Analysis of outcomes following surgical treatment of thymolipomatous myasthenia gravis: Comparison with thymomatous and non-thymomatous myasthenia gravis

Objectives: Although significant improvement in myasthenic symptoms has been reported following the removal of thymolipomas, information on surgical outcomes among patients with thymolipomatous myasthenia gravis (MG) is limited. Methods: This was a retrospective review of patients who underwent extended thymectomy for treatment of MG. Results: From 1995 to 2010, 267 patients with MG underwent extended thymectomy, including 104 with thymomatous MG, 151 with non-thymomatous MG and 12 (4.4%) with thymolipoma. The mean duration of myasthenic symptoms before surgery was greatest in the thymolipomatous group (P < 0.001). The lowest mean age (36.1 years old, P < 0.001) and the lowest preoperative serum anti-acetylcholine receptor antibody titre (P = 0.015) occurred in the non-thymomatous group. More thymic and adipose tissue was removed from the thymolipomatous group compared with the non-thymomatous group (P < 0.001). Regarding surgical outcomes, the rate of stable remission was higher in the non-thymomatous (42.3%) and thymolipomatous (41.7%) groups compared with the thymomatous group (28.8%, P = 0.029). No instances of postoperative exacerbation of MG or tumour recurrence were noted during the postoperative follow-up of patients treated for thymolipoma. Conclusions: Our results suggest that patients with myasthenia thymolipomatous have surgical outcomes similar to those of patients with non-thymomatous MG and have a mean age at the time of surgery similar to that of patients with thymomatous MG.