The authors present a single case of an 84-year-old man with arteritic anterior ischaemic optic neuropathy, but with unusual features on temporal artery biopsy. He presented with a three-day history of sudden onset of loss of vision in his right eye, headaches, weakness, myalgia and scalp tenderness. His visual acuity was no light perception in the right eye and 20/200 in the left eye. On further examination he demonstrated unusual histopathological findings for giant cell arteritis on temporal artery biopsy. Further systemic manifestations occurred three months later with lung nodules, renal dysfunction and sinusitis. A probable diagnosis of polyangiitis overlap syndrome was made and he was treated with steroids and an immunomodulator. The authors suggest this case could belong to a subgroup of systemic vasculitis and conclude that systemic evaluation and careful follow-up should be considered in cases where unusual histopathological features are found on temporal artery biopsy.