Resumen

PACENZA, NA; GROPPO, N  y  GUIBOURG, HC. Association of Papillary Thyroid Carcinoma and Graves' Disease: Unexpected Development and Efficiency of Ablative Dose with Recombinant Human Thyrotropin (rhTSH). Rev. argent. endocrinol. metab. [online]. 2013, vol.50, n.1, pp.35-41. ISSN 1851-3034.

Introduction: Differentiated thyroid cancer (DTC) associated with Graves' disease (GD) is a relatively rare disease, occurring in 0.3 % to 9.8 % of GD patients. Some studies suggest an increased aggressiveness of DTC in GD patients, apparently related to thyroid stimulating antibodies. We report the case of a patient with DTC and GD, describing his peculiar evolution. Case report: 22-year-old male who presented with obesity. History of a cousin with DTC and grandmother and mother with goiter. Physical examination: Weight: 116.4 kg, height: 1.73 m, BMI: 38.9. Clinically euthyroid. Thyroid palpation was difficult due to his thick neck. Initial analysis: T3, T4 and TSH within normal range. Thyroid ultrasound (US) showing 11 x 10 mm hypoechoic nodule in right lobe (RL). US-guided fine-needle aspiration (FNA) was requested. Four months later, the patient returned with clinical symptoms of hyperthyroidism (diarrhea, palpitations, insomnia, tremors, cramps and difficulty walking). Laboratory: T3: 557 ng/dl, T4: 18.8 mcg/dl, FT4: 3.73 ng/dl, TSH <0.01 μIU/mL, TPOA: 186 IU/mL, TGA: 965 IU/mL. US-guided FNA: "Cytological findings are related to papillary thyroid cancer". Thyroid Scan: "Diffuse enlargement of the gland, "warm" nodule in RL". 131I uptake was: 1st hour: 12 %, 24 hours: 58 %. He received methimazole 20 mg daily. He was operated on 2 months later ("total thyroidectomy"). Pathology: "Follicular variant of papillary thyroid carcinoma in right lobe and classical variant of papillary carcinoma in area of the left lobe". Thirty-five days after surgery (S) (without levothyroxine): TSH <0.01 μIU/mL, Tyroglobulin (Tg) 32.1 ng/mL. Sixty days after S: TSH <0.1 μIU/mL, FT4 1.2 ng/dL, T3 1.3 ng/dL. Clinically euthyroid with normal neck palpation. Chest Computed axial tomography (CT): "Normal". US of the neck: "Bilateral thyroid lodge is free". Ninety days later: TSH 0.32 μIU/mL, TRAb 29 % (normal: until 15 %). Thyroid Scan with 99mTc pertechnetate: "Pathological uptake in middle and lower cervical region right and left lower neck." He was reoperated on 4 months after his initial S: "Resection of epithelial proliferation with thyroid aspect in superior mediastinum region". Pathology: "Node with extensive infiltration of neoplastic proliferation of follicular variant of papillary carcinoma with areas of connective tissue infiltrated periganglionar of papillary thyroid cancer". Lab 40 days after the second surgery: TSH 2.3 μIU/mL, FT4 0.82 ng/dL, Tg 4.7 ng/mL. Neck and chest CT showed neither pathological lesions nor lymphadenopathy. 131I uptake with 7.4 MBq was: 1st hour: 8 % and 24 hours: 12 %. Neck Scan: "Multiple areas of tracer fixation in the neck". No pathological signs on neck palpation. Ablative dose of 7.4 GBq of 131I was performed to the patient, previously using rhTSH (two doses of 0.9 mg), reaching TSH >100 μIU/mL. Scan post ablative dose: "Important focus on right paratracheal region." Neck MRI showed: "Absence of thyroid gland. Rounded image of about 10 mm at right paratracheal level". The patient initiates suppressive therapy with levothyroxine (LT4). Six months after ablation therapy (without LT4): TSH >100 μIU/mL, Tg: 13.8 ng/mL, TGA: 431 IU/mL. Body Scan with 2 mCi: "Pathological focus of radioiodine behind the right sternoclavicular joint". New neck MRI: "Image in right pretracheal region smaller than the previous study". The patient received 5.55 GBq of 131I. The same radioiodine treatment was repeated 8 months later. At present, 4 years after the patient's initial surgery, he is in good general health, performing his normal activities, with TGA in sharp decline, negative 131I body scan and without signs of persistent or recurrent disease. Conclusions: We report a case of follicular variant papillary TC associated with GD with concomitant development of hyperthyroidism, with positive TGA, in a 22-year-old obese man. Highlights: 1) The importance of initial US exploration in a patient with GD, 2) Residual neoplastic lymph node tissue after 2 S, performed by an experienced surgeon, with enough functioning tissue to prevent a significant elevation of TSH and allow 131I ablative therapy, 3) Tumor local aggressiveness shown by adjacent tissues and lymph node infiltration, 4) Failure to identify residues in the neck by CT and US; instead, effectiveness of the neck MRI without contrast and 99mTc thyroid scan, 5) Effective use of ablative radioiodine therapy with rhTSH.

Palabras clave : Hyperthyroidism; Papillary thyroid carcinoma; Graves' disease; TGA; rhTSH.

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