Systematic review of neonatal cutaneous langerhan cell histiocytosis and metaanlysis of risk of progression to systemic disease

Background: Cutaneous Langerhan Cell Histiocytosis (LCH) is a rare disorder manifest in the proliferation of cells with phenotypical characteristics of Langerhan cells. Incidence varies from 2-9 cases per million children per year. Rarely the disease is present at birth or in the neonatal period. A proportion of these cases spontaneously resolve however no consistent variables have been identified which provide predictive value as to which cases will resolve and which will manifest with systemic LCH later in infancy or childhood. Identification of clinical or histological predictive variables may reduce rates of unnecessary invasive screening in neonates with cutaneous LCH.
Methods: A systematic review was undertaken to collate all reported cases of cutaneous LCH (congenital and infantile) in the international literature. This study was registered with PROSPERO. Descriptive statistics as well as a Multivariate regression analysis was undertaken to identify any clinical or histological variables which may be associated with length of time to disease recurrence and mortality. Search strategy encompassed Pubmed, Embase, Cochrane database and all published abstracts from 1946-2016. Inclusion criteria encompassed all reports with histopathological confirmation of cutaneous LCH which occurred at birth or within the first 4 weeks of life. Case reports, case series, retrospective and prospective reviews were included, with bias analysed according to the GRADE criteria.
Results and Discussion: 155 Articles encompassing over 200 cases of cutaneous LCH were identified. We present our descriptive findings and results of our metaanlysis identifying predictive clinical and histological factors relating to progression to systemic LCH and overall mortality.

Ms Evelyn Hao