Clinical Profile and Treatment Outcomes of Adult Non-Pulmonary Langerhans Cell Histiocytosis from a Tertiary Care Hospital in South India.

UNLABELLED: Langerhans Cell Histiocytosis (LCH) is a haematological malignancy characterized by the clonal Langerhans cells proliferation. There is paucity of data on adult patients with LCH in India. We reviewed 18 patients of Adult Non-Pulmonary LCH treated at our institute from 2019 to 2024. Their Clinico-pathological features, treatment given and survival were studied. Median age at diagnosis was 30 years. 61% were males. 61% patients presented with bone lesions and 50% with lymphadenopathy. Immuno-Histochemistry (IHC) for CD1a, S100 were positive in all cases. 20% of the tested patients were positive for BRAF V600E mutation. 61% cases were multisystem LCH. Diabetes insipidus was seen in 4 patients (22%). 2 patients underwent curettage of the bone, 1 received radical Radiation therapy. 15 received systemic treatment: 9 received Vinblastine-prednisolone (LCH-3 Protocol) and 6 received cytarabine. Overall response rate was 78%. Median progression free survival was 34 months and median overall survival not reached after a median follow up of 42 months. This study adds to the few case reports of Adult LCH among Indian patients and helps in better understanding of their presentation and responses to therapy. Cytarabine and LCH 3 protocol show good long-term survival in Indian patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s12288-025-02278-3.