Abstract
AB001. Subclinical myasthenia gravis in thymomas
Florit Marcuse1,2, Monique Hochstenbag1, Janneke G. J. Hoeijmakers2,3, Myrurgia Abdul Hamid4, Jan Damoiseaux5, Jos Maessen6, Marc De Baets2
1Department of Pulmonology, Maastricht University Medical Center+, Maastricht, The Netherlands;
2School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands;
3Department of Neurology, Maastricht University Medical Center+, Maastricht, The Netherlands;
4Department of Pathology, Maastricht University Medical Center+, Maastricht, The Netherlands;
5Central Diagnostic Laboratory, Maastricht University Medical Center+, Maastricht, The Netherlands;
6Department of Cardiothoracic Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands
Correspondence to: Florit Marcuse. Department of Pulmonology, Maastricht University Medical Center+, Limburg, Maastricht, The Netherlands. Email: florit.marcuse@mumc.nl.
Background: A proportion of thymoma-patients without a history of myasthenia gravis (MG) before thymectomy, appears to have positive anti-AChR-antibodies in the serum. These subclinical MG-patients could be underdiagnosed because analyzation of anti-AChR-antibodies in thymomas is not always performed in patients who did not experience neurological symptoms. The prevalence and long-term outcomes of subclinical MG are never described in literature yet.
Methods: We retrospectively analyzed 398 consecutive patients who underwent a robotic-assisted thoracoscopic surgery at the Maastricht University Medical Center+ (MUMC+) between April 2004 and December 2018. In the MUMC+, a robotic approach is the standard surgical approach in patients with thymic diseases. Inclusion criteria were thymomas, thymectomy performed in the MUMC+ with a follow-up of at least one year and age above 18 years old. Exclusion criteria were patients with thymic carcinomas, refused participation, or those who were lost to follow-up.
Results: Of the 102 included thymoma-patients, 87 patients (85%) were tested for anti-AChR-antibodies before thymectomy, of which 57 patients were diagnosed with clinical MG and seven subclinical MG-patients were found. Of the 15 patients who were not tested for anti-AChR-antibodies, four more subclinical MG-patients were discovered in the years after thymectomy. The median follow-up time was 62 months. In total, 11 subclinical MG-patients were found, with a mean age of 54 years and predominantly females (64%). Ten subclinical MG patients (91%) developed clinical-MG, within six years after thymectomy. Immunosuppressive drugs were prescribed in five patients. Four patients were diagnosed with a recurrence of the thymoma. No surgical mortality was reported. Two patients died due to a myasthenic crisis.
Conclusions: The prevalence of subclinical MG in thymomas was found to be 10.8%. One in four patients who experienced no neurological symptoms before thymectomy, appeared to have anti-AChR-antibodies and 91% of these patients developed clinical MG within 6 years after the thymectomy. Analyzing anti-AChR-antibodies in the serum is recommended in all suspected thymomas before a thymectomy is performed.
Keywords: Thymomas, thymectomy; subclinical myasthenia gravis (subclinical MG); anti-AChR-antibody
Acknowledgments
Funding: None.
Conflicts of Interest: The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
doi: 10.21037/med.2021.ab001
Cite this abstract as: Marcuse F, Hochstenbag M, Hoeijmakers JGJ, Abdul Hamid M, Damoiseaux J, Maessen J, De Baets M. AB001. Subclinical myasthenia gravis in thymomas. Mediastinum 2021;5:AB001.
