck dissection and received radioactive iodine (RAI) therapy in 2008. 2 years ago, the patient was re-operated for recurrent disease and received second time RAİ therapy. Post-RAI scintigraphy was detected no involvement. Thyroglobulin and anti-thyroglobulin values were negative after RAI therapy. There was no metastasis in the thorax computed tomography (CT) imaging during this period. The patient; who did not come to follow up for 2 years, thorax CT was performed due to shortness of breath. Thorax CT scan showed metastatic nodules, the largest of nodules which 2.4 cm diameter in the lung and tissue densities compatible with recurrence including cystic necrotic areas extending to the pretracheal, right paratracheal, upper mediastinum in the thyroid gland lodge. Laboratory tests revealed TSH:0.94 mU/l (normal 0.27-4.2 mU/l) thyroglobulin:0.52 mg/l (normal 3.5-77 mg/l) anti-thyroglobulin antibody: 14 (normal 0-115 U/ml). Biopsy was performed from the mass in the thyroid lodge and the nodule in the lung. Histologic examination of thyroid mass and lung nodule revealed anaplastic thyroid carcinoma. Immunohistochemical staining for markers showed the presence of paired-box gen 8 (PAX-8) and absence of transcription factor 1 (TTF-1), and thyroglobulin (Tg). Tracheostomy was performed due to tracheal compression. Despite supportive treatment, his condition kept deteriorating and he was followed up in the intensive care unit. Subsequently, the patient died on the 15 th day of hospital admission.

Conclusions: We have described a case of anaplastic transformation of thyroid papillary carcinoma in the lung metastases, 14 years after initial presentation of papillary thyroid carcinoma. Anaplastic transformation of thyroid papillary carcinoma is a rare entity. It should be kept in mind that it can be seen with metastases years after diagnosis and considered in cases with aggressive clinical course.