title: Seronegative myasthenia gravis associated with malignant thymoma.
abstract: Myasthenia gravis (MG) is generally caused by antibodies directed against the neuromuscular junction, including antibodies against the postsynaptic nicotinic acetylcholine receptor (AChR). Pathologic abnormalities of the thymus gland, including thymoma, are associated with MG. We report a 56-year-old woman who presented with double vision. Single fiber EMG confirmed myasthenia gravis. AChR, striational muscle and MuSK antibodies were absent in the serum. Chest CT demonstrated a malignant thymoma. We report the first case of seronegative myasthenia gravis associated with malignant thymoma. The case challenges the conventional wisdom that all patients with thymoma associated MG test positive for antibodies against AChR.
authors.affiliation: Department of Neurology, The University of North Carolina, Chapel Hill, NC 27514. Electronic address: Jason.Richards@unchealth.unc.edu.
authors.forename: Jason
authors.initials: J
authors.lastname: Richards
authors.affiliation: Department of Neurology, The University of North Carolina, Chapel Hill, NC 27514.
authors.forename: James F
authors.initials: JF
authors.lastname: Howard
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000097:blood / Q000150:complications* / Q000000981:diagnostic imaging / Q000188:drug therapy; D013945:Thymoma / Q000097:blood / Q000150:complications* / Q000000981:diagnostic imaging / Q000628:therapy; D013953:Thymus Neoplasms / Q000097:blood / Q000150:complications* / Q000000981:diagnostic imaging / Q000628:therapy
keywords: Autoimmune illness; Malignant thymoma; Myasthenia gravis