MUSK and thymoma: Accordingly, multivariate analysis revealed that QMG score at diagnosis [OR 1.23 95% confidence interval (95%CI) 1.14–1.66, p < 0.0001], MGFA class at diagnosis (OR 1.83 95% CI 1.65–1.97, p < 0.001), anti-MuSK-ab (OR 2.18 95% CI 1.76–2.59, p < 0.05) and the presence of a thymoma (OR 3.71 95% CI 3.01–4.41, p < 0.0001) predicted the occurrence of MC as independent risk factors (Table 2).