Metastatic Thymoma-Associated Myasthenia Gravis: Favorable Response to Steroid Pulse Therapy Plus Immunosuppressive Agent

Abstract

BackgroundOur study retrospectively reviewed the therapeutic effect of steroid pulse therapy in combination with an immunosuppressive agent in myasthenia gravis (MG) patients with metastatic thymoma.Material/MethodsMG patients with metastatic thymoma that underwent methylprednisolone pulse therapy plus cyclophosphamide were retrospectively analyzed. Patients initially received methylprednisolone pulse therapy followed by oral methylprednisolone. Cyclophosphamide was prescribed simultaneously at the beginning of treatment. Clinical outcomes, including therapeutic efficacy and adverse effects of MG and thymoma, were assessed.ResultsTwelve patients were recruited. According to histological classification, 4 cases were type B2 thymoma, 3 were type B3, 2 were type B1, and 1 was type AB. After combined treatment for 15 days, both the thymoma and MG responded dramatically to high-dose methylprednisolone plus cyclophosphamide. The symptoms of MG were improved in all patients, with marked improvement in 6 patients and basic remission in 4. Interestingly, complete remission of thymoma was achieved in 5 patients and partial remission in 7 patients. Myasthenic crisis was observed in 1 patient and was relieved after intubation and ventilation. Adverse reactions were observed in 7 patients (58.3%), most commonly infections, and all were resolved without discontinuation of therapy. During the follow-up, all patients were stabilized except for 1 with pleural metastasis who received further treatment and another 1 who died from myasthenic crisis.ConclusionsThe present study in a series of MG patients with metastatic thymoma indicated that steroid pulse therapy in combination with immunosuppressive agents was an effective and well-tolerated for treatment of both metastatic thymoma and MG. Glucocorticoid pulse therapy plus immunosuppressive agents should therefore be considered in MG patients with metastatic thymoma.

Thymoma‐associated myasthenia gravis: Clinical features and predictive value of antiacetylcholine receptor antibodies in the risk of recurrence of thymoma

“…Furthermore, the literature data show that presurgical steroid treatment enhances the effectiveness of thymectomy 18 and reduces the occurrence of relapses. 15 Our data suggest that the recurrence-free survival probability at 10 years is around 0.78 overall and 0.96, 0.83 and 0.41 in Masaoka-Koga stages I/IIa, IIb and III/IV, respectively.…”

“…Moreover, it is possible that in these patients the apoptotic effect of corticosteroids on the lymphocyte component of the tumors is more evident because of the longer MG history. 15 This result indicates the necessity of a stricter surveillance in young patients with thymoma.…”

“…We speculate that thymoma in the elderly arises from a thymic tissue that already underwent modifications towards apoptosis and tissue atrophy reducing its aggressiveness. Moreover, it is possible that in these patients the apoptotic effect of corticosteroids on the lymphocyte component of the tumors is more evident because of the longer MG history 15 . This result indicates the necessity of a stricter surveillance in young patients with thymoma.…”

“…This could be attributed to the beneficial effect on myasthenia gravis of higher doses of steroids administered in these patients in preparation for surgery to control myasthenic symptomatology. Furthermore, the literature data show that presurgical steroid treatment enhances the effectiveness of thymectomy 18 and reduces the occurrence of relapses 15 …”

Spontaneous resolution of metastatic thymoma with prednisone in a patient with juvenile myasthenia gravis: a case report

“…However he unexpectedly had spontaneous resolution of his large tumor burden with prednisone. There are scattered reports of metastatic thymoma in adult MG improving with high dose steroids (8)(9)(10). However, invasive metastatic thymomas are extremely rare in the pediatric population and have not…”