Sandbox: Langerhans

LCH is a rare disease, affecting approximately 5 to 6 persons per 1 million people annually in the United States It is primarily encountered in pediatric patients; 50% to 90% of cases are diagnosed between the ages of 1 year and 15 years.

• Langerhans cell histiocytosis commonly affects individuals younger than 15 years of age.
• The median age at diagnosis is depends on the specific subtype of the disease, such as:

• Pulmonary Langerhans cell histiocytosis is usually first diagnosed among adults.
• Unifocal Langerhans cell histiocytosis and multifocal unisystem Langerhans cell histiocytosis are usually first diagnosed among individuals of 2-10 years of age.
• Multifocal multisystem Langerhans cell histiocytosis is usually first diagnosed among individuals younger than 2 years of age.

Patients with isolated EG bone lesions typically present at age 5 to 15 years, whereas those with systemic forms of LCH present earlier (age 1 year to 5 years). These lesions predominantly affect males, with a male-to-female ratio of 2 to 3:1 reported.