Adult-onset Langerhans cell histiocytosis - A Trojan horse of oral cavity: A case report with rare clinical presentation.

Langerhans cell histiocytosis (LCH), earlier recognised as histiocytosis X, is a rare haematological illness involving infants and young children. LCH is caused by unrestrained stimulation and proliferation of usual antigen presenting cells, Langerhans cells (LCs) and the disease demonstrates extensive clinical and radiographic features involving multiple sites. Since the incidence is relatively low limited data is available regarding the epidemiology of LCH, with approximation of 2-5 cases per million populations per year. LCH has male predilection with jaws involved in 10-20% cases and only 1% of the cases affecting maxilla, masquerading as periodontal or periapical pathology. We report a case of 48-year-old female with LCH involving posterior maxilla. This is a unique presentation corresponding to age, gender, location and severity. Dental clinicians should be aware of this and consider it to be a part of their differential diagnosis pertaining to unresolved periodontal pathology as it mimics clinically and radiographically.