Acute basophilic leukemia in a child. Anaphylactoid reaction and coagulopathy secondary to vincristine-mediated degranulation.

BACKGROUND: Acute de novo basophilic leukemia (ABL) is uncommon in adults, and extremely rare in children. To the authors' knowledge, there have been no previous reports of anaphylactoid reactions from basophilic degranulation in children with this condition.
METHODS: This report describes the clinicopathologic profile and complications of a patient with de novo ABL.
RESULTS: Immediately after the first induction dose of intravenous vincristine, the patient developed an anaphylactoid reaction and disseminated intravascular coagulation with massive pulmonary hemorrhage. A normal serum tryptase level suggested that this life-threatening event was secondary to tumor lysis (basophilic degranulation), rather than to a mast-cell mediated anaphylactic reaction to vincristine. This interpretation is supported by the coagulation studies, which suggested release of heparin from the blast granules.
CONCLUSIONS: Although de novo ABL is rare, it should be considered when cytoplasmic basophilic granules are seen in the leukemic cells of patients with what otherwise appears to be undifferentiated leukemia, and the pertinent diagnostic procedures should be undertaken. During the treatment of ABL, potential complications related to basophilic degranulation should be anticipated, and antihistamine prophylaxis may be of value.