Myasthenia Gravis: A Paraneoplastic Syndrome Linked to Renal Cell Carcinoma?
Posted: Thursday, August 26, 2021
The autoimmune disorder myasthenia gravis affects neuromuscular junctions and is mainly associated with thymoma, although associations with other malignancies may be possible but not well understood. An article published in BMC Neurology highlighted findings after Chinese investigators examined associations between myasthenia gravis and renal cell carcinoma and whether the former occurred as a paraneoplastic syndrome or not. Feng Gao, MD, of Peking University First Hospital, Beijing, and colleagues reported six cases of myasthenia gravis in patients with renal cell carcinoma, with four meeting the diagnostic criteria of possible paraneoplastic neurologic syndromes.
Medical data from 283 patients diagnosed with myasthenia gravis from 2014 to 2019 were initially examined for this study. Patients included 127 males and 156 females. Among them, a total of six patients were diagnosed with renal cell carcinoma. These patients were included in a more thorough analysis of retrospective clinical data, and follow-up studies were conducted.
The data revealed an average myasthenia gravis onset age of 61.3 ± 13.3 (39–76) years. For three patients, myasthenia gravis symptoms appeared after resection for kidney cancer. However, renal malignancy was discovered after myasthenia gravis onset in two other cases and synchronously in one other case. After radical nephrectomy, myasthenia gravis symptoms showed a stable complete remission in one case, but the other patients, who were also treated with immunosuppressants, had very different outcomes. Three patients showed signs of partial improvement, whereas the condition for the other two remained unchanged. According to the recommended diagnostic criteria for paraneoplastic neurologic syndromes, four patients met the criteria for possible diagnosis.
Based on their findings, Dr. Gao and colleagues concluded that patients with myasthenia gravis and their physicians should pay attention to other extrathymic malignancies, including renal cell carcinoma. Further studies are needed to understand this potential relationship better.
Disclosure: The study authors reported no conflicts of interest.