Orbital Involvement in Multiple Myeloma

Purpose:To characterize clinical and radiographic features, management, and outcomes of patients with orbital involvement of multiple myeloma (MM). Methods:A retrospective chart review identified patients with MM and orbital involvement confirmed by histopathology at a single institution between 1995 and 2021. A comprehensive literature review was performed via PubMed to identify all previously reported cases of orbital MM. Results:Retrospective review identified 7 patients (43% male, mean age 68.7 years). Presenting symptoms included proptosis and diplopia. Orbital lesions were primarily located laterally (42.8%) with associated extraocular muscle (57.1%) or lacrimal gland (42.9%) involvement. Five patients (71.4%) had a previous diagnosis of systemic MM. Six patients received chemoradiation (85.7%). All patients had improvement of orbital disease with 2 patients deceased due to disease at follow-up (mean 8.9 months). Literature review identified 111 cases (46.8% male, mean age 58.6 years). 48.6% presented with orbital disease as the first manifestation of systemic MM. Lesions were most commonly located superolaterally (20.2%) with extraocular muscle infiltration (25.2%), lacrimal gland involvement (7.2%), and orbital bony destruction (39.6%). Treatments included chemoradiation, chemotherapy, or radiation alone. Approximately half (51.4%) of patients experienced improvement in orbital disease following treatment, and 48.6% were deceased at follow-up (mean 20.1 months). Conclusions:This study provides a new retrospective study and updated comprehensive literature review regarding orbital MM. Given its poor prognosis, characterization of orbital MM is essential for early diagnosis. Orbital MM is often unilateral, located superolaterally, and may represent the first manifestation of systemic disease. Treatment includes chemotherapy and radiation, which may improve orbital disease; however, the overall prognosis remains poor.