But the NHS warns: “The concern is that Bowen’s disease can eventually develop into a different type of skin cancer called squamous cell skin cancer if left undiagnosed or neglected. “This is estimated to occur in up to one in 20 to one in 30 people with untreated Bowen’s disease. “Squamous cell skin cancer is often treatable, but it can spread deeper in the body and is sometimes very serious.” READ MORE: Dementia: Symptoms that can appear at night – ‘sunset’ signs