Langerhans' cell histiocytosis: a clinicopathological study of 50 cases.

To analyze the clinicopathologic features and outcome of patients with Langerhans cell histiocytosis (LCH). Fifty cases of LCH accrued over a 15-year period were analyzed and classified as having unifocal, multifocal, or multisystem disease. Events regarding progression, relapse, or death were noted. The 50 cases comprised of 34 men and 16 women. 92% of the patients were less than 15 years of age and 46% were less than 2 years. Involvement by LCH was unifocal in 22, multifocal in 8, and multisystem in 20. Bone was the commonest site (92%), followed by lymph node (30%). The histological features were relatively uniform regardless of the clinical severity, and consisted of Langerhans cells, eosinophils, histiocytes, plasma cells, giant cells and fibrosis. The treatment consisted of surgery, chemotherapy, and/or radiotherapy. Response to treatment was poor in patients with multisystem disease. The histology of LCH is very characteristic and patients with age less than 2 years are more likely to have increased risk or morbidity and mortality, due to widespread disease.