The relationship between spider naevi & de novo arteriovenous malformations in chronic liver disease.

We report a patient with decompensated alcoholic liver cirrhosis (Child-Turcotte-Pugh class C) who developed a left frontal cerebral AVM and a subcutaneous left temporal scalp spider naevus. Arteriovenous malformations (AVMs) are vascular abnormalities previously thought to be congenital in nature, although new research has revealed the potential for AVM formation through a two-hit hypothesis. We propose that the oestrogen-rich environment seen in chronic liver disease could act as the second hit to allow for an angiogenic state favouring AVM development. We also postulate that spider naevi are formed through a similar mechanism and may represent early-stage AVMs.