Optic neuropathy caused by orbital Kimura disease: A rare case report

Rationale: Kimura disease (KD) is a rare, chronic inflammatory disease characterized by painless subcutaneous nodules predominantly located in the head and neck regions. Orbital KD, which intrudes into the intraconal space and results in compressive optic neuropathy, is rare and has not been previously reported. Patient concerns: A 68-year-old man presented with blurred vision and progressive proptosis in the left eye that had been present for 2 years. Diagnosis: Magnetic resonance imaging of the brain revealed soft tissue lesions with contrast enhancement and restricted diffusion involving the bilateral eyelids, orbits, and intraconal region; those on the left side were more prominent than those on the right side. The lesion encased the left optic nerve. Laboratory test results revealed elevated serum immunoglobulin E level and peripheral eosinophilia. An orbital mass biopsy demonstrated hyperplastic lymphoid follicles with germinal centers in the subcutaneous area and abundant mononuclear and binuclear eosinophils infiltrating the interfollicular area. A pathological diagnosis of KD was made based on the blood test results. Interventions: Orbital decompression and debulking surgery of the orbital tumor in the left eye were performed to treat the compressive optic neuropathy. Outcomes: After systemic oral steroid and immunosuppressive agent therapies, the patient's visual acuity in the left eye improved, and the KD activity was stable. Conclusions: We present a rare case of orbital KD-associated optic neuropathy, wherein early diagnosis and treatment preserved the patient's vision. This complication should be considered in patients with a history of compressive optic neuropathy during the differential diagnosis.