Thymic tumours associated with Myasthenia gravis: a long term observation study of operated patients

Abstract

Primary tumours of thymus, thymoma and thymic carcinoma, are very rare, they represent less than 1 % of all neoplasms. The most common manifestation of thymoma with appearance of 40 to 50 % of the neuromuscular autoimmune disease is myasthenia gravis (MG). The performance of a complete resection is the most predictive indicator for long-term survival of patients with thymic tumour, also important prognostic factors are the histological type of thymic tumour and its invasiveness. The aim of our study is to study the long-term survival of patients after the resection of the tumour, as well as enhanced effi ciency of radical thymectomy in the complex treatment of myasthenia gravis. From 1989 to 2010 we operated on 369 patients with MG. Out of 49 patients (13.7 %) 38 cases (76.6 %) were thymomas and 11 cases (23.4 %) thymic carcinomas. Complete removal of tumours (stage I, II, and III) were performed in 45 (92 %) cases. Of the 41 living patients (83.7 %), three (7.3 %) were diagnosed with metastatic thymic carcinoma or thymoma, and treated with adjuvant therapy. In one case, the patient died due to generalization of the thymic carcinoma. Statistical analysis with KaplanMeier method showed better overall survival of patients with thymoma than patients with thymic carcinoma. The difference in survival curves was not signifi cant. (Mantel-Cox p = 0.479, Generalized Wilcoxon p = 0.326). In terms of treatment of Myasthenia gravis associated with thymoma, we achieved 70 % successful clinical and pharmacological remission. On the other hand, paraneoplastic MGAT has the worst prognosis of all the other forms of MG. The difference between MGAT to every other form of MG was statistically signifi cant (Tab. 6, Fig. 1 Thymomas with thymic carcinomas present primary tumours of thymus having indolent course and sporadic occurrence. Generally, they account for less than 1 % of all oncological neoplasms but comprise 20-25 % of all mediastinal tumours (1). A larger body of literature now provides further insight into biological behaviour of thymoma playing a role in the pathogenesis of myasthenia gravis (MG). Therefore, myasthenia gravis associated with thymomas (MGAT), is also called paraneoplastic, which is an organspecifi c autoimmune disorder characterised by wavering muscular weakness and abnormal fatigue. In imunopathogenesis of MGAT participate thymic and extrathymic mechanisms. Henceforth, radical surgical removal of thymoma does not always lead to clinical improvement of MG and decreasing titre of autoantibodies that block acetylcholine receptors (AChR) (2).Thymomas are characterised by their variability of morphological appearance and are often associated with various autoimmune diseases. Previous studies report the correlation between their morphological appearance and clinical behaviour. Based on the facts, the last histological classifi cation was presented by the WHO in 1999 which was slightly modifi ed in 2004 showing a relation to clinical behaviour, tumour staging system, the prognosis and the association ...

The comparison of modified minimally invasive and open surgical approaches in the treatment of epithelial thymic tumours

“…Nevertheless, when compared to other solid malignancies, they remain favourable (8)(9)(10)(11). These attributes predestine patients with thymomas to be perfect candidates for primary surgical treatment and because of different concurrent paraneoplastic conditions such as myasthenia gravis (MG), these patients should be treated in a multidisciplinary fashion and in high-volume centres (12)(13)(14)(15). Myasthenia gravis symptoms are present in 40-45 % of patients with thymoma.…”