IgG4-related Hashimoto’s thyroiditis – A new variant of a well known disease / Tireoidite de Hashimoto associada a IgG4 – Uma nova variante de uma doença bem conhecida

Hashimoto’s thyroiditis (HT) has been characterized for many years as a well-defined clinicopathologic entity, but is now considered a heterogeneous disease. IgG4-related HT is a new subtype characterized by thyroid inflammation rich in IgG4-positive plasma cells and marked fibrosis. It may be part of the systemic IgG4-related disease. We report a case of a 56-year-old Portuguese man who presented with a one-month history of progressive neck swelling and dysphagia. Laboratory testing revealed increased inflammatory parameters, subclinical hypothyroidism and very high levels of thyroid autoantibodies. Cervical ultrasound (US) demonstrated an enlarged and heterogeneous thyroid gland and two hypoechoic nodules. US-guided fine needle aspiration cytology was consistent with lymphocytic thyroiditis. The patient was submitted to total thyroidectomy and microscopic examination identified typical findings of HT, marked fibrosis limited within the thyroid capsule and lymphoplasmacytic infiltration, with >50 IgG4-positive plasma cells per high-power field and an IgG4/IgG ratio of >40%. After surgery, serum IgG4 concentration was high-normal. Symptoms relief and reduction in laboratory inflammatory parameters were noticed. Thyroid function is controlled with levothyroxine. To our knowledge we report the first case of IgG4-related HT in a non-Asian patient. We also perform a review of the literature regarding IgG4-related disease and IgG4-related HT. Our case highlights this new variant of the well known HT, and helps physicians in recognizing its main clinical features, allowing for proper diagnosis and treatment.

A tireoidite de Hashimoto (TH) foi caracterizada durante muitos anos como uma entidade clinicopatológica bem definida, mas é atualmente considerada uma patologia heterogênea. A TH associada a IgG4 apresenta-se como um novo subtipo, sendo caracterizada por inflamação da tireoide com numerosos plasmócitos IgG4-positivos e fibrose extensa. É possível que pertença ao espectro da doença sistêmica associada a IgG4. Relatamos o caso de um homem português de 56 anos que se apresentou com aumento progressivo do volume cervical e disfagia, com um mês de evolução. A avaliação laboratorial revelou elevação dos parâmetros inflamatórios, hipotireoidismo subclínico e níveis muito elevados de autoanticorpos tireoidianos. Por ultrassonografia cervical demonstrou-se tireoide aumentada, heterogênea, com dois nódulos hipoecoicos. Foi realizada citologia aspirativa com agulha fina guiada por ultrassom, compatível com tireoidite linfocítica. O doente foi submetido à tireoidectomia total e o exame histológico revelou achados típicos de TH, extensa fibrose localizada dentro da cápsula tireoidiana e infiltrado linfoplasmocitário, com >50 plasmócitos IgG4-positivos por campo de grande ampliação e uma relação IgG4/IgG >40%. Após cirurgia, a concentração sérica de IgG4 encontrava-se no limite superior do normal. Ocorreu melhoria sintomática e redução dos parâmetros inflamatórios. A função tireoidiana foi controlada com levotiroxina. Relatamos o primeiro caso de TH associada a IgG4 num indivíduo não asiático. Além disso, realizamos uma revisão da literatura sobre doença associada a IgG4 e TH associada a IgG4. Este caso destaca uma nova variante da TH e permite aos médicos reconhecerem suas principais características clínicas, proporcionando diagnóstico e tratamento adequados.

Clinical immunological and pathological study of thyroid swellings in children and their management

Thyroid swellings in childhood pose an important diagnostic and therapeutic problem. The study was conducted to determine the different causes of thyroid swellings in children in Alexandria and their management; and to evaluate the different noninvasive diagnostic tools. Thirty three patients [22 girls and 11 boys][mean age 10.5 +/- 3.6 years] presenting with thyroid swellings and 13 healthy children [8 girls and 5 boys] were included in the study. Serum total triiodothyronine [RIA], total thyroxine [RIA], thyroid stimulating hormone [RIA], and antithyroid peroxidase [TPO] antibodies [ELISA] were measured in all subjects. The thyroid gland was scanned using real time high resolution ultrasonography. Histopathologic examination was performed in 17 cases treated surgically. Fifteen patients [45.5%] had diffuse goitre while solitary and multiple nodules were present in 30.3% and 24.2% of the patients, respectively. Chronic lymphocytic thyroiditis [CLT] constituted the most common cause of goitre [36.4%], followed by: Graves' disease [12.1%], simple colloid goitre [12.1%], dyshormonogenesis [9.1%], follicular adenoma [9.1%], simple multinodular goitre [9.1%], papillary carcinoma [6.1%], simple cyst [3%], benign teratoma [3%], and amyloidosis [3%]. Serum antiTPO antibodies were positive in 83.3% and 75% of patients with CLT and Graves' disease, respectively, but negative in all other conditions. Ultrasonography gave an accurate differentiation between nodular [solitary or multiple] and diffuse disease. All subjects with hyperthyroid goitre were due to Graves' disease. CLT and dyshormonogenesis were responsible for the hypothyroid goitre. Sixty percent of solitary thyroid nodules were due to focal CLT and follicular adenoma. Papillary carcinoma represented 20% of these nodules. Appropriate surgery was performed mainly in nodular goiter