Hypothalamic-pituitary abnormalities in paediatric histiocytosis: preliminary retrospective data from a large cohort of a tertiary italian center

Francesco Pezzoli; Eugenio Trinati; Maddalena Bagni; Coniglio Maria Luisa; Irene Trambusti; Franco Ricci; Stefano Stagi; Elena Sieni

doi:10.1530/endoabs.110.P899

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Endocrine Abstracts (2025) 110 P899 | DOI: 10.1530/endoabs.110.P899

ECEESPE2025 Poster Presentations Pituitary, Neuroendocrinology and Puberty (162 abstracts)

Hypothalamic-pituitary abnormalities in paediatric histiocytosis: preliminary retrospective data from a large cohort of a tertiary italian center

Francesco Pezzoli ^1,2 , Eugenio Trinati ^1,3 , Maddalena Bagni ¹ , Maria Luisa Coniglio ² , Irene Trambusti ² , Franco Ricci ³ , Stefano Stagi ^1,3 & Elena Sieni ²

Author affiliations

¹Department of Health Sciences, University of Florence, Florence, Italy; ²Department of Pediatric Hematology Oncology, Meyer Children’s Hospital IRCCS, Florence, Italy; ³Diabetology and Endocrinology Unit, Meyer Children’s Hospital IRCCS, Florence, Italy

JOINT2241

Introduction: Histiocytosis is a rare hematologic condition involving tissue infiltration by dendritic cells, macrophages, or monocytes. Langerhans cell histiocytosis (LCH) has an estimated incidence of 2–9 cases per million children annually. Pituitary involvement, particularly diabetes insipidus (DI), affects 5–30% of cases, potentially leading to multiple pituitary hormone deficiencies (MPHD).

Patients and Methods: This retrospective study analysed 115 paediatric histiocytosis cases diagnosed from September 2004 to September 2024 at the Italian Referral Center for Histiocytosis in Florence, Italy. The median age at diagnosis was 7 years (IQR 10). Demographic, clinical and biological data were collected.

Results: The cohort included a total of 115 patients: 105 LCH, 3 Juvenile Xanthogranuloma, 3 mixed forms, 2 Rosai-Dorfman, 1 histiocytic sarcoma, and 1 indeterminate cell histiocytosis. A total of 36/115 (31%) patients had pituitary functional involvement: 33 LCH and 3 mixed forms. DI was diagnosed in 34/115 (29.5%) patients at a median age of 5,7 (IQR 3). It was the first manifestation in 17/34 (50%) and developed after a median of 4 years (IQR 3.25) in remaining cases. Growth hormone deficiency (GHD) was the second most common hormonal deficiency, affecting 11/115 (9.6%) patients, with an average onset of 8.6 years (IQR 4). In 1/11 (9%) cases, GHD was isolated; in 10/11 (91%) cases, it was associated with DI. Of these, 2/10 (20%) had GHD at disease onset, and 8/10 (80%) developed it after a median of 4.8 years (IQR 3.25) following DI onset. Central hypothyroidism occurred in 4/115 (3.5%) patients, all with DI. Hypogonadotropic hypogonadism affected 4/115 (3.5%), all with DI and one with hyperprolactinemia. Precocious puberty was observed in 1/115 (0.8%) male patient. Central adrenal insufficiency developed in 2/115 (1.7%), both with DI and GHD. MPHD occurred in 12/34 (35.2%) DI patients.

Conclusions: To the best of our knowledge, this represents one of the largest paediatric cohorts of endocrinopathies in histiocytosis. Hypothalamic-pituitary hormone deficiencies may be the first manifestation of histiocytosis or may complicate it during the course of disease. Thus, paediatric endocrinologists should screen and monitor these patients in close collaboration with hematologist-oncologist with expertise in histiocytosis.