Endocrine Abstracts

Case history: A 62 years old lady presented with a history of weight loss, sweating, and tremor for 3 months. The diagnosis of thyrotoxicosis was made following biochemical confirmation and she was started on carbimazole 20 mg twice a day. Several weeks later she got admitted with progressive shortness of breath, hoarseness of voice, and a painful neck lump. Examination revealed a firm to hard fixed multinodular goiter with a dominant hard nodule at the left upper pole. There was an enlargement of deep cervical lymph nodes in the left anterior triangle. She had a fine tremor, tachycardia with no features of Grave’s ophthalmopathy.

Investigations: The initial thyroid function tests revealed thyroid-stimulating hormone (TSH) of 0.09 miu/l (0.4–4.2) free T4 31.5 pmol/l (10–28.2), free T3 8.24 pmol/l (4.26–8.1) and negative Thyroid receptor antibodies. At the time of admission which was 8 weeks following anti-thyroid medications, she remained toxic with a TSH of 0.085 miu/l, free T4 32 pmol/l, free T3 7.8 pmol/l. Tc99m thyroid uptake scan showed low uptake in the thyroid gland with markedly reduced uptake over a left upper pole. USS revealed a multinodular goiter invading into the trachea with a heterogeneous nodule of 2.8 x 3 cm with a hypoechoic rim, increased internal vascularity, and Intralesional microcalcifications. There was ultrasound evidence of background thyroiditis. Fine needle aspiration cytology of the suspicious nodule revealed marked cellular atypia suggestive of poorly differentiated thyroid carcinoma. Chest X-ray revealed multiple cannonball opacifications in bilateral lung fields evident of lung metastasis.

Results and treatment: The multidisciplinary team decided that the surgical debulking of the tumor was not beneficial at this late stage of malignancy. The patient declined any further tests and agreed with palliative management. She was given adequate pain relief and a tracheostomy was performed to support breathing. Her clinical condition deteriorated leading to severe upper airway obstruction. She was started on high-dose steroids and Radiotherapy was planned, however, she passed away after 6 days of admission.

Conclusions and points for discussion: In differentiated thyroid malignancy, thyrotoxicosis is usually due to excessive hormone secretion from functioning cancer cells whereas infiltration causing follicle destruction or nonspecific thyroiditis are the proposed mechanisms in poorly differentiated malignancy. Thyroid malignancy presenting with thyrotoxicosis is a rare occurrence where a high degree of clinical suspicion and early histological evaluation is essential.