Myasthenia gravis associated with invasive malignant thymoma: two case reports and a review of the literature

Abstract

IntroductionApproximately ten to fifteen percent of patients with myasthenia gravis are found to have a thymoma, and twenty to twenty-five percent of patients with thymoma have myasthenia gravis. Thymomatous myasthenia gravis tends to have a difficult clinical course and poor prognosis.Case presentationWe report two cases (one patient of Asian ethnicity and the other of Caucasian ethnicity) of atypical presentations of myasthenia gravis associated with invasive malignant thymoma. Both patients were diagnosed at a young age, in their 20s. They presented with a turbulent course of myasthenia gravis and recurrent thymoma, but obtained good outcome after aggressive treatment involving multiple different specialists.ConclusionsAlthough thymomatous myasthenia gravis tends to have a difficult clinical course and poor prognosis, early and aggressive treatment along with multidisciplinary management may improve the outcome of these patients.

Malignant Thymoma with Metastasis Associated with Paraneoplastic Myasthenia Gravis

“…Our patient showed drastic symptomatic improvement after undergoing fi ve rounds of plasmapheresis. Moderate MG symptom improvement has been reported with removal of thymic carcinoma metastases to the pleura (8). Unfortunately, our patient was not a surgical candidate due to multiple extrathoracic metastases.…”

“…A small biopsy cannot adequately demonstrate the mixed histology that can be present. Metastasis from thymic tumors is most commonly seen in lymph nodes, liver, and soft tissue/skeletal muscles, with other sites including bone, brain, and abdominal wall (8)(9)(10)(11).…”

A Case Series of Patients With Autoimmune Myasthenia Gravis in Association With Invasive Thymoma

“…23 Our high mortality rate is comparable with that found in a study of 19 Other recent reports of MG with invasive thymoma described good outcome in 2 patients. 21 The patients who died in our series had uncontrolled respiratory failure. In a study of 8 patients with MG who died with thymoma, in 6 the cause of death was exacerbation of MG. 20 As already mentioned, in patients with thymoma with MG, the outcome is related to the ability to achieve clinical remission of MG. 17 All our patients were AChR Ab positive.…”

“…One study found that the presence of invasive thymoma with MG is associated with worse prognosis than invasive thymoma alone, 18 which indicates that the prognosis is influenced by the additional issues associated with MG, and some other small case series report outcomes. [19][20][21] We present the clinical characteristics of 6 subjects with MG and invasive thymoma, to demonstrate the clinical course and the outcome.…”

Pleural “drop metastases” 21 years after resection of a thymoma

“…Approximately 10%–20% of patients with MG are found to have a thymoma . In the United States, the incidence of thymoma is 0.15 per 100,000 person‐years, and it is highest among Asians, Pacific Islanders, and African Americans …”