A Case of Multi-System Langerhans Cell Histiocytosis with Local Invasion of the Orbital Apex

Langerhans cell histiocytosis (LCH) is characterised by tissue destruction caused by the abnormal proliferation of pathogenic dendritic cells. We report a rare case of multi-system LCH with local invasion of the orbital apex. A 56-year-old woman suffered from a decrease of visual acuity in the left eye caused by central scotoma and the limitation of eye movement in all directions. Magnetic resonance imaging revealed an enhanced lesion in the left orbital apex, suggesting optic nerve compression. She had been diagnosed with eosinophilic granuloma 24 years previously. Two weeks after the current presentation, we admitted the patient for optic canal and orbital apex decompression and subtotal tumour resection. Histopathological analysis confirmed the diagnosis of LCH. Post-surgical treatment with low-dose cytarabine was initiated for the residual tumour. However, it was ceased because of myelosuppression-induced pyelonephritis. After surgery, the central scotoma disappeared on day 5 and eye movement palsy resolved by 6 months. After the cessation of cytarabine, she has received low-dose steroid therapy for 2 years with no recurrence. Early surgical intervention with low-dose steroid therapy can lead to recovery of visual acuity and resolve eye movement palsy in patients with lesions of the orbital apex caused by multi-system LCH.