en Biomarkers (diagnosis & treatment) Biomarkers (diagnosis & treatment) Case Report Case Report <div style="text-align: justify;">Myasthenia Gravis (MG) is a neuromuscular junction disorder caused by pathogenic autoantibodies to some parts of the post-synaptic muscle endplates. About 85% of generalized MG patients have autoantibodies against post-synaptic acetyl-choline receptors (AChR). From the 10-15% of the remaining patients, 45-50% are positive for Muscle Specific Tyrosine Kinase-Antibody (MuSK-Ab). It is believed that the thymus has a critical role in the pathogenesis of the disease with AChR-Ab, especially in patients with thymic abnormalities. In contrast, the role of thymus gland in MG with anti-MuSK-Ab is not clearly obvious. Patients with this antibody virtually have normal or only minimal follicular hyperplastic thymus. The presence of anti-MuSK Ab in a thymolipomatous (an uncommon tumor of thymus) MG is an atypical and new finding of MG because of not only thymolipoma but also presence of anti-MuSK antibodies which makes this case different from the previous reports of the antibodies-associated MG.&nbsp; Here, we present a young woman with thymolipoma and MG (a very uncommon kind of tumor-associated MG) and high level of anti-MuSK-Ab.</div> Myasthenia gravis, thymolipoma, anti-acetylcholine receptor antibody, anti-Muscle Specific Tyrosine Kinase-Antibody 90 93 http://ijmcmed.org/browse.php?a_code=A-10-1790-1&slc_lang=en&sid=1 Maryam Poursadeghfard poursadra@gmail.com 100319475328460016013 100319475328460016013 Yes Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. Amin Abolhasani Foroughi foroughiaa@sums.ac.ir 100319475328460016014 100319475328460016014 No Medical Imaging Research Center, Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran. Sina Karamimagham karamimagham@gmail.com 100319475328460016015 100319475328460016015 No Specialty in neonatology, Shiraz University of Medical Sciences, Shiraz, Iran.