Langerhans cell histiocytosis has long been described as a rare systemic disorder involving the proliferation of Langerhans cells with formation of granuloma. The disease may be localised or diffuse. Typical forms of the disease involving the bone, the skin or the pituitary gland have been well described whereas others, such as thymic histiocytosis, are still poorly understood. Here, we report a case of isolated Langerhans cell histiocytosis of the thymus in an infant with nonspecific symptoms. We provide a description of the disease and discuss patient management.