Accumulation of membrane-bound melanosomes occurs in Langerhans cells of patients with the Leopard syndrome.

The Langerhans cells in the lentigines of four patients with the Leopard syndrome contained large membrane bound accumulations of melanin granules. Giant melanosomes were only seen in two patients. The patients had no immune-based symptoms relating to their lentigines. The Leopard Syndrome, also known as multiple lentigines syndrome, progressive cardiomyopathic lentiginosis, lentiginosis profusa syndrome and the cardiocutaneous syndrome, refers to an inherited abnormality of the skin, often associated with cardiomyopathy. The aetiology of the condition is so far unknown and the penetrance is variable. Here we describe electron microscopical findings of large accumulations of melanin within Langerhans cells.