A 3-year-old female patient was presented to Ain Shams University Pediatric Hospital (Egypt) with persistent frontal headache. There were no localizing symptoms and virology studies were negative. The child's visual acuity decreased gradually. After extensive medical workup to exclude the common causes of childhood headaches, the patient was diagnosed with acute lymphoblastic leukemia (ALL) depending on the flowcytometric analysis of the Cerebrospinal fluid (CSF) sample; as the blast cell count in both complete blood count (CBC) and bone marrow (BM) samples were < 20% being decreased due to corticosteroid therapy patient already received initially in an attempt to lower her intracranial tension before her definite diagnosis. The patient received induction, consolidation chemotherapy, and central nervous system (CNS) treatment with intrathecal methotrexate and cranial irradiation. She developed ALL relapse after her first remission, she presented with intracranial hypertension and optic nerve infiltration by leukemic cells followed by systemic relapse. Subsequent surgical intervention, salvage chemoradiotherapy, and further allogeneic stem cell transplantation did not induce disease remission or restore her visual acuity. The delayed initial diagnosis due to the atypical initial presentation of the case, was associated with poor outcome, and the patient died almost one year after her initial diagnosis.