Symptoms of myasthenia gravis in a patient with a history of thymectomy for invasive thymoma

Lilliana María Giraldo, Camilo Duque, Carlos Santiago Uribe, Olga Helena Hernández

Myasthenia gravis is an antibody-mediated autoimmune disease. Approximately 10-15% of patients present with a thymoma, the presence of which is associated with greater severity of symptoms, myasthenic crisis, and irresponsiveness to front-line therapy. A thymectomy is recommended in young patients with generalized myasthenia gravis and in all patients presenting with thymoma. The patient was a 43-year-old woman, who first showed symptoms of myasthenic crisis in 2005 and presented with invasive thymoma managed with thymectomy and radiotherapy. In the subsequent three years, the patient presented with severe symptoms and two myasthenic crises that required mechanical ventilation and immunoglobulin treatment. Contrast chest computed tomography examinations showed no recurrence. Between 2009 and 2012, the patient experienced decreased symptom severity. In 2013, the patient presented with an exacerbation of symptoms; a contrast chest magnetic resonance scan showed a lesion in the anterior mediastinum, previously observed in 2011, suggestive of residual tissue as opposed to fibrosis. Regular management was started with immunoglobulins; a positron emission tomography scan was inconclusive, requiring a new resection, which showed no evidence of tumor recurrence. Patients with myasthenia gravis and those with myasthenia-related thymoma both share thymectomy as an element of treatment. However, following the procedure, exacerbation or reappearance of symptoms does not necessarily represent new alterations in the thymus.