Langerhans cell histiocytosis in neonates.

BACKGROUND: To study the incidence, clinical patterns, course, and outcome of neonatal Langerhans cell histiocytosis (LCH).

PROCEDURE: Retrospective analysis of the data of the Austrian/German/Swiss/Netherlands LCH Study Group. The incidence of neonatal LCH was estimated with the data from the population-based German Childhood Cancer Registry.

RESULTS: The estimated incidence of neonatal LCH (LCH diagnosed within 28 days after birth) in the population-based registry was 1-2/1,000,000. In 61/1,069 trial patients (6%), the first disease manifestations were observed in the neonatal period. However, in only 20 of them, the diagnosis was established within this period. There was a preponderance of multisystem (MS)-LCH 36/61 (59%). Cutaneous changes were the most common initial manifestation in both, single-system (SS)-LCH (92%), and MS-LCH (86%). In 72% of the MS-LCH patients, risk organs (ROs) were involved at diagnosis as well. The probability of survival at 5 years was 94% in SS-LCH and 57% in MS-LCH, which is significantly lower than in older age groups.

CONCLUSIONS: In contrast to the available literature, neonatal LCH is characterized by a clear predominance of MS-LCH. Cutaneous changes are the most common initial manifestation in neonates with both SS-LCH and MS-LCH. Prompt evaluation of disease extent upon diagnosis is mandatory for risk-adapted treatment. The disease course is unpredictable upon diagnosis. Close monitoring for disease progression is mandatory if isolated cutaneous LCH is managed by the "wait and see" approach. Neonates with MS-LCH, especially those with RO involvement at diagnosis, have less favorable prognosis compared to infants and older children, and need systemic therapy.