Isolated Anterior Segment Relapse in a Child With B-Cell Precursor Acute Lymphoblastic Leukemia: A Rare Case Report.

Ocular relapse in pediatric acute lymphoblastic leukemia (ALL) is rare and typically associated with central nervous system or bone marrow involvement. Anterior segment infiltration as the sole manifestation of relapse is exceptionally uncommon and may mimic noninfectious uveitis, leading to diagnostic delay. We report the case of a 4-year-old boy with a history of B-cell precursor ALL, diagnosed at age 2 and treated according to the ALL IC BFM 2009 protocol. The patient remained in remission until presenting with persistent redness and irritation of the left eye, unresponsive to topical corticosteroids and cycloplegics. Slit-lamp examination revealed sectoral iris thickening, which was further assessed using ultrasound biomicroscopy and confirmed localized stromal infiltration without ciliary body involvement. The posterior segment was unremarkable. Initial systemic reevaluation showed no evidence of hematologic or CNS relapse, and at that time, ocular findings were provisionally considered an isolated recurrence. However, ∼3 months after the onset of ocular symptoms, the patient exhibited hematologic abnormalities, and relapse was confirmed with 31% circulating blasts, thrombocytopenia, and 92% blasts in bone marrow aspirate. He was subsequently reclassified as high-risk and systemic therapy was resumed. This case illustrates a rare presentation of anterior segment involvement as the initial manifestation of relapse in pediatric ALL. Clinicians should maintain a high index of suspicion when evaluating persistent or atypical anterior uveitis in leukemia survivors, as early recognition of ocular involvement may be critical for timely diagnosis and treatment of systemic recurrence.