Endocrine Abstracts

Introduction: Poorly differentiated thyroid carcinoma is a tumor of follicular origin with morphological and biological characteristics between anaplastic and well differentiated carcinoma. It accounts for less than 5% of all thyroid tumors and is characterized by adverse prognosis, aggressive behavior and frequently distant metastases, mainly to lungs and bones and to a lesser extent to brain, liver, kidney, breast and skin. Incident presentation: We report a case of a patient with poorly differentiated thyroid carcinoma, that during the progression of the disease presented a left orbital mass, a rare site of metastasis. The patient at 48 years of age was subjected to total thyroidectomy and histology revealed a poorly differentiated follicular thyroid carcinoma of the left lobe, 5.6 cm in diameter with capsular and vascular infiltration. The patient received 100 mCi I131 and TSH suppressive therapy was prescribed. Three years later the first relapse of the disease was presented with cervical lymph nodes metastasis, and during the upcoming 6 years metastases were appeared in cervical lymph nodes, lung and lateral abdominal wall. The treatment included, as far as possible, surgical removal of accessible lesions and administration of I131 (total 825 mCi). During the progression of the disease, due to the increased thyroglobulin and negative WBS, PET/CT was performed which revealed pathological uptake in two lung nodules, as well as in a cervical lymph node. Tyrosine kinase inhibitor was prescribed. Two years later, MRI revealed a lesion in the left orbit, 1.5 cm in diameter. Complete surgical removal of the lesion was performed, and histology revealed a metastatic thyroid carcinoma of low differentiation (negative thyroglobulin expression). The patient showed progress of the disease under TKI treatment.

Conclusion: Secondary localization of thyroid carcinoma in the orbit is extremely rare and almost always occurs in patients with long history of malignancy and widely spread disease. Therapeutic options are tumor removal, external radiation, brachytherapy, radioactive iodine, targeted therapies, and if eye loss is occurred, surgical excretion of the eye is recommended.