Primary musculoskeletal Langerhans cell histiocytosis in children: an analysis for a 3-decade period.
BACKGROUND
Langerhans cell histiocytosis (LCH) is a rare group of disorders of unknown etiology with a wide spectrum of clinical presentation. We sought to identify what, if any, has changed in the past 3 decades. This review outlines the current concepts in etiology and molecular biology, clinical manifestations, imaging features, treatment guidelines, and outcomes for skeletal LCH.


METHODS
A database of LCH cases diagnosed at a tertiary referral center during a 3-decade period was retrospectively reviewed to identify children with primary bone involvement. All patients' charts and available imaging examinations were reviewed, and the data collected included sex, age, number and location of the musculoskeletal lesions, presence of extraskeletal lesions and/or systemic disease, presence of clinical symptoms, treatment (medical and/or surgical), complications, and outcomes.


RESULTS
Seventy-nine children met the inclusion criteria. Forty-five (57%) of the 79 children had single-bone disease, with a mean age at presentation of 8.9 years, whereas 34 (43%) of the 79 children presented with multiple skeletal lesions (range, 2-7 lesions) at a mean age of 7.4 years. There were 165 skeletal lesions in the 79 patients (mean, 2 lesions per patient). The most common presenting symptom was pain at the lesion site (63 patients, 79%). On imaging, the lesion usually presented as a well-defined, radiolucent lesion located within the diaphysis or metaphysis. Among children with single-bone involvement, 11 underwent observation and symptomatic treatment, 17 had biopsy followed by observation and symptomatic treatment, and 17 had biopsy followed by excision. Eight children also received chemotherapy, and 2 had radiation (early in the series). Among children with multiple-bone disease, 10 underwent biopsy followed by symptomatic treatment, 24 underwent biopsy, followed by chemotherapy, and 3 also received radiation (early in the series).


CONCLUSIONS
There is variability of presentation in musculoskeletal LCH. Biopsy is usually indicated for diagnostic confirmation. Although the natural history for most lesions is of gradual healing, curettage and grafting are sometimes indicated to accelerate the healing process. Internal fixation for stability is occasionally necessary. Chemotherapy is used for multisystemic disease, and radiotherapy is no longer used.
Keck School of Medicine, Children's Orthopaedic Center, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA, USA.
Alexandre
A
Arkader
Michael
M
Glotzbecker
Harish S
HS
Hosalkar
John P
JP
Dormans
D000293:Adolescent; D017677:Age Distribution; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D018483:Diaphyses / Q000473:pathology; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010146:Pain / Q000209:etiology*; D059408:Pain Management; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult