Rituximab Monotherapy Is Effective in Treating Orbital Necrobiotic Xanthogranuloma

The authors report a case of a patient with bilateral orbital necrobiotic xanthogranuloma and no associated systemic paraproteinemia. Orbital biopsy showed strong expression of CD20-positive cells. The patient was treated with systemic rituximab monotherapy, with excellent clinical response and marked regression of the orbital lesions on imaging. At the time of writing, the patient has been treated with bimonthly rituximab maintenance therapy for 22 months and has stable clinical and imaging findings with sustained response to treatment and no reported side effects. To the authors' knowledge, this is the first reported case of orbital necrobiotic xanthogranuloma successfully treated with rituximab monotherapy. They hope that this well-documented case will encourage clinicians to consider rituximab monotherapy as a possible treatment option, albeit one entailing an off-label use of this drug, for patients with necrobiotic xanthogranuloma of the orbit.