Three Cases of Erdheim-Chester Disease with Intraocular Manifestations: Imaging and Histopathology Findings of A Rare Entity

Abstract Purpose To report intraocular manifestations of ECD with multimodal imaging. Design A retrospective observational case series. Methods This was a multi-center case series of three patients with confirmed tissue diagnosis of ECD that showed intraocular manifestations and were imaged at baseline and follow-up visits. Results Intraocular manifestations are rarely observed in association with Erdheim-Chester disease (ECD). Intraocular manifestations of ECD seen on multi-modal imaging include histiocytic choroidal infiltration causing choroidal lesions, complicated by recurrent serous retinal detachment (SRD). Short-term resolution of SRD was observed with ocular therapies including intravitreal injections of anti-vascular endothelial growth factor or verteporfin photodynamic therapy in combination with systemic chemotherapy therapies and oral corticosteroids; however, recurrences were common. Chorioretinal biopsy confirmed the diagnosis of ECD in one case, with the presence of histiocytic infiltration, fibrosis and characteristic immunohistological staining. In another case, with a novel ARAF positive mutation, treatment with sorafenib showed regression of the choroidal lesions and resolution of the SRD on multimodal imaging. These lesions were previously resistant to other forms of therapy. Conclusions Rare intraocular manifestations of ECD confirmed on histopathology can be imaged with multimodal imaging. We report three cases, including one case diagnosed through histology from chorioretinal biopsy and another case associated with a novel ARAF mutation responsive to targeted therapy with sorafenib. The identification of novel somatic mutation associated with ECD enabled treatment with a new-targeted systemic agent. Multimodal imaging in these cases can also be used to monitor response to therapy.