Seronegative myasthenia gravis and familial Hodgkin's disease.

A 29-year-old woman developed a seronegative myasthenia gravis. A thorax CT scan demonstrated an anterior mediastinal mass. Thoracotomy showed a lymphofollicular thymic hyperplasia and Hodgkin's disease of the nodular sclerosing type with mediastinal lymph node localisation. This patient's brother had been suffering as well from Hodgkin's disease. Epidemiological similarities (genetic influences and the role of a viral agent) between Hodgkin's disease and myasthenia gravis and the immune abnormalities found in these two diseases suggest that their association is not fortuitous.