An ambispective cross-sectional descriptive study to characterise the cutaneous and histological features of pediatric Langerhans cell histiocytosis (LCH).

Background Langerhans cell histiocytosis (LCH) is an idiopathic disorder characterised by the presence of pathological Langerhans cells derived from myeloid precursor cells. There is a scarcity of data regarding its diverse cutaneous and histological presentations, as well as their prognostic implications. Objectives To investigate the clinical and histological features in children with LCH and explore the correlation between the frequency and severity of systemic involvement and various clinical and histopathological findings. Methods A two-year ambispective cross-sectional descriptive study was conducted at a tertiary referral centre to identify and describe the clinical and histological features of LCH. Twenty patients (10 prospective and 10 retrospective) were diagnosed based on histopathology. Results This study included 20 patients with LCH, majority in the age range of 1-5 years and with male predominance (75%). The primary complaint was fever (100%), accompanied by itching (65%), abdominal pain (45%), or respiratory issues (40%). Scalp involvement was universal, with erythematous papules (95%) being the most common type of lesions. Systemic examination revealed hepatomegaly (65%), splenomegaly (40%), and cervical lymphadenopathy (50%). Histopathological evaluation from varied skin lesions revealed dense dermal infiltrates of Langerhans cells, with papillary dermal oedema and significant RBC extravasation. Immunohistochemistry confirmed Langerhans cells. Systemic evaluation indicated organ involvement in varying percentages. Limitations Small sample size and retrospective nature of half of the cases are major limitations of our study. Conclusion This study shows skin lesions may develop as crops and fever is a consistent feature found on history or at presentation which may act as important clues towards clinical diagnosis of LCH. In terms of histological features, papillary dermal oedema and RBC extravasation are some prominent findings. Histopathological features does not predict the progression of disease and the extent of systemic involvement.