A diagnostic and management dilemma: combined paraneoplastic myasthenia gravis and Lambert-Eaton myasthenic syndrome presenting as acute respiratory failure.
BACKGROUND
Neuromuscular junction disorders are usually categorized as either presynaptic or postsynaptic. The most frequently encountered disorder of the postsynaptic neuromuscular junction is acquired myasthenia gravis. Lambert-Eaton myasthenic syndrome is a well-known prototype of the presynaptic autoimmune disorders of neuromuscular transmission. These major disorders of neuromuscular transmission are relatively common and distinctly recognized, but co-occurrence of these disorders (overlap myasthenic syndrome) is rare and has so far attracted little attention.


RESULTS
This report describes a patient with acquired myasthenia gravis and immunologic coexistence of Lambert-Eaton myasthenic syndrome (overlap myasthenic syndrome) in association with abdominal/uterine leiomyosarcoma. The patient presented with acute respiratory failure, making identification and management of her illness challenging. A general overview of the complexities associated with overlap between myasthenia gravis and Lambert-Eaton myasthenic syndrome is provided and this patient's complicated clinical course and response to therapy are discussed.


CONCLUSIONS
To our knowledge, this is the first report of overlap myasthenic syndrome in conjunction with abdominal leiomyosarcoma. The immunologic coexistence of acquired myasthenia gravis and Lambert-Eaton myasthenic syndrome in a patient with a malignant smooth-muscle tumor is intriguing and suggests that a common paraneoplastic process targeting 2 different onconeural antigens was the underlying pathogenic mechanism in this patient.
Roohi
Fereydoon
F
Department of Neurology and the Division of Pulmonary Medicine, Long Island College Hospital, Brooklyn, New York 11201, USA. froohi@chpnet.org
Smith
Peter R
PR
Bergman
Michael
M
Baig
Muhammad A
MA
Sclar
Gary
G
D000368:Aged; D005260:Female; D006801:Humans; D015624:Lambert-Eaton Myasthenic Syndrome / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D009157:Myasthenia Gravis / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D012131:Respiratory Insufficiency / Q000209:etiology*