For a study, researchers sought to determine the characteristics and treatment results of children with Pediatric Langerhans cell histiocytosis (LCH) with thymic involvement. Between September 2016 and December 2019, they retrospectively reported the clinical, biochemical, and imaging aspects of 19 patients with juvenile LCH with thymic involvement at the facility. They also looked at the treatment responsiveness and outcomes of chemotherapy or targeted therapy patients.
Thymic involvement was detected in 4.4% of a 433-person juvenile LCH cohort; all LCH–thymic involvement patients had a multisystem illness. Patients with thymic involvement were usually younger, with more significant lung, thyroid, and bone involvement than those without thymic involvement. Most patients with thymic involvement experienced immunocompetence changes, including lower numbers of T-lymphocyte subsets and immunoglobulin G levels. Overall, 47.1% of patients responded to induction therapy after 6 weeks, while 92.3% of patients who did not react to first-line treatment achieved complete remission with second-line and/or targeted therapy. There was no difference in progression/relapse rates between patients who received second-line treatment and those who received dabrafenib (33.3% vs. 25%, P=1.000). Patients with thymic involvement had the same survival rate as those without thymic involvement. However, second-line chemotherapy patients experienced more serious adverse events than those receiving dabrafenib (88.9% vs. 0%, P<.001).
Thymic involvement was rare in LCH and had distinct clinical features. Therefore, most thymic lesions might be resolved with chemotherapy, and BRAF inhibitors could be a viable treatment option with reduced toxicity for newborns with the BRAF-V600E mutation.
Reference:www.jpeds.com/article/S0022-3476(22)00008-7/fulltext
