A Developing Anterior Mediastinal Mass In A Breast Cancer Patient : Thymic Hyperplasia

Introduction: True thymic hyperplasia following chemotherapy have been described mostly in children.There are a few cases of thymus hyperplasia have been reported in breast cancer patients . Diagnosis of this unusual entity is very crucial to pretend unnecessary surgery or interventional diagnostic procedures. Case Presentation: We report a case of thymus hyperplasia in a patient who was operated and treated with adjuvant chemotherapy for stage 2 breast cancer two years ago. In the follow-up CT scans an anterior mediastinal mass was noted. Radiologic evaluation and follow up revealed thymus enlargement. Discussion: Thymic hyperplasia following chemotherapy have been described in both children and adults, but occurs mostly in children and adolescents treated for lymphoma and several other types of tumors. Few cases are reported in literature describing thymus hyperplasia following chemotherapy in a breast cancer patient. Conclusion: Radiologists must be aware of this unusual finding in breast cancer patients treated with chemotherapy to guide the clinicians appropriately in order to avoid unnecessary surgical intervention, additional invasive diagnostic procedures, or chemotherapy.

Polymorphism of clinical phenotypes and heterogeneity of autoimmune targets of myasthenia gravis

The aim of the study was to evaluate the presence of autoantibodies to different subunits of nAChR and nuclear antigens at different myasthenia phenotypes. The work has investigated the presence of antibodies to α1- and α7-subunits of nAChR, the repertoire and frequency of occurrence of antinuclear autoantibodies in different clinical phenotypes of myasthenia to understand the mechanisms of pathogenesis of various forms of the disease. Additional factors of autoimmunization were identified that affect certain mechanisms of pathogenesis in thymus-independent and thymus-dependent myasthenia gravis. Autoantibodies to α1 and α7 subunits of nAChR were detected in case of thymus-independent myasthenia gravis and thymus-dependent myasthenia gravis with thymus hyperplasia or locally spread thymoma, as well as the presence of antinuclear antibodies in case of thymoma on the background of myasthenia gravis. Autoantibodies to the α1 subunit of nAChR are available in all patients with thymus-independent and thymus-dependent myasthenia gravis; the maximum titer was in patients with myasthenia and thymus hyperplasia. The presence of autoimmune antibodies to another target – to the α7 subunit of nAChR was found in patients with thymus-independent myasthenia gravis and with myasthenia and thymus hyperplasia. Detected anti-nuclear antibodies (ANA) in patients with thymoma, are preferably antibodies to structures that are directly involved in mitotic cell division, that is to centromere, to centromeric protein F, to the centrosomal protein of achromatin spindle – NuMa and MSA-2 antigen mitotic spindle that affects the course of cell proliferation, reparative and regenerative processes in tissues. The selectivity of antibody damage by the subunit of NAHR in different myasthenia phenotypes and the presence of ANA in thymus-dependent myasthenia with thymoma has great diagnostic and prognostic value. The presence of specific autoantibodies to certain nuclear structures of the cell, along with other autoimmunization mechanisms, affects various metabolic mechanisms and can be used to select targeted therapy taking into account individual pathogenic targets of the autoimmune process.

Features of self-tolerance loss in patients with different clinical phenotypes of myasthenia

The incidence of myasthenia gravis which is characterized by progressive muscular weakness on the background of structural disorders of the thymus, has increased. Myasthenia gravis is a multifactorial autoimmune disease, it has a pronounced clinical heterogeneity, and therefore the standard diagnostic and treatment protocol is not always effective. To substantiate an individual approach to the treatment of various clinical forms of myasthenia, we conducted a study of mechanisms and markers of loss of central and peripheral self-tolerance in thymus-independent myasthenia (M) and thymus-dependent myasthenia gravis with thymus hyperplasia (MH) and thymoma (MT), involving a total of 427 patients examined. In patients with different phenotypes of myasthenia, we used the methods of spectrophotometry, flow cytometry, enzyme immunoassay. In patients with MH on the background of lymphofollicular thymus hyperplasia we revealed a pronounced humoral sensitization in comparison with the reference values: the concentration of C4 complement, C-reactive protein, circulating immune complexes and the initiation of an indirect autoimmune reaction a reliable increase in autoantibodies (AAbs) to the α1 and α7 subunit of subunit of nicotinic receptors (nAChR). In M and MT groups a high similar titer of AAbs to other epitopes was revealed: DNA, β2-glycoprotein I, membranes of intestinal and stomach cells, lung, liver, kidney cells. A pronounced blast-transforming response to the presence of the mitogen PHA was revealed in the MT group. In the MT group, a decrease in the content of CD4+ CD28+ co-stimulatory molecules and in the MH group, a decrease in СD4+ CD25+ Treg lymphocytes was revealed. Individual methods for correcting the loss of self-tolerance in patients with different clinical phenotypes of myasthenia were justified taking into account the use of immunosuppression, specific viral-neutralizing immunoglobulins and massive IgG immunoglobulin therapy, and the application of anti-inflammatory recombinant interleukins.

Impact of Different Thymic Pathologies on the Clinical Course of Myasthenia Gravis: A Population Wide Study in Latvia / Aizkrūts Dziedzera Patoloģiju Ietekmeu uz Myasthenia Gravis Klīnisko Gaitu: Populācijas Pētījums Latvijā

Myasthenia gravis (MG) is an autoimmune disease characterized by autoantibody mediated postsynaptic failure of neuromuscular transmission. The thymus gland has a role in the pathogenesis of MG. The aim of this study was to determine (1) the prevalence of different thymic pathologies in the MG patient population of Latvia; (2) the potential impact of different thymus pathologies on the clinical course of MG; and (3) the effectiveness of surgical treatment of thymic pathologies in Latvia. The results showed that the most common thymus pathology among the patients with MG in Latvia is thymoma. Compared to the published data, the proportion of MG patients diagnosed with thymus hyperplasia in Latvia is very small. Thymus hyperplasia is uncommon among patients 60 years of age and older. MG onset for patients with thymoma is significantly later than that of patients with thymus hyperplasia. Almost all patients with thymoma or thymus hyperplasia develop a generalised form of MG. The presence of a thymus pathology does not significantly affect the electrophysiological test results, clinical symptom severity, frequency of disability or hospitalisation of the patients with MG. Thymectomy in patients with thymoma or thymus hyperplasia has no significant effect on relieving MG symptoms