IgG4-related disease with possible myocardial involvement. / Enfermedad relacionada con IgG4 con posible afectación miocárdica.

IgG4-related disease is characterized by mass lesions, a dense lymphoplasmacytic infiltrate with immunohistochemical positivity for IgG4, storiform fibrosis and, frequently, elevated serum IgG4 levels. It can be multisystemic; however, myocardial involvement, which is objectively determined by imaging tests, has not been described in the medical literature. We report the case of a man with IgG4-related disease with possible myocardial involvement, detected by cardiac magnetic resonance. This raises the question of a differential diagnosis with other diseases such as sarcoidosis and Fabry disease, the differential diagnosis of which is of great importance due to its therapeutic impact.

IgG4-related disease in thymus. A very rare case of chronic fibrosis mimicking sarcoidosis.

IgG4-related disease (IgG4-RD) is a multi-organ immune-mediated chronic fibroinflammatory condition, with unclear certain etiology. It is morphologically characterized by storiform fibrosis, dense IgG4-positive lymphoplasmacytic infiltrate, and obliterative phlebitis. It was recognized as a systemic condition as recently as 2003. IgG4-RD has been described in virtually every organ, forming sclerosing masses, and often mimicking tumors. Clinically, patients present unspecific symptoms and this condition is often recognized incidentally. The epidemiology remains poorly studied, but it has been noted that in the majority of recorded instances, patients are middle-aged men. IgG4-RD could mimic conditions other than tumors, such as infection, inflammation, or other systemic disorders. To ensure accuracy of diagnosis, an exhaustive histopathological analysis is required, together with clinical, radiological, and serological data. Thymic fibrosis in the absence of other primary thymic lesions is a very rare occurrence; in English literature only 1 case has been reported with scattered IgG4 plasma cells infiltrate and focal obliterative phlebitis. We will describe, for the first time, the case of a 49-year-old man displaying an anterior mediastinic, hilar, and intramyocardial mass simulating a sarcoidosis, with a definitive diagnosis of IgG4-related thymic fibrosis extending to the mediastinum and the heart. At the histological examination, we found many features of IgG4-RD in the thymic tissue, such as diffused storiform fibrosis, dense lymphoplasmacytic infiltrate with abundant plasma cells IgG4 positive (ratio IgG/IgG4: 40%), obliterative phlebitis, eosinophilic infiltrate, and Castleman-like lymphoid follicles. We discussed the differential diagnosis and reviewed the literature and the other cases of IgG4-related diseases that had been diagnosed in our department.

Enfermedad relacionada con IgG4 con posible afectación miocárdica / IgG4-related disease with possible myocardial involvement

La enfermedad relacionada con el depósito de IgG4 es una entidad caracterizada por lesiones tumefactas, infiltrado denso linfoplasmocítico con positividad inmunohistoquímica para IgG4, fibrosis estoriforme y, frecuentemente, niveles séricos elevados de IgG4. Puede cursar con afectación multisistémica; sin embargo, la afectación miocárdica, objetivada mediante pruebas de imagen, no ha sido descrita en la literatura médica. Se presenta el caso clínico de un varón afecto de enfermedad relacionada con IgG4 con posible afectación miocárdica, detectada a través de cardiorresonancia magnética, que plantea el diagnóstico diferencial con otras enfermedades como la sarcoidosis y la enfermedad de Fabry, cuyo diagnóstico diferencial es de gran importancia por su repercusión terapéutica

IgG4-related disease is characterized by mass lesions, a dense lymphoplasmacytic infiltrate with immunohistochemical positivity for IgG4, storiform fibrosis and, frequently, elevated serum IgG4 levels. It can be multisystemic; however, myocardial involvement, which is objectively determined by imaging tests, has not been described in the medical literature. We report the case of a man with IgG4-related disease with possible myocardial involvement, detected by cardiac magnetic resonance. This raises the question of a differential diagnosis with other diseases such as sarcoidosis and Fabry disease, the differential diagnosis of which is of great importance due to its therapeutic impact