Simultaneous and sustained remission of intractable myasthenia gravis and focal segmental glomerulosclerosis with tacrolimus treatment

Nephropathies associated with thymoma or myasthenia gravis (MG) have rarely been observed. Furthermore, among the renal pathology of patients presenting with thymic and renal disease, focal segmental glomerulonephritis (FSGS) is the uncommon type. Herein, we report a case of a 50-year-old woman who suffered from intractable MG and FSGS resistant to standard therapy. After the start of low-dose tacrolimus treatment, the patient showed simultaneous and significant improvement of myasthenic symptoms and proteinuria. Although a satisfactory explanation of the underlying mechanism has not been offered yet, T cell dysfunction involved in both diseases might explain their association and improvement. This case suggests that low-dose tacrolimus treatment appears to be effective not only for improving intractable myasthenia symptoms but also for obtaining complete remission of FSGS.