Unilateral Cytomegalovirus Retinitis in a Child With Acute Lymphoblastic Leukemia While on Maintenance Chemotherapy.

Cytomegalovirus retinitis (CMVR) commonly affects immunocompromised individuals, including acquired immunodeficiency syndrome (AIDS), post-organ transplant recipients and allogeneic stem cell transplant recipients. CMVR occurring in the acute lymphoblastic leukemia (ALL) maintenance phase of chemotherapy is rare and has been described in the literature as isolated case reports or case series. We report a case of unilateral CMVR in a pediatric patient during maintenance phase therapy for ALL. A 14-year-old boy known case of T-cell ALL with CNS2a status, was treated according to the Children's Oncology Group (COG) AALL0434 protocol. Induction therapy consisted of the standard high-risk four drugs, in addition to intrathecal methotrexate. At week 166 of maintenance therapy, the child presented with painless progressive loss of vision in the right eye for one week. The best-corrected visual acuity (BCVA) of the right eye was 6/36 and the left eye was 6/6. Dilated fundus examination of the right eye showed multiple large yellow-white cloudy chorioretinal lesions with areas of intraretinal hemorrhages in the macula, and overlaying focal vitritis. Optical coherence tomography (OCT) of the right eye showed macular edema and mild subretinal fluid. Cytomegalovirus polymerase chain reaction of the blood was detected with high quantitative value. A diagnosis of CMVR was made and an induction doses of intravenous ganciclovir was followed by maintenance doses of oral valganciclovir. Our case suggests that pediatric patients with ALL in the maintenance phase are considered immunocompromised and that physicians should be aware of CMVR incidence in such group. Early diagnosis and prompt treatment are important to preserve vision and prevent future visual morbidity.