Coexistence of diffuse large B-cell lymphoma and papillary thyroid carcinoma in a patient affected by Hashimoto's thyroiditis

SUMMARY Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. On the contrary, primary thyroid lymphoma (PTL) is a rare disease, accounting for 2% to 5% of all thyroid malignancies. Despite several cases in which both PTC and PTL arise in the setting of Hashimoto's thyroiditis (HT), the coexistence of both tumors in HT patients is very rare. Herein we report the case of a 66-year-old woman with long-standing nodular HT under replacement therapy, who presented with a fast, painless enlargement in the right anterior side of the neck. Thyroid ultrasonography demonstrated increased growth of a hypoechoic nodule in the right lobe measuring 32 × 20 mm. A total thyroidectomy was performed, and histology revealed a diffuse large B-cell lymphoma (DLBCL) on a background of florid HT. Moreover, a unifocal papillary microcarcinoma, classical variant (7 mm, pT1aNxMx), was discovered. The patient was then treated with chemotherapy for the PTL, but she did not undergo radioactive iodine ablation treatment for the microPTC as per guidelines. Two years after surgery, the patient had no evidence of recurrence of either malignancy. This rare case highlights the importance of monitoring HT patients with nodular lesions, especially if they have long-standing disease. In addition, PTL should be considered for differential diagnosis in elder HT patients who present with sudden thyroid enlargement.

An uncommon case of Marine-Lenhart syndrome / Um caso incomum de síndrome de Marine-Lenhart

The term Marine-Lenhart syndrome describes the association between Graves’ disease and autonomously functioning thyroid nodules (AFTN), such as toxic adenoma or toxic multinodular goiter. The two diseases may coexist or may be present at different moments in the same patient. In the literature, there are many reports on the development of Graves’ disease after radioiodine treatment for AFTN, but very little information may be found on the occurrence of AFTN after radioiodine therapy for Graves’ disease. We describe here the case of a female patient with Graves’ disease who was successfully treated with radioiodine for Graves’ disease, returning to normal thyroid function. Three years later, biochemical analysis and ultrasound examination identified a thyroid nodule that progressively increased in size. The 99mTc-pertechnetate scintigraphy showed avid uptake in the right lobule, which corresponded to a nodular lesion consistent with AFTN.

O termo “síndrome de Marine-Lenhart” descreve a associação da doença de Graves e nódulos tireoidianos de funcionamento autônomo (AFTN), como no adenoma tóxico ou bócio multinodular tóxico. As duas doenças podem coexistir ou podem estar presentes em diferentes momentos no mesmo paciente. Na literatura, existem muitos relatos sobre o desenvolvimento da doença de Graves após radioiodoterapia para AFTN, mas muito poucos dados podem ser encontrados em relação ao aparecimento de AFTN após radioiodoterapia para doença de Graves. Descrevemos o caso de uma paciente do sexo feminino com doença de Graves que realizou com sucesso o tratamento com iodo radioativo, com a normalização da função da tireoide. Três anos depois, uma análise bioquímica e um exame de ultrassonografia identificaram o aparecimento de um nódulo na tireoide que progressivamente aumentou de tamanho. A cintilografia com 99mTc-pertecnetato revelou uma captação ávida no lóbulo direito, correspondente à lesão nodular, consistente com uma AFTN.