Summary

Cowden syndrome is a multiple hamartoma syndrome with a high risk of breast and thyroid tumours, both benign and malignant. The authors report a 24-year-old female patient who presented with reduced vision in both eyes. Ocular examination showed vitreous haemorrhage secondary to retinal new vessels in both eyes. There was no evidence of diabetes mellitus, and she had a wide range of normal investigations. She was labelled as idiopathic retinal neovascularisation. Fifteen years later, she presented with a lump in her left breast and a previous history of excision of a benign lump from her right breast. She also reported multiple tumours in her family. Clinical diagnosis of Cowden syndrome was made and genetic testing confirmed mutation of the PTEN gene.