A case of post-thymomectomy myasthenia gravis after extrapleural pneumonectomy for invasive thymoma which necessistated long-term mechanical ventilation]

The patient was a 58-year-old male with invasive thymoma which had disseminated in the left thorax and was histologically a polygonal cell type lesion. While the serum value of anti-acetylcholine receptor antibody was high before surgery, there were signs of myasthenia gravis. After preoperative chemotherapy, a thymectomy and left panpleuropneumonectomy were conducted. Forty days after surgery, the patients suffered post-thymomectomy myasthenia gravis, which necessitated mechanical ventilation for 6 months. Despite steroid therapy and 17 plasmapheresis procedures the tidal volume increased by little more than 200-250 ml during that time. The causes of ventilatory failure, therefore, were probably decreased pulmonary function due to extrapleural pneumonectomy and the myasthenia gravis. According to the literature, polygonal cell type thymomas with high serum levels of anti-acethycholine receptor antibody have higher incidences of post-thymomectomy myasthenia gragvis than other ones. Therefore, the risk of post-thymomectomy myasthenia gravis should be kept in mind when extrapleural pneumonectomy for invasive thymoma is being considered, especially in the cases of this type.     

Thymomes et maladies auto-immunes

The association between thymoma and autoimmunity is well known. Besides myasthenia gravis, which is found in 15 to 20% of patients with thymoma, other autoimmune diseases have been reported: erythroblastopenia, systemic lupus erythematosus, inflammatory myopathies, thyroid disorders, Isaac's syndrome or Good's syndrome. More anecdotally, Morvan's syndrome, limbic encephalitis, other autoimmune cytopenias, autoimmune hepatitis, and bullous skin diseases (pemphigus, lichen) have been reported. Autoimmune diseases occur most often before thymectomy, but they can be discovered at the time of surgery or later. Two situations require the systematic investigation of a thymoma: the occurrence of myasthenia gravis or autoimmune erythroblastopenia. Nevertheless, the late onset of systemic lupus erythematosus or the association of several autoimmune manifestations should lead to look for a thymoma. Neither the characteristics of the patients nor the pathological data can predict the occurrence of an autoimmune disease after thymectomy. Thus, thymectomy usefulness in the course of the autoimmune disease, except myasthenia gravis, has not been demonstrated. This seems to indicate the preponderant role of self-reactive T lymphocytes distributed in the peripheral immune system prior to surgery. Given the high infectious morbidity in patients with thymoma, immunoglobulin replacement therapy should be considered in patients with hypogammaglobulinemia who receive immunosuppressive therapy, even in the absence of prior infection.     

Experience with surgery for thymoma associated with pure red blood cell aplasia. Report of three cases

We present three cases of thymoma associated with pure red blood cell aplasia in which thymomectomy and thymectomy were performed. Case 1, a patient with pure red blood cell aplasia and hypogammaglobulinemia, was treated after surgery with immunosuppressive agents. She did not show any remission and died eight months after the operation. Case 2, a patient with pure red blood cell aplasia alone, showed transient erythropoiesis only in the early post-operative period and died one year and seven months after the operation. Patient 3 had pure red blood cell aplasia alone before surgery and was treated after surgery with prednisolone and fluoxymesterone. He showed good remission from the aplasia after these treatments; however, myasthenia gravis appeared seven months after the operation. These results seem to show that such combined therapy as applied in case 3 may be effective for some of the patients with pure red blood cell aplasia and thymoma; however, the effects of thymomectomy or thymectomy (or both) are still controversial for the treatment of pure red blood cell aplasia.     

Early and late results after thymectomy in myasthenia gravis: a retrospective study [correction of analysis]

BACKGROUND: This study aims to evaluate the early and late outcome of patients treated by surgery for myasthenia gravis and the diagnostic value of the Besinger Score, which is based on a correlation of severity of symptoms with specific antibodies to acetylcholine receptors, in the follow-up investigation after surgical therapy. METHODS: Between June 1984 and April 1992 thoracotomy was performed in 51 myasthenia gravis cases at our department. The retrospective analysis considered patients with (n = 13) or without thymoma (n = 38). The Besinger score was used to describe the severity of disease preoperatively and up to 5 years postoperatively. RESULTS: The Besinger score fell continually post surgery. Changes in relative serum concentrations of antibodies were similar to the Besinger score. Five years after thymectomy complete remission was diagnosed in 40% of the patients. The required dosage of pyridostigmine had fallen by two thirds after 5 years. Patients with follicular hyperplasia had significantly higher remission rates than those with thymoma. CONCLUSIONS: Surgery for myasthenia gravis is successful. The Besinger score well quantifies the severity of the disease.     

Thymoma associated with pure red-cell aplasia: clinical features and prognosis

As information on the clinical features and prognosis of thymoma complicated by pure red-cell aplasia is limited, follow-up data on thymoma patients who had a thymectomy between 1954 and 1999 were analyzed retrospectively. Six of 166 cases were complicated by pure red-cell aplasia. In 3 of these, the pure red-cell aplasia appeared after surgical intervention. Remission was observed in 2 patients who underwent extended thymectomy. The other 4 patients subsequently died from pure red-cell aplasia. The outcome in patients with pure red-cell aplasia was poorer than that in the entire group of patients with thymoma and in those with thymoma complicated by myasthenia gravis. The possible onset of pure red-cell aplasia after thymectomy should be kept in mind during follow-up.     

Discordant thymectomy in identical twins concordant for myasthenia gravis

BACKGROUND: Thymectomy is standard therapy fornonthymomatousmyasthenia gravis despite the absence of randomized clinical trials (1). Myasthenia gravis is uncommonly reported in monozygous twins; disease concordance occurs in approximately one third of such identical twin pairs; and treatment for myasthenia gravis, when described,is usually concordant in identical twin pairs (2).OBJECTIVE: To report an 11-year clinical course of a pair of identical twins concordant for generalized acetylcholine receptor antibody–positive nonthymomatous myasthenia gravis in whom only 1 was treated with extended transsternal thymectomy. CASE REPORT: Twin A was a 19-year-old white woman who presented with an 8-week history of intermittent leg weakness, causing her to fall during activities, such as climbing stairs. On examination,she had moderately severe fatigable proximal muscle weakness and ptosis. Her weakness improved with intravenous edrophonium administration.Initial binding acetylcholine receptor antibody titer was 1.22 nmol/L (normal value, 0.03 nmol/L). Repetitive 2-Hz nerve(median, ulnar, and facial) stimulation studies demonstrated up to a 16% decremental response. Chest computed tomography showed residual thymic tissue without thymoma. An extended transsternal thymectomy was performed 11 weeks after the onset of symptoms.     

Malignant thymoma associated with myasthenia gravis, Graves' disease, and SIADH

Patients with thymoma are likely to present with associated autoimmunologic disorders. The occurrence of syndrome of inappropriate antidiuretic hormone (SIADH) attributable to thymoma is extremely rare. We herein present an extremely rare case of a 59-year-old man patient who was discovered to have malignant thymoma associated with myasthenia gravis, Graves' disease, and SIADH. He was admitted for evaluation and treatment of hyponatremia (Na 125 mEq/l). SIADH was diagnosed, and thymoma was identified as its cause. The patient was also found to have both Graves' disease and myasthenia gravis. The hyponatremia was normalized with water restriction and 3% saline therapy before thymectomy. The thymic tumor was a Masaoka stage III thymoma that resulted in direct invasion to the wall of the innominate vein, but there was no finding of invasion to other mediastinal organs. Complete thymectomy with innominate vein graft was performed. Microscopic histopathology findings corresponded to those of a mixed-type thymoma and type B2. However, immunohistochemical stain for antidiuretic hormone was negative in the tumor cells. Adjuvant radiation therapy was employed postoperatively, and the patient's postoperative recovery was uneventful. He subsequently reached a euthyroid state. And the reversal to normal sodium and osmolality levels was continued after the tumor removal without any further management for hyponatremia. The observation of this interesting case and a literature review provided us with the opportunity to explore the pathogenesis and clinical aspects of thymoma-related autoimmune and/or endocrine disorders which must be suspected in patients with thymoma.     

Postoperative respiratory care after transsternal thymectomy in myasthenia gravis. A 3-year experience in 53 patients

During a three-year period, 53 patients with myasthenia gravis underwent transsternal thymectomy by a partial sternum-splitting technique at our institution. This procedure was carried out (1) because an x-ray film or a computed tomography scan had suggested the presence of a thymoma or (2) to manage symptoms of myasthenia gravis. In 41 patients the endotracheal tube was removed in the post-anesthesia recovery room. The remaining 12 patients were extubated in the Respiratory Care Unit--in five, after prolonged mechanical ventilation. From our experience, the only factor useful for predicting the probable need for prolonged postoperative mechanical ventilation is the degree of bulbar involvement. Patients in Osserman classification groups 3 and 4 have an extremely high incidence of postoperative respiratory failure. Consideration should be given to the use of preoperative plasmapheresis in myasthenia gravis patients who have significant bulbar symptoms.     

胸腺瘤伴重症肌无力患者瘤组织中Bcl-2和Fas的表达水平

目的 探讨凋亡相关基因bcl-2、Fas在胸腺瘤伴重症肌无力患者瘤组织中的表达状况及其临床意义。方法经手术治疗的25例胸腺瘤伴重症肌无力患者的肿瘤组织标本为病例组，25例先天性心脏病患者手术时切取的正常胸腺组织标本为对照组，通过免疫组化的方法检测两组标本中Bcl-2和Fas蛋白的表达水平。结果胸腺瘤中Bcl-2及Fas表达水平均显著高于对照组，经Ridit分析两者差异均有统计学意义（U值分别为2．645、3．200，P均〈0．05），但Bcl-2和Fas的表达水平与胸腺瘤患者的重症肌无力Ossermen分型、术前病程、年龄及性别等临床因素均无显著相关。结论 Bcl-2和Fas在胸腺瘤伴重症肌无力的发病中可能具有重要作用。     

Thymoma with pemphigus foliaceus

A 75-year-old Japanese woman was referred to us because of an anterior mediastinal mass. Crusts and shallow erosions developed 10 months earlier on her upper chest, back, and scalp. Pemphigus foliaceus was diagnosed based on histological examination of skin biopsy specimens and positivity for serum anti-desmoglein 1 antibody by enzyme-linked immunosorbent assay. Neurological examination and electromyography ruled out myasthenia gravis. Total thymectomy was performed, and the postoperative pathology studies showed mixed lymphoepithelial thymoma. One year after the resection, the eruption and alopecia improved and the serum anti-desmoglein 1 antibody titer decreased, suggesting a beneficial effect of thymectomy on thymoma-related pemphigus.     

THE THYMUS: EXPERIMENTAL PHYSIOLOGY,AND PATHOLOGY IN MAN

The thymus is an integral part of the immunological system. It is a site of intense lymphopoiesis, especially in early life. Neonatal thymectomy in mice causes runting and death due to gross immunological deficiencies. These deficiencies are determined by lymphopenia, and by lack of a lymphotrophic hormone secreted by the epithelial cells of the medulla; this hormone confers on lymphocytes the capacity to respond to antigenic stimulation. The thymus may be the main source of lymphoid cells carrying new or primary patterns of immune reactivity; it is thus “first-level” or “central” lymphoid tissue, which seeds cells to “second-level” or “peripheral” lymphoid tissues in the lymph nodes and spleen. Pathological lesions of the thymus in man include aplasia, hyperplasia, dysplasia and neoplasia. Gross aplasia characterizes the immunological deficiency diseases of infancy, including the lymphopenic type of congenital agammaglobulinæmia. Hyperplasia accompanies thyrotoxicosis. Dysplasia refers to the lymph follicle-germinal centre development in myasthenia gravis, probably an autoimmune disease, and to the proliferation in the medulla of spindle-epithelial cells in lupus erythematosus, an autoimmune disease. Neoplasia occurs as benign thymoma, which may be accompanied by extrathymic diseases which are possibly autoimmune in origin; these include myasthenia gravis, red cell aplasia, polymyositis, agammaglobulinæmia and lupus erythematosus. These diseases may in some way be caused by the thymoma; alternatively, the thymoma may represent the result of continuing hyperplasia of the thymus provoked by a primary autoimmune process. The place of thymectomy in the treatment of autoimmune disease is discussed. It is an established procedure in myasthenia gravis, and has been successful in two cases of autoimmune hæmolytic anæmia in infancy. We review our experience with thymectomy for three patients with systemic lupus erythematosus.     

Pancreatic Cancer in a Patient with Myasthenia Gravis

Myasthenia gravis has been associated with several diseasessuch as hyperthyroidism and malignancy (thymoma,lung carcinoma) but so far no reports have demonstrated arelationship between this disease and pancreatic disease.We report a 66-year-old man with myasthenia gravis diagnosedon the basis of clinical symptoms (eyelid ptosis),typical abnormalities on repetitive nerve-stimulation tests,and the presence of Ach-R antibodies in the serum. The responseto anticholinesterasic agents (pyridostigmine) wasgood, but after 1 year, he developed pancreatic cancer andmyasthenia gravis symptoms recurred. After surgery andchemotherapy, myasthenia gravis symptoms disappeared.Some months later, the patient had a recurrence of pancreaticcancer after relapse of myasthenia gravis.     

Malignant thymoma complicated by amegakaryocytic thrombocytopenic purpura

We report the case of a 41-year-old man with malignant thymoma complicated by amegakaryocytic thrombocytopenia 10 years after diagnosis of myasthenia gravis. A bone marrow aspirate showed an absence of megakaryocytes with normal maturation and differentiation of myeloid precursors. Three months later, severe neutropenia occurred, and a bone marrow examination confirmed the diagnosis of severe aplastic anemia. Associations between thymoma and myasthenia gravis, between thymoma and pure red cell aplasia, and between thymoma and aplastic anemia are well documented. Amegakaryocytic thrombocytopenia is not a recognized paraneoplastic syndrome complicating thymoma. Amegakaryocytic thrombocytopenia complicating thymoma may be a very early presentation of impending aplastic anemia.     

Myasthenia gravis and hyperthyroidism: two cases

It is well known that hyperthyroidism occurs in approximately 2 to 17.5% of patients with myasthenia gravis. Hyperthyroidism may influence the clinical course of myasthenia gravis. We report the cases of two patients, a 53-year-old man and an 18-year-old woman, who had both severe myasthenia gravis and hyperthyroidism due to Graves' disease. Myasthenia gravis affected in particular facio-ocular areas with diffuse myopathy and signs of neuromuscular block on the electromyogram. In one patient, the diagnosis of thyroid disease was made three months before the diagnosis of myasthenia gravis while in the other, thyroid disease was recognized four months after myasthenia gravis. Myasthenia gravis worsened after the development of hyperthyroidism in the second patient. Both patients were given anti-cholinesterase drugs. One underwent thymectomy. Radioiodine used for the treatment of hyperthyroidism improved the symptoms of myasthenia gravis in the first patient. The association of myasthenia gravis and hyperthyroidism is more than a coincidence; our cases illustrate the difficult diagnosis and management of these diseases. Clinicians should look for myasthenia gravis in hyperthyroid patients and vice versa, especially when symptoms of myasthenia gravis or hyperthyroidism worsen.     

Thymectomy for myasthenia gravis: 12-year experience

Thymectomy has been shown to be effective in the treatment of myasthenia gravis. The logical goal of operation is the complete removal of the thymus, but there is no consensus on the selection criteria of patients for surgery and the choice of surgical approach. We retrospectively reviewed 56 patients with myasthenia gravis who had been treated surgically by transsternal radical thymectomy between January 1990 and March 2002. The patients were symptomatically grouped according to the modified Osserman clinical classification. There was 1 hospital death, and 53 patients had been followed up for between 1 month and 12 years. Improvement after thymectomy was observed in 1 of 4 patients (25%) in Osserman group I, 25 of 34 patients (74%) in Osserman group IIA, and 16 of 18 patients (89%) in combined Osserman groups IIB and IIC. Transsternal radical thymectomy is an effective therapy for myasthenia gravis. Sustained improvement is achievable in female patients with moderate to severe symptoms and in patients with thymic hyperplasia.     

Pseudoischemic Electrocardiogram in Myasthenia Gravis with Thymoma: Reversibility After Thymectomy

Abnormal ST T‐wave changes can be found at presentation in various noncoronary disorders; misinterpretation of these patterns as ischemic heart disease can lead to erroneous diagnosis and treatment. Here we present a case of myasthenia gravis (MG) with thymoma, in which the resting electrocardiogram (ECG) led to a misleading diagnosis of myocardial ischemia. After thymectomy, the ECG resumed a normal pattern. Myasthenia gravis is not usually considered in the differential diagnosis of conditions associated with an abnormal ECG. The combination of dysphagia, dyspnoea, ECG changes, and creatine kinase (CK) elevations may easily bring to mind an erroneous and possibly deleterious diagnosis of myocardial ischemia. Copyright © 2009 Wiley Periodicals, Inc.     

Pleural dissemination of thymoma showing tumor regression after combined corticosteroid and tacrolimus therapy

We present the case of an elderly woman with myasthenia gravis who had pleural dissemination of thymoma reduced by treatments with a moderate dose of corticosteroids and a conventional dose of tacrolimus. A maintenance dose of prednisolone for myasthenia gravis could not shrink the size of the disseminated thymoma, but prednisolone (>30 mg daily) succeeded in reducing the size of the tumor. Moreover, a combination with tacrolimus enabled the daily dose of prednisolone to be tapered off without recurrence of myasthenia gravis, and the disseminated thymoma almost disappeared. A moderate or higher dosage of corticosteroids with tacrolimus may, in some cases, be an effective procedure for pleural dissemination of thymoma. Treatment should be undertaken on a trial basis for patients not indicated for surgery, radiotherapy, or chemotherapy.     

Predictors of outcome for myasthenia gravis after thymectomy

The aim of this study was to assess the clinical outcome of patients with myasthenia gravis treated with maximal thymectomy and to identify prognostic variables that predict the outcome. Over 15 years, from 1986 to 2001, we collected data on 100 patients with myasthenia gravis who underwent maximal thymectomy and retrospectively reviewed their outcome. Women comprised 63% and the median age was 25 years (range, 4 to 61). The median duration of the disease was 26 months (range, 1 to 240). According to the Osserman classification, there were seven patients in class I, 31 in class II, 47 in class III, and 15 in class IV. In non thymomatous patients (93 patients), complete remission rate progressively increased from 37.4% to 58.2% and 75% at 3, 10 and 15 years of follow-up respectively. These findings suggest that the complete remission rate is prone to increase with time after maximal thymectomy. The total benefit rate achieved was estimated to be 86% while 14% did not improve at a mean follow-up period of 7.6 years (range, 8 to 180 months). Univariate analysis (p < 0.05) showed that age, thymic histology and ectopic thymic tissue are significant prognostic factors for outcome.     

Chylothorax following extended thymectomy for myasthenia gravis

The effectiveness of extended thymectomy for the treatment of myasthenia gravis is well documented. Most of the postoperative complications have been related to respiratory distress or wound complication, but chylothorax following thymectomy has been reported as a rare complication. From January 1995 to December 2004, 217 patients underwent extended thymectomy for myasthenia gravis at Taipei Veterans General Hospital. Three cases (1.38%) developed chylothorax after operation. Injury to the unseen division of the mediastinal lymphatics and branches from the thoracic duct during extensive dissection of perithymic fat tissue, which is seldom performed in classical thymothymectomy procedures, may have been the main cause of this complication. Two of the cases received conservative treatment and recovered uneventfully. The other patient (0.46%) underwent ligation of the thoracic duct 3 months later, which also resulted in the complication being cured. Conclusions: Post-thymectomy chylothorax is rare and seems to be related to extended thymectomy. Even a small invasive procedure such as VATS for extended thymectomy formyasthenia gravis could be complicated by chylothorax. We recommend that if chylothorax develops after thymectomy, conservative treatment is the treatment of choice; however, thoracic duct ligation is a useful method for treating long-term unhealed chylothorax.     

Retrospective analyses of clinical features and therapeutic outcomes in thymectomized patients with myasthenia gravis at Shinshu University

OBJECTIVES: Thymectomy has become recognized as an integral element in the treatment of patients with myasthenia gravis (MG). Although the incidence of elderly-onset MG has recently been increasing, there is little data demonstrating the efficacy and complications of thymectomy in this population. To clarify this point, we divided the thymectomized patients with MG into young and elderly groups, and retrospectively examined their clinical features and therapeutic outcomes. PATIENTS AND METHODS: We reviewed 57 MG patients who had been admitted to our hospital between 1988 and 2002. The patients were classified into young (younger than 60) and elderly (60 or older) groups according to the age of onset, and the therapeutic outcomes of thymectomy were evaluated using myasthenic severity scales and the duration from operation to discharge. RESULTS: Myasthenic severity scales significantly improved after thymectomy in the elderly group both with (p<0.005) and without thymoma (p<0.05) compared with before. With regard to the duration from thymectomy to discharge, no significant difference could be found between the young and elderly groups, irrespective of associated thymoma. There were no serious complications during and after thymectomy in either the young or the elderly group. CONCLUSIONS: Despite various possible complications due to aging, thymectomy should be actively considered also in the treatment of elderly MG patients because it can reliably and safely improve myasthenic symptoms in combination with immunosuppressive agents, including corticosteroid.