Erdheim Chester Disease with Calvarial Involvement: A rare case of Histiocytosis.

Erdheim-Chester Disease is a rare systemic xanthogranulomatous infiltrating disease, characterized by lipid-laden histiocytes accumulating in various organs and almost always in bones. Etiology of the disease is still unknown. It may involve various organs and systems, such as musculoskeletal, cardiac, pulmonary, renal, gastrointestinal and central nervous system (CNS) as well as the skin. The most common systemic manifestations are bone lesions and the specific sign of these are bilateral sclerosis of the diaphysis and metaphysis of long bones. Symptoms and signs can vary related to the organ or system that is involved. In CNS involvement, cerebellar and pyramidal symptoms and signs are the most common, while headache, seizure, cranial nerve paralysis, neuropsychiatric along with cognitive complaints and mood disorders are also reported. Furthermore, there are asymptomatic cases. Histologically lipid-laden foamy histiocytes with small round nucleuses and without nuclear grooves are the characteristic histological features. These histiocytes show positive CD68 and negative S100 and CD1a immunoreaction. Surgery is a reasonable treatment in the patients who have extra- or intracranial lesions with smooth borders when the neurological signs and symptoms are mild. Medical treatment of the disease includes steroid, cytotoxic agents such as cladribin, IFN α-2a, recombinant human interleukin-1 receptor antagonist, tirosine kinase inhibitors, biphosphonate and autologue hematopoetic stem cell transplantation. In this report a 29 years old man was presented with a frontal calvarial lesion who was operated and diagnosed as Erdheim Chester disease.