The creation of the international thymic malignancies interest group as a model for rare diseases

Juan Rosai as master of our comprehensive understanding of thymus and thymoma

In this study, the authors report on the activity of Juan Rosai, one of the pathologists most engaged in the definition of cells, diseases and tumors occurring in the thymus and in the mediastinum during the last 60 years. With his morphological skills and tireless interest in clarification of disease patterns, he contributed extraordinarily to expand our knowledge of the mediastinal diseases and to improve our diagnostic approach. He determined extraordinary advances also in trasmission electron microscopy and in immunohistochemistry as powerful diagnostic tools. Moreover, he proposed and promoted, together with an international panel of Pathologists, the World Health Classification of Thymic tumors as a definite progress in our comprehension and diagnostics of thymic epithelial tumors (TET). Our purpose is to review J. Rosai's achievements in thymic normal structure, in TET and particularly in the entity now definied as "thymoma", in distinction from the thymic carcinoma. To do this, our narrative will also be based on personal memories, longstanding collaborations and/or friendship with J. Rosai.

Thymic Epithelial Tumors as a Model of Networking: Development of a Synergistic Strategy for Clinical and Translational Research Purposes

Among the group of thymic epithelial tumors (TET), thymomas often show either uncertain or explicit malignant biological behavior, local invasiveness, and intrathoracic relapse and are often difficult to manage. From the initial stages, thymic carcinomas tend to show aggressive behavior and extrathoracic spread. Moreover, the interplay of epithelial cells and thymocytes in thymomas causes complex immune derangement and related systemic autoimmune diseases. Due to their rare occurrence and to the limited funding opportunities available for rare tumors, it is challenging to make advances in clinical and translational research in TET. The authors of this paper are all members of a multidisciplinary clinical and research thoracic tumor team. Strong input was given to the team by long-standing expertise in TET in the Pathology Department. In addition, thanks to the collaboration between research units at our Institute as well as to national collaborations, over the last 10 years we were able to perform several tissue-based research studies. The most recent studies focused on microRNA and on functional studies on the thymic carcinoma cell line 1889c. The recent implementation of our biobank now provides us with a new tool for networking collaborative research activities. Moreover, the participation in a worldwide community such as ITMIG (International Thymic Malignancy Interest Group) has allowed us to significantly contribute toward fundamental projects/research both in tissue-based studies (The Cancer Genome Atlas) and in clinical studies (TNM staging of TET). Our achievements derive from constant commitment and long-standing experience in diagnosis and research in TET. New perspectives opened up due to the establishment of national [the Italian Collaborative Group for ThYmic MalignanciEs (TYME)] and European reference networks such as EURACAN, for an empowered joint clinical action in adult solid rare tumors. The challenge we face still lies in the advancement of clinical and basic science in thymic epithelial malignancies.

Thymic Carcinoma Management Patterns among International Thymic Malignancy Interest Group (ITMIG) Physicians with Consensus from the Thymic Carcinoma Working Group

INTRODUCTION

Thymic carcinomas are rare epithelial malignancies with limited data to guide management.

METHODS

To identify areas of agreement and variability in current clinical practice, a 16-question electronic survey was given to members of the International Thymic Malignancy Interest Group (ITMIG). Areas of controversy were discussed with the Thymic Carcinoma Working Group and consensus was achieved, as described.

RESULTS

A total of 100 ITMIG members responded. There was general agreement regarding the role for multimodality therapy with definitive surgical resection in physically fit patients with advanced but resectable disease. Areas of controversy included the need for histologic confirmation before surgery, the role of adjuvant therapy, the optimal first-line chemotherapy regimen, and the recommended treatment course for marginally resectable disease with invasion into the great vessels, pericardium, and lungs.

CONCLUSIONS

The results of the questionnaire provide a description of the management of thymic carcinoma by 100 ITMIG members with a specific interest or expertise in thymic malignancies. Although there was agreement in some areas, clinical practice appears to vary significantly. There is a great need for collaborative research to identify optimal evaluation and treatment strategies. Given the need for multimodality therapy in many cases, a multidisciplinary discussion of the management of patients with thymic carcinoma is critical.