Koenen tumours revealing tuberous sclerosis complex in late adulthood

A 65-year-old man presented with painful, decades-long periungual and subungual tumours affecting multiple toenails, with nail dystrophy, subungual hyperkeratosis and walking discomfort. Recognition of these Koenen tumours, together with subtle facial angiofibromas, fibrous plaques, multiple renal cysts and longstanding refractory epilepsy, supported a clinical diagnosis of tuberous sclerosis complex.