Pediatric pulmonary multisystem langerhans cell histiocytosis: does lung lesion severity affect the outcome?

Abstract Background The pediatric pulmonary multisystem Langerhans cell histiocytosis (PPM LCH) is associated with either low risk or high risk organ(s). The nodulo-cystic lung lesions although pathognomonic, yet are very variable in severity and remain a source of controversy in certifying pulmonary LCH diagnosis. The study aimed to examine the prognostic value of clinical respiratory manifestations and radiological lung lesions severity. This is through associating a CT chest triad of bilateral, extensive and diffuse lesions. It is a retrospective study of 350 LCH patients who received systemic treatment at Children’s Cancer Hospital Egypt during the period from 2007 to 2020. Results Sixty-seven patients (67/350–19.1%) had PPM LCH at presentation. Severe lung lesions were present in 24 of them. The median follow-up period was 61 months (IQR: 3.4–8.3). The 5-year overall survival (OS) and event free survival (EFS) was 89% and 56.6% respectively. The EFS, for severe radiological lesions triad was 38% ± 20.7 versus 66% ± 16.2 for non-severe lesions triad p 0.002, while for presence of chest X-ray changes 27% ± 22.344 versus absence of chest X ray changes 66% ± 14.7 p 0.001, for clinical respiratory manifestations 13% ± 13.9 versus none 62% ± 22.9 p