ID #670 A Rare and Severe Complication: Aplastic Anemia After a Single Cycle of Temozolomide in a Child with Recurrent Ependymoma

Background

Temozolomide is an alkylating chemotherapeutic agent commonly used in the management of high-grade central nervous system (CNS) tumors. While myelotoxicity, most commonly manifesting as thrombocytopenia, is a recognized adverse effect, profound myelosuppression in otherwise chemotherapy-naïve patients is rare. Severe aplastic anemia represents an even more uncommon complication of temozolomide therapy, occurring in fewer than 1% of treated patients, reported predominantly in adults (mean age 60.7 years) and associated with substantial morbidity and mortality.

Case/Methods

A 12-year-old female experienced relapse of PF-A ependymoma approximately two years after initial treatment with gross total resection and focal radiation. At recurrence, only near-total resection was feasible. Given the proximity to prior radiation and location of residual disease, repeat radiation was deemed unsafe. The patient was therefore initiated on oral temozolomide at a standard dose for high-grade CNS tumors (200 mg/m² daily for 5 days). Following a single cycle of therapy, she developed a delayed hypersensitivity reaction characterized by urticaria and emesis three days after completion, which resolved with epinephrine and corticosteroids. Approximately 3.5 weeks after temozolomide administration, she presented with profound pancytopenia, manifesting as acute-onset wet purpura and active mucosal bleeding. Due to the severity of cytopenias and minimal response to transfusion support, a bone marrow biopsy was performed, demonstrating marked aplasia with <5% overall cellularity, nearly absent granulopoiesis and megakaryopoiesis, and markedly decreased erythropoiesis. The patient was treated with prophylactic antibiotics, granulocyte colony-stimulating factor, and romiplostim, resulting in partial hematologic recovery within four weeks.

Conclusion

Severe aplastic anemia represents a rare but potentially fatal complication of temozolomide therapy in patients with CNS malignancies. To our knowledge, this represents the youngest reported case of temozolomide-induced aplastic anemia, underscoring that this complication can occur in children and highlighting the importance of early recognition and proactive hematologic surveillance, even after a single cycle of treatment.

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