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Título

Recidived Thymolipoma approach for Myasthenia gravis fatigability control: Case Report

RESUMO

Case presentation: A 26-year-old woman presented to our Neurologic Emergency Department, referring unilateral ptosis and dysphagia associated with fatigability of shoulder girdle muscle compartment as a myasthenic syndrome was hypothesized. Lately, neurophysiologic study with Electromyoneurography (EMNG) and humoral analysis of autoantibodies has been positive (anti-AchR 1,0 nmol/L), suggesting autoimmune Myasthenia gravis diagnosis. Despite using Immunomodulators such as Azathioprine, Glucocorticoid therapy, Therapeutic Plasma Exchange (TPE) and Intravenous Immunoglobulin (IVIG) in addition to pyridostigmine, the patient remained with the breakthrough symptoms (Osserman Classification IV) and specialists proposed a thymectomy while an attempt to control the ectopic secretion of antibodies. The patient underwent the mediastinal mass removal (12 x 10 x 2.5 cm) with posterior histopathological analysis of disclosed thymic gland tissues with an abundant mature adipose tissue, suggesting a rare neoplasm thymolipoma, considered a possible factor with humoral discharge. After surgical excision, there was partial maintenance of symptoms for a certain period, with recurrence of the tumor evidenced by a CT scan approximately 04 years after the procedure, performing a re-thymectomy proposal through thoracoscopy approach for clinical control. Thenceforth, she has moderate fatigability with immunotherapy, avoiding clinical decompensation such as diaphragmatic loss in myasthenic crisis.

Discussion: Myasthenia gravis (MG) is a neuromuscular transmission disorder resulting from the binding of autoantibodies to components of the neuromuscular junction (NMJ), most commonly the acetylcholine receptor (AChR). These autoantibodies are directly responsible for the pathological change in the endplate - being dependent on CD4+ T and B cells. The incidence of Thymolipoma is around 0.12 out of 100.000 cases per year, including 34 documented cases reporting the association between Myasthenia gravis and this specific tumor. The exact mechanisms remain unclear; however, there is guidance for en bloc resection of all anterior mediastinal tissue in order to symptomatic control.

Conclusion: In this presentation, we describe a patient with refractory Myasthenia gravis, leaving the usual pattern of clinical control and suggesting the importance of the thymus in the pathophysiology. However, the complete remission rate of symptoms needs further studies for a reliable conclusion.

Palavras Chave

Myasthenia gravis; Thymolipoma; Thymectomy