Early onset acute orbital involvement in childhood acute lymphoblastic leukemia.

A 5-year-old girl with acute lymphoblastic leukemia undergoing induction chemotherapy experienced acute proptosis while agranulocytotic and febrile. Orbital biopsy showed leukemic infiltration, and complete resolution was achieved with local irradiation and chemotherapy. Early onset orbital involvement is highly unusual in acute lymphoblastic leukemia. In the setting of agranulocytosis and fever, rapidly enlarging intraorbital masses require urgent ophthalmologic attention. Immediate biopsy is indicated to distinguish between several treatable conditions including opportunistic infection, hemorrhage, and neoplastic infiltration.