Abstract
Objective: To report pancytopenia caused by temozolomide, a second-generation alkylating agent. Clinical Presentation and Intervention: A 22-year-old patient presenting with seizures and confusion was seen in the emergency room. Cranial magnetic resonance imaging revealed a mass. After surgery, the patient was diagnosed with glioblastoma multiforme and was given temozolomide at 150 mg/m2 on days 1 through 5 every 4 weeks. During the last cycle of temozolomide, grade 3 thrombocytopenia persisted. Possible causes of pancytopenia including vitamin B12 deficiency were investigated. Conclusion: This case report shows that vitamin B12 deficiency can be a potential cause of pancytopenia and it should be kept in mind for patients receiving chemotherapy.