Letter to the Editor

Abstract

We read with great interest the article by Alexander and Zacharin¹. Their comprehensive analysis of the endocrine manifestations of Langerhans cell histiocytosis (LCH), highlighting central diabetes insipidus (CDI) as the most common endocrine disorder in these patients, provides valuable insights into the long-term sequelae of this rare condition. We would like to offer additional perspectives based on recent literature and our own clinical experience.

The findings by Alexander and Zacharin align with earlier reports, where CDI has been frequently identified as an initial manifestation of LCH.^{2, 3} In our own retrospective study at Taipei Veterans General Hospital, CDI was observed in 21.4% of paediatric LCH patients, consistent with the 15% reported by Alexander and Zacharin.⁴ The presence of CDI often precedes other systemic manifestations of LCH, highlighting its potential as a critical marker for early diagnosis and intervention. Marchand et al.⁵ found that in 26 children with LCH, isolated CDI was the initial presentation, often occurring months or even years before other LCH symptoms. This underscores the importance of long-term vigilance and follow-up in patients presenting with isolated CDI.

Alexander and Zacharin emphasise the need for ongoing pituitary assessment to detect evolving deficiencies, a point we strongly support, particularly concerning growth hormone deficiency (GHD). Their study reports a 7% incidence of GHD, while other studies have shown higher rates, ranging from 13% to 20%.^{6, 7} These variations may stem from differences in follow-up duration or assessment methodologies, highlighting the need for standardised long-term endocrine monitoring protocols in LCH patients.

We would also like to highlight the potential role of novel therapies, such as BRAF and MEK inhibitors, in managing LCH and its endocrine complications. Cournoyer et al.⁸ have shown promising results with these targeted therapies in treating refractory or relapsed LCH. While primarily aimed at controlling disease progression, their impact on endocrine outcomes, particularly in preventing or ameliorating pituitary dysfunction, deserves further exploration.

Our experience managing LCH at Taipei Veterans General Hospital has underscored the importance of interdisciplinary collaboration in the long-term care of these patients. Close cooperation between endocrinologists, oncologists and primary care providers is crucial to ensure comprehensive management, even after patients are discharged from tertiary care. As seen in our cohort, 35.7% of patients entered a chronic phase of the disease, necessitating ongoing monitoring and intervention.⁴

In conclusion, the study by Alexander and Zacharin significantly contributes to understanding the endocrine aspects of paediatric LCH. Future research should focus on prospective studies incorporating standardised endocrine assessments and investigating the impact of novel therapies on endocrine outcomes. Such efforts will be essential in advancing the care of children with this complex disorder.