Head and neck Langerhans cell histiocytosis: two case reports and review of the literature

Summary Langerhans cell histiocytosis (LCH) is an inflammatory neoplasia of myeloid precursor cells driven by mutations in the mitogen-activated protein kinase (MAPK) pathway. It can present as single or multisystem LCH. It occurs in 0.5–5.4 per million people. While it can occur at any age, it is more common in children, predominantly males, under the age of 4 years. The unifocal single system variety is the most prevalent and least aggressive presentation, making up to 70% of cases. It can affect bone (80%), lymph nodes (5–10%) or lungs (15%). The mandible and sphenoid are the least common locations; therefore, when present, it could be easily mistaken for a variety of pathologies. Depending on the clinical features, treatment can range from simple observation to chemotherapy and/or radiation. We present 2 cases of unifocal single system LCH located at the mandible and skull base, and describe the diagnostic work up and treatment.