Hypercalcemia in Langerhans cell histiocytosis: is it therapy-related?

Hypercalcemia is not known to be a common occurrence in patients with Langerhans cell histiocytosis (LCH). This manuscript describes an infant with multisystem LCH who developed an elevated serum calcium level while on therapy. Unlike other cases of hypercalcemia, this patient did not have evidence of bone involvement. Based on the apparent rarity of the condition and the clinical presentation, it is likely that hypercalcemia in LCH is a multifactorial process. The author presents evidence supporting the hypothesis that the treatment regimen is a major factor in the etiology of this metabolic abnormality and suggests that calcium levels be routinely measured during therapy.