Behind the Curtain

Our patient had aggressive systemic inflammatory pseudotumor presenting initially as ocular myasthenia gravis. The standard chest imaging following the diagnosis of myasthenia enabled recognition of diffuse inflammation several years before other systemic signs and symptoms became apparent. Pathology from numerous biopsies ruled out lymphoma or other malignancies. Despite the prominent fibrotic background, the lesions did not meet current criteria to be considered the IgG4-related sclerosing form of inflammatory pseudotumor. Throughout the patient's course, the AChR blocking antibody titer correlated with his overall systemic inflammatory state. The titer at the initial presentation of isolated ocular myasthenia gravis was 6.6 um/L. It peaked two years later at 11.9 um/L, coincident with the recurrence of ptosis and diplopia, as well as the evolution of diverse signs of systemic autoimmunity, including orbital inflammatory syndrome, inflammatory scalp masses, and autoimmune hemolytic anemia. The antibody titer decreased markedly (and ranged from 1.2 to 1.7 um/L), and all clinical signs of systemic autoimmunity resolved, upon initiating bimonthly rituximab. The switch to monthly rituximab, prompted by the appearance of autoimmune glomerulonephritis, led to complete disappearance of detectable AchR antibody.