Late effects of langerhans cell histiocytosis and the association of LCH with malignancy

Abstract

The term permanent consequences is often used to describe the portfolio of possible late complications occurring in patients with LCH. Consequences may be already evident at the moment of LCH diagnosis or become manifest even more than 10 years after the end of therapy. They may be due either to the site of the original disease or to age at treatment and type and doses of treatments received. Since the bony skeleton is the most common site of involvement of LCH, the commonest sequelae tend to be orthopaedic and include pathological fractures, malformation, scoliosis and vertebra plana Diabetes insipidus is the most reported endocrine abnormality, and patients with multisystem disease and involvement of the craniofacial bones are those at higher risk. Other abnormalities may affect anterior pituitary with growth hormone deficit being the most frequent. Neurological problems such as cerebellar ataxia, psychological problems and learning difficulties can occur, with impact on school performance and quality of life. Hearing loss and pulmonary problems are other common possible late complications. Possible other side effects should also be carefully monitored in patients treated with novel targeted therapies involving BRAF/MAPK pathways. LCH may be associated with other malignancies occurring either before, concurrently or after LCH diagnosis. In general ALL usually precedes LCH, while AnLL and solid tumours develop after LCH. Long-term and patient-oriented follow-up in children with LCH is recommended.