Orbital presentation of Langerhans cell histiocytosis

Purpose To analyze and review an ophthalmic manifestation of an uncommon pathology such as Langerhans cell histiocytosis (LCH). Methods Single‐patient case report. Results LCH is an uncommon disorder produced by mononuclear phagocyte system cell proliferation, resulting in antigen‐presenting cells similar to Langerhans cells invading bone, skin, bone marrow, lymphatic nodes, liver, spleen and central nervous system (CNS). The number and location of affected organs is key in treatment and prognosis. In this case report, a 16‐year‐old girl presented 10 day‐long superoexternal orbital pain associated with palpebral edema, making acute dacryoadenitis and preseptal cellulitis the most common differential diagnoses. After poor response to antibiotic and anti‐inflamatory oral treatment, CT scan was ordered, showing an osteolytic frontal mass at the superoexternal orbital roof, expanding to extraconal space and anterior cranial fossa. With a differential diagnosis of LCH, osteomyelitis, hematologic disease or vascular malformation, among others, a biopsy was performed, confirming the LCH diagnosis. An extension exam was performed, excluding new tumors, reaching a diagnosis of a monostotic bone form of LCH. Chemotherapy with prednisone and visblastine was advised due CNS affectation risk because of the tumor’s location, with evident but incomplete response after six‐week induction and complete response after a second six‐week induction cycle. The patient is currently ongoing consolidation chemotherapy. Conclusions Orbital tumors are not frequent in pediatric ages, but they must be included in the differential diagnosis of orbital cellulitis, since that can be the first manifestation of these tumors.