Langerhans cell histiocytosis
Pronunciation: LANG-er-hanz sel his-tee-oh-sy-TOH-sis
Also written as: LCH — Langerhans cell histiocytosis
A clonal proliferative disorder of Langerhans cells presenting with variable cutaneous, bony, and systemic involvement, often first identified via skin lesions in infants.
Full Definition
Langerhans cell histiocytosis (LCH) is a neoplastic proliferation of CD1a+/CD207+ (langerin+) Langerhans cells driven in most cases by the BRAF V600E mutation. In pediatric patients, cutaneous findings—including seborrhoeic-like scalp crusting, petechial or purpuric papules in flexural areas, and erosive skin lesions—frequently precede systemic diagnosis. LCH spans a spectrum from single-system disease (e.g., isolated bone lesion) to multisystem disease with high-risk organ involvement. Editors must capitalise both eponyms ('Langerhans' and the abbreviation 'LCH') and should not shorten to 'histiocytosis' without disambiguation.
Usage
Usage note: The older term 'histiocytosis X' is obsolete and should not be used in current editorial contexts. Capitalise 'Langerhans' as an eponym throughout.
In Context
- "Skin biopsy of the scalp crust revealed CD1a-positive cells, confirming Langerhans cell histiocytosis in this four-month-old infant." — Pediatric haematology–oncology case note
- "The manuscript should consistently use 'Langerhans cell histiocytosis' rather than the outdated term 'histiocytosis X.'" — Journal manuscript editorial comment