RESUMO
Resumen La pesquisa incidental de lesiones tímicas ha aumentado. Una adecuada aproximación a esas lesiones en la tomografía computada por emisión de positrones (PET-CT) es fundamental, pues se usa como parte de la mayoría de los procedimientos de planificación oncológica. Se han seleccionado casos representativos respecto de los aspectos más importantes de las imágenes de timo en PET-CT y cómo esa técnica puede contribuir a un diagnóstico preciso o a la planificación del tratamiento. Específicamente, presentamos una descripción general de las lesiones tímicas comunes y los imitadores de enfermedad, con énfasis en los hallazgos en PET-CT, incorporando también ejemplos de resonancia magnética (RM).
Abstract Incidental thymic lesion findings have increased. An adequate characterization of these lesions in positron emission computed tomography (PET-CT) is essential, since it is used as part of most oncological planning procedures. Representative cases have been selected regarding the most important aspects of thymus imaging in PET-CT and how this technique can contribute to an accurate diagnosis or treatment planning. Specifically, we present a general description of common thymic lesions and disease mimics, with an emphasis on PET-CT findings, also incorporating examples of magnetic resonance imaging.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Adulto Jovem , Timo/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Timo/fisiologia , Timo/patologia , Hiperplasia do Timo/diagnóstico por imagem , Neoplasias do Timo/diagnóstico por imagem , Espectroscopia de Ressonância Magnética , Linfoma/diagnóstico por imagemRESUMO
Thymic hyperplasia is frequently observed in Graves' disease. However, detectable massive enlargement of the thymus is rare, and the mechanism of its formation has remained elusive. This case showed dynamic changes in thymic hyperplasia on serial computed tomography images consistent with changes in serum thyrotropin receptor (TSH-R) antibodies and thyroid hormone levels. Furthermore, the patient's thymic tissues underwent immunohistochemical staining for TSH-R, which demonstrated the presence of thymic TSH-R. The correlation between serum TSH-R antibody levels and thymic hyperplasia sizes and the presence of TSH-R in her thymus suggest that TSH-R antibodies could have a pathogenic role in thymic hyperplasia.