Rituximab for refractory ocular symptoms in myasthenia gravis with thyroid eye disease: a case report with quantitative MRI assessment

Aims To report a case with concurrent myasthenia gravis (MG) and thyroid eye disease (TED) showing response to rituximab (RTX) through both clinical evaluation and quantitative MRI assessment. Methods A 31-year-old female patient with refractory ocular symptoms from concurrent MG and TED received RTX after failing multiple conventional treatments. Treatment response was evaluated through clinical scores and quantitative T2 mapping of extraocular muscles (EOMs) before and after RTX administration. Results Following RTX treatment, the patient achieved corticosteroid-free remission by six months post-RTX, with Myasthenia Gravis Activities of Daily Living score decreasing from 5 to 0, complete resolution of ptosis, and improvement in ocular motility and exophthalmos. Quantitative T2 mapping demonstrated significant reductions in T2 relaxation times (10.6%-20.9%) across all EOM regions of interest, with decreased standard deviations indicating restored tissue homogeneity. Conclusions This case suggests potential therapeutic benefit of RTX for refractory ocular symptoms in concurrent MG and TED. Quantitative T2 mapping revealed pathologically elevated values that normalized post-treatment, providing preliminary objective evidence of treatment response. As a single case, the relative contributions of MG versus TED pathology cannot be definitively separated. Integrating clinical assessment with quantitative T2 mapping may offer an objective approach for monitoring treatment response in such complex dual autoimmune disorders.