Endocrine Abstracts

Background: Papillary thyroid cancer (PTC) is the most common type of thyroid carcinoma, but it rarely presents as an intrathoracic mass with concurrent hyperthyroidism due to Graves disease.

Case presentation: A 73-year-old man presented with weight loss. Imaging by computed tomography (CT) documented a large mediastinal mass in the infrathyroidal space separate from the thyroid gland and pulmonary lesions suggestive of metastases. Neck ultrasound showed two spongiform nodules in the right lobe of the thyroid gland, with a benign and non-diagnostic citology. A few months later, the patient refers significant weight loss, palpitations and hand tremors. Blood tests identified overt hyperthyroidism (TSH <0.02 μUI/ml, T4L 3.86 ng/dl, T3L 9.2 pg/ml). He was then referred to our center for diagnostic evaluation. Endobronchial ultrasound-guided needle biopsy of the mediastinal mass was compatible with metastasis from PTC with thyroglobulin in the washout of the needle above 30.000 ng/ml. 99 m Pertechnetate scintigraphy showed increased diffuse uptake in the thyroid parenchyma and absence of uptake in the paratracheal mass and in the lung nodules. Further study of the hyperthyroidism revealed a Graves disease (TRAB 21.9 UI/l). At this time CT was repeated, showing significant growth of the mediastinal mass with tracheal invasion and mediastinal vessels infiltration. For this reason, the patient was not considered for surgical intervention and is waiting for palliative radiotherapy.

Conclusions: The association between PTC and Graves disease is infrequent. Furthermore, this case highlights the importance of obtaining a histological examination of an intrathoracic mass, in order to ensure an early diagnosis and treatment.