Isolated Unilateral Optic Nerve Involvement as the Presenting Feature of Early Relapse in Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia

Central Mervous System involvement (CNS) in Acute Lymphoblastic Leukemia (ALL) can be present at initial diagnosis or at disease relapse and early detection is crucial for prompt intervention. Optic nerve infiltration by leukemic cells is an oncologic emergency that requires urgent therapy to spare vision along with systemic therapy, with limited data about the optimal therapeutic strategy. Isolated optic nerve Involvement at relapse is rare; described in Philadelphia chromosome negative (Ph-) ALL in 2.2% of relapses in children and exceeding rare in Philadelphia chromosome positive (Ph+) cases, particularly in the absence of systemic disease. Here we report isolated unilateral optic nerve involvement as the sole feature of early disease relapse in Ph+ ALL in the absence of systemic disease, leading to early detection of molecular relapse.