The first patient had edema and chemosis more pronounced in the left eye, with stretching of the optic nerve on orbital computed tomography due to marked periorbital tissue swelling (Figure 1B). Visual acuity returned to normal (10/10), and significant decreases of edema and inflammation (CAS decreased from 5 to 3) and proptosis in both eyes (decreasing from 24.5 to 23 mm OD and from 31 to 28 mm OS) were observed the next day. A week later, the disease was inactive (CAS of 2) (Figure 1A and B). The second patient had marked orbital edema (Figure 1B) and visual loss (counting fingers) in the more severely affected eye (the left eye). Orbital computed tomography showed only swelling of the retro-ocular tissue. Visual acuity improved in 60 minutes; 3 hours later, visual acuity was 10/10. A week later, inflammation improved bilaterally (CAS decreased from 6 to 3) (Figure 1A) and proptosis decreased (decreasing from 27.5 to 26 mm OD and from 29.5 to 27 mm OS) (Figure 1B). The third patient had no infusion-related effect, and the GO became inactive at 8 weeks (CAS decreased from 6 to 3). No disease relapse was observed in the patients at 32, 55, and 86 weeks of follow-up, respectively. Sixty minutes after treatment with 100 mg of rituximab, we recorded depletion of peripheral CD20+ and CD19+ cells (Figure 1C), similar to what is observed after receiving a standard rituximab dose. Immunohistochemistry (Figure 2B) in steroid-treated and untreated patients has shown CD20+ or CD3+ orbital infiltrates of variable degree but complete depletion of CD20+ cells and near complete depletion of CD3+ lymphocytes after receiving a low dose of rituximab. Of note, after rituximab treatment, there was significant infiltration of CD68+ macrophages, no CD1a+ dendritic cells, and good expression of CD163, a marker of type 2 macrophages. Control patients had only focal CD68+ and CD163+ cell infiltration.