CLINICS 2011;66(12):2177-2178 CASE REPORT DOI:10.1590/S1807-59322011001200027 Thymic hyperplasia in Graves’ disease Debora Lucia Seguro Danilovic,I Regina Matsunaga Martin,II Pedro Caruso,III Suemi MaruiII I Hospital das Clı´nicas da Faculdade de Medicina da Universidade de S a˜o Paulo, Unidade de Tireoide, Endocrinology and Metabolism Department. S a˜o Paulo/SP, Brazil. II Hospital das Clı´nicas da Faculdade de Medicina da Universidade de S a˜o Paulo, Endocrinology and Metabolism Department, S a˜o Paulo/ SP, Brazil. III Hospital das Cl´ınicas da Faculdade de Medicina da Universidade de S a˜o Paulo, Pneumology Department, S a˜o Paulo/SP, Brazil. Email: suemimar@usp.br Tel.: 55 11 30617253 CASE DESCRIPTION Over the last year, a 40-year-old man had complained of weekly episodes of facial flushing, diaphoresis, irritability,and diarrhea, which were triggered by emo- tional stress or exercise. He also presented with chest discomfort and had lost 6 kg. He had poorly controlled essential hypertension that had lasted over the last six years. On examination, his systolic blood pressure was 160 mm Hg, his diastolic blood pressure was 110 mm Hg, his heart rate was 110 beats/min, and his body mass index was 32 kg/m2; he did not present with postural hypotension. A small goiter without nodules and a slight lid retraction were noted. He had no facial flushing or hand tremor. During the chest discomfort investiga- tion, the chest X-ray revealed an anterior mediastinal enlargement. A thoracic computed tomography (CT) scan revealed a homogeneous mass with no adjacent structure invasion or calcification at the topography of the thymus enlargement (Figure 1A). Goiter was also detected but did not extend to the intrathoracic compartment. A carcinoid syndrome caused by a primary neuroendocrine tumor was sus- pected. The patients exams depicted normal values of urinary 5- hydroxyindoleacetic acid (2.8 and 3.1 mg/24 h, normal values-NV 2-6), urinary metanephrines (1.0 and 0.09 mcg/ mg creatinine, NV ,1.2), serum calcitonin (7.3 pg/mL, NV ,11.5), negative tumoral markers b-hCG and alpha-feto- protein. Thyrotoxicosis was diagnosed from the following fluoroimmunoassay measurements: total T3, 371 ng/dL (NV 40–180 ng/dL); total T4, 20.9 mcg/dL (NV 4.5– 12 mcg/dL); free T4, 4.9 ng/dL (NV 0.7–1.5 ng/dL); and a suppressed TSH,0.03 mUI/L (NV 0.4–4.5 mUI/L). Serum antiperoxidase and antithyroglobulin antibodies measured by fluoroimmunoassay were positive (859 and 72 U/mL, NV,35 U/mL), with levels of TSH-receptor antibody (TRab) of 49% (radioimmunometric assay NV,8%). Ultra- sound thyroid imaging revealed a 43.2 g homogeneous hypoechogenic goiter, which did not have nodules and was limited to the neck. Copyright 2011 CLINICS – This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. No potential conflict of interest was reported. 2177 Therefore, Graves’ disease was diagnosed, and a thymus growth was then attributed to hyperplasia caused by Graves’ disease. Methimazol (20 mg/day) was initiated, and after four months of treatment, symptoms had improved, and thyroid hormones had normalized. Goiter and TRab values had reduced. After six months of thyroid hormonal control, a new CT revealed marked thymus shrinkage (Figure 1B). After 24 months, the patient was in remission of Graves disease, with negative TRab values and a normal thoracic CT scan. Graves ophthalmopathy was never presented. DISCUSSION We described a patient with systemic arterial hyperten- sion and thoracic discomfort that presented an anterior mediastinal mass and Graves disease. In adults, thymoma is a common neoplasm of the anterior mediastinal compart- ment and occurs between 40 and 60 years of age with a slightly male predominance. Chest discomfort or pain is the most common symptom. However, our patient also presented episodic flushing, diaphoresis, and diarrhea, which are common symptoms for carcinoid syndrome. Together with the anterior mediastinal enlargement, carcinoid syndrome that had resulted from a neuroendocrine tumor was initially suspected. Primary neuroendocrine tumors of the thymus account for less than 5% of all anterior mediastinal neoplasms. They are highly aggressive and more prevalent in men during the fourth and fifth decades of life. The symptoms are related to structure compression, distant metastasis, or endocrinopathies, including carcinoid syn- drome. A CT-scan usually shows a lobulated thymic mass with heterogeneous enhancement and central areas of low attenuation, before necrosis and hemorrhage, and even- tually calcifications.1 The presence of normal 24-hour urinary vanillylmandelic acid and metanephrine levels ruled out the possibility of neuroendocrine tumors. Normal testing physical examination and undetectable alpha- fetoprotein and beta human chorionic gonadotropin levels also ruled out the possibility of nonseminomatous germ- cell tumors.1 Combining the hormonal thyroid abnormalities with the thoracic CT characteristics, thymic hyperplasia due to Graves disease was diagnosed. Thymic hyperplasia is commonly associated with Graves’ disease, but it is not emphasized in major endocrinology texts and must be recognized by all physicians.