Cowden syndrome with Lhermitte–Duclos disease presenting as ataxia.

Cowden syndrome or multiple hamartoma syndrome is a rare genodermatosis of autosomal dominant inheritance characterized by multiple hamartomatous lesions of ectodermal, mesodermal and endodermal origin. A 45-year-old man presented to us with a history of dural arteriovenous fistula and intracerebral bleed in the past with gradually progressive difficulty in walking. Magnetic resonance imaging (MRI) of the brain showed a heterogeneous lesion in the cerebellum which was diagnosed as adult Lhermitte–Duclos disease which is considered a component of Cowden syndrome. On examination we found florid skin and mucosal manifestations of Cowden syndrome. A family history of thyroid malignancy was also present. Using the Cleveland Clinic web calculator, the patient had an 82% chance of having a phosphatase and tensin homologue (PTEN) mutation.