Adult orbital xanthogranuloma: long-term follow-up of treated cases

Background: Adult orbital xanthogranulomatous disease (AOXGD) is a group of rare disorders. Four subtypes are identified: adult-onset xanthogranuloma (AOX), adult-onset asthma and periocular xanthogranuloma (AAPOX), necrobiotic xanthogranuloma (NBX), and Erdheim-Chester disease (ECD). Therapy options vary and little is known about the long-term effect of the treatment. In this study, we will describe the clinical behaviour, effect of treatment, and long-term outcome in a consecutive series of patients with AOXGD. Methods: This is a descriptive, retrospective study with a long follow-up term of 21 patients with histologically proven AOXGD, treated between 1989 and 2021 in the Rotterdam Eye Hospital and Erasmus MC University Medical Center. Results: Twenty-one patients with histologically proven AOXGD were included. The follow-up ranged from 2-260 months (median of 67 months). Six of the nine patients with AOX were treated with surgery alone, with recurrence in two. Three received systemic therapy, with recurrence in one. All four patients with AAPOX received systemic treatment, the disease recurred in two. Two patients with NBX were treated with surgery alone, with recurrence in one. Four required additional therapy with recurrence in two. Both patients with ECD required systemic therapy. Conclusions: Recognition of AOXGD is important, in particular, because of the potential severe systemic locations in the different subtypes. Surgical excision might be a sufficient therapy for patients with AOX. Patients with AAPOX, NBX, and ECD warrant systemic therapy. Currently, there is no conclusive evidence for a superior treatment strategy, but further studies are necessary to investigate treatment options.