Differential Diagnosis of Radiologically Diagnosed Thyroid Masses: Two Unusual Case Studies

Case 1 A 29 year old male, with no signifi cant past medical history, presented to his general practitioner after a lower respiratory tract infection. On examination a goitre was noted. Chest x-ray demonstrated a right upper mediastinal mass with marked tracheal deviation to the left (Fig. 1a). Computed tomography (CT) scan of the neck (Fig. 1b and 1d) was interpreted as an enlarged right lobe of the thyroid (80 × 52 × 44 mm) with retrosternal extension and also a suggestion of an enlarged left submandibular gland (Fig. 1c and 1d). Ultrasound scan confi rmed the right neck mass and reported it as enlargement of the right lobe of the thyroid gland with heterogenous echogenicity consistent with a multinodular goiter and a normal left lobe (Fig. 1e). Ultrasound guided fi ne needle aspiration (FNA) showed features consistent with multinodular goitre. At preoperative surgical review fi ve months later, the right sided goitre was confi rmed clinically; however enlarged left cervical nodes were noted. Neck ultrasound identifi ed a mass immediately lateral to the left submandibular gland (2.5 × 2.5 × 1.5 mm) felt to be consistent with an enlarged lymph node. Ultrasound guided FNA of this mass raised the possibility of thyroid tissue. A tentative diagnosis of thyroid carcinoma was made and the patient planned for total thyroidectomy, central lymph node dissection and left modifi ed radical neck dissection. At the initial left neck dissection, there were enlarged left upper jugular nodes (1–3 cm), and a normal left submandibular gland. In addition, there was a gray nodule straddled across the bifurcation of left common carotid artery consistent with a “carotid body tumour”, which is essentially a paraganglioma occuring at the carotid bifurcation. The thyroid gland was macroscopically normal. The apparent “right goitre” appeared to be a large paraganglioma. Histology revealed enlarged reactive left jugular nodes, normal thyroid, and bilateral paragangliomas with no evidence of malignancy.