Definitive radiotherapy for meningeal brainstem melanocytoma: a case report

Meningeal melanocytomas are rare, benign tumours of the central nervous system arising from the melanocytes of the leptomeninges. First-line treatment consists of either gross or subtotal resection with or without radiotherapy. However, given the sensitive locations of these tumours, alternative treatment options such as definitive radiotherapy may be warranted in patients deemed high-risk or without accessible tumours. A 67-year-old male presenting with spastic gait, frequent falls, and vertical gaze palsy was diagnosed with a 2.4 cm primary meningeal melanocytoma arising from the interpeduncular fossa. Given the critical tumour position within the brainstem, definitive radiotherapy was recommended. He received fractionated stereotactic radiotherapy (FSRT) to a total dose of 54 Gy in 27 fractions, resulting in a gradual improvement in gait and ocular range of motion. Follow-up imaging over the next three years revealed largely stable disease and an increase in edema with mild upper extremity weakness that improved with steroids. He was followed for three years and expired four years after treatment due to pneumonia. For patients unable to receive surgical resection, definitive RT may provide local control with minimal morbidity.