Thymolipomatous myasthenia gravis outcomes following thymectomy: a systematic review

OBJECTIVES: Our goal was to evaluate the effect of thymectomy on the progression of thymolipomatous myasthenia gravis. METHODS: An electronic search performed across PubMed, MEDLINE and Web of Science databases included all article types. We included 15 series comprising 36 cases that met specific criteria, including case reports or case series related to thymolipoma with a myasthenia gravis association, where thymectomy was cited as the primary intervention with postoperative reporting of the prognosis and articles written in the English language. RESULTS: Our study included 17 men (47.2%) and 19 women (52.8%). Tumour sizes varied between 34 × 18 × 7 cm and 2.8 × 2.3 × 1.9 cm; the weight of the tumours ranged between 38 and 1780 g (mean 190, standard deviation 341). The surgical approaches were a median sternotomy in 29 patients (80.6%), a thoracotomy in 1 patient (2.8%), video-assisted thoracoscopic surgery in 2 patients (5.6%) and unreported approaches in 4 (11.1%) patients. The disease was entirely resolved with complete, stable remission in 5 patients (13.9%); symptoms were improved in 19 (52.8%) and stable in 10 patients (27.7%). We identified 2 groups of patients according to their improvement post-thymectomy (improved group and group with no change). CONCLUSIONS: Although the cases were uncontrolled and did not demonstrate strong associations, they do support some hypotheses. We found a significant statistical difference between the 2 groups in terms of age, because younger patients tended to improve to a greater degree post-thymectomy. Also, we found that female patients with thymoma visible on the imaging scans were significantly associated with post-thymectomy myasthenia gravis improvement. REGISTRATION NUMBER IN PROSPERO: CRD42020173229.