Abstract
Purpose :
Rituximab is a monoclonal antibody that targets CD20 receptors present in the B-cell membranes. This commercially available drug is used in a variety of diseases including rheumatoid arthritis, non-Hodgkin’s B-cell lymphomas, granulomatosis with polyangiitis (GPA; Wegener’s granulomatosis), in addition to orbital inflammatory diseases such as inflammatory pseudotumor and IgG4-related disease (IgG4RD). The purpose of this study is to describe a unique orbital histopathological finding in patients treated with rituximab for granulomatosis with polyangiitis (GPA) and orbital pseudotumor.
Methods :
We conducted a retrospective review of all patients diagnosed with orbital GPA, inflammatory pseudotumor, and IgG4RD at the Mayo Clinic in Rochester, MN from September 1st, 1994 through July 1st, 2017. Inclusion criteria were that the patient’s orbital disease was treated with rituximab and that a biopsy specimen following rituximab therapy was available to review. Patients were excluded if they did not have a second biopsy following rituximab therapy or if they were being treated with rituximab for other diseases.
Results :
The initial search yielded 16,136 patients with GPA, ocular pseudotumor, and orbital IgG4RD. There were 23 patients that had an orbital biopsy following rituximab therapy. Of these patients, 6 had unique findings in the biopsy not previously described (5 GPA patients, and 1 with orbital pseudotumor. There were 4 females (66.7%) and the mean age at biopsy was 57.8 ± 15.6 years. The mean time from rituximab therapy to biopsy was 73.2 ± 46.2 days with a median follow up of 57 months after the biopsy (7.75, 157). The clinical indication for the biopsies were: pain (3 patients), new mass lesion (2 patients), and non-diagnostic initial biopsy at an outside institution (1 patient). Review of the biopsies showed marked collagenized fibrous tissue, with areas of concentric fibrosis resembling the framework of pre-existing lymphoid follicles and minimal residual lymphocytic infiltrates. Entrapped nerves were observed that could account for the patients’ pain. The cases of GPA had residual active vasculitis with scattered neutrophils.
Conclusions :
To the best of our knowledge, this is the first histological description of the tissue effects of treatment with rituximab. As expected, the re-biopsies show mostly scarring as result of the B-cell infiltrate depletion caused by this medication.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.