Alemtuzumab-based therapy for Secondary Malignant Histiocytosis arising from Pre-B-ALL.

•Secondary Malignant Histiocytosis (SMH) is an exceedingly rare, life-threatening condition that invariably occurs in the presence of an underlying monoclonal hematologic disorder. Prognosis of SMH remains dismal and there is no established treatment. •We report a case of a patient who developed SMH during induction chemotherapy for his underlying pre-B-ALL, that caused persistently high fevers and was only diagnosed by a marrow while cytopenic in phase 2 induction.