Tubular aggregates in autoimmune Lambert-Eaton myasthenic syndrome.
Tubular aggregates are accumulations of densely packed tubules in muscle fibers, occurring in distinct hereditary and acquired disorders. We present a patient with tubular aggregates and autoimmune Lambert-Eaton myasthenic syndrome. Initially, he showed mild proximal weakness, borderline decrement on 3 Hz stimulation, and slightly elevated creatine kinase. Muscle biopsy revealed tubular aggregates in type II fibers. Due to a good response to pyridostigmine, a limb-girdle myasthenia with tubular aggregates was suspected, but genetic analyses of GFPT1, DPGAT1, and ALG2 were normal. Two years later, the patient presented with progressive weakness and autonomic dysfunction. 17% decrement on 3 Hz stimulation and 100% increment after brief exercise were revealed. Autoantibodies to voltage-gated calcium-channels confirmed the diagnosis of Lambert-Eaton myasthenic syndrome. Steroids, azathioprine, and 3,4-diaminopyridine significantly improved symptoms. No tumor was found during follow-up. This is the first report about tubular aggregates associated with an acquired myasthenic syndrome. Our findings are important because of the therapeutic implications.
Department of Neurology, RWTH Aachen University, Aachen, Germany; Institute of Neuropathology, RWTH Aachen University, Aachen, Germany.
Isabell
I
Cordts
Institute of Neuropathology, RWTH Aachen University, Aachen, Germany; Department of Internal Medicine, Sankt Marien-Hospital Düren, Düren, Germany.
Fabian
F
Funk
Department of Neurology, RWTH Aachen University, Aachen, Germany; JARA - Translational Brain Medicine, JARA Brain Institute II, FZ Jülich and RWTH, Aachen, Germany.
Jörg B
JB
Schulz
Institute of Neuropathology, RWTH Aachen University, Aachen, Germany.
Joachim
J
Weis
Department of Neurology, RWTH Aachen University, Aachen, Germany; Institute of Neuropathology, RWTH Aachen University, Aachen, Germany; Department of Neurology, University Hospitals Leuven and University of Leuven (KU Leuven), Leuven, Belgium. Electronic address: kristl.claeys@uzleuven.be.
Kristl G
KG
Claeys
D000328:Adult; D003937:Diagnosis, Differential; D015444:Exercise / Q000502:physiology; D006801:Humans; D015624:Lambert-Eaton Myasthenic Syndrome / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology
Acquired; Lambert–Eaton myasthenic syndrome; Muscle biopsy; Tubular aggregates