The multiple faces of Langerhans cell histiocytosis in childhood: A gentle reminder

Abstract

Langerhans cell histiocytosis (LCH) is a rare hematologic disorder that results from the clonal multiplication and accumulation of immature dendritic Langerhans cells. Its reported incidence rate varies, but is considered to be 2.6-8.9 per million children who are <15 years of age each year. It may affect any system or organ. The present study reported 4 pediatric LCH cases in order to highlight the heterogeneity of the initial presentation, and the pitfalls that may mislead clinicians and delay diagnosis. The clinical features, as well as the pathognomonic imaging, pathology findings and treatment options were presented. LCH may be rare, but it should always be included in the differential diagnosis of persistent eczema, unexplained skin lesions, diabetes insipidus and persistent bone pain, among others. While the debate on pathogenesis and treatment is ongoing, high index of suspicion among pediatricians, pediatric oncologists and other specialists (pathologists, dermatologists, orthopaedic surgeons, general practitioners or family physicians) is essential for early diagnosis, and optimal outcome.

Keywords: Langerhans cell histiocytosis; bone pain; children; diabetes insipidus; lytic lesion; rash.

Figure 1.

A 5-month old female LCH patient with persistent rash on the trunk since birth, (A) before and (B) after the first cycle of chemotherapy (prednisolone + vinblastine).

Figure 2.

Initial imaging/pathology findings of all patients. (A) Patient no. 1: 3D-CT scan of the skull illustrating lytic lesion of the frontal bone. (B) Patient no. 2: CT scan of the pelvis illustrating lytic lesion of the left iliac bone. (C) Patient no. 3: Skin biopsy sample positive staining for protein S-100 (×200). (D) Patient no. 4: Plain film of the femur imaging lytic lesion of the left femur.