Sarcoidosis in a case of MuSK-positive myasthenia gravis.

Whereas the coexistence of different autoimmune or rheumatologic diseases with myasthenia gravis is well documented, the combination of myasthenia with sarcoidosis is extremely rare. There very few case reports of patients suffering from these two immune-mediated diseases. Nearly all had acetylcholine receptor antibodies. As far as we know myasthenia gravis with antibodies to muscle-specific tyrosine kinase-MuSK--has not been associated with any form of sarcoidosis. We present probably the first case of MuSK-positive myasthenia gravis with concurrent, asymptomatic pulmonary sarcoidosis.