Isolated eyelid neonatal Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a condition characterized by clonal proliferation of the phagocytic cells derived from the bone marrow. In this article, we present an exceedingly rare case of congenital/neonatal LCH in a 3-week-old girl who initially presented with an isolated swelling of the eyelid, initially misdiagnosed as a chalazion. Subsequently, a biopsy was performed, and histopathological evaluation confirmed the diagnosis of LCH. A staging work-up revealed no evidence of multisystem involvement, and thus, local steroid injection was performed as the initial treatment for the residual lesion. Cases of localized LCH that manifest as eyelid masses are rare, and most reported cases involve children over the age of one year. To the best of our knowledge, this case represents the first reported instance of neonatal LCH presenting as an eyelid mass. Although neonatal LCH is rare, ophthalmologists must be aware of this presentation and include it in the differential diagnosis for eyelid lesions in infants during the first month of life.