Acute lymphoblastic leukemia following temozolomide treatment in a patient with glioblastoma: A case report and review of the literature.

Temozolomide (TMZ) is a second-generation oral alkylating agent that functions against a number of central nervous system neoplasms, and is generally used to treat high-grade gliomas, including anaplastic astrocytoma and glioblastoma multiforme. Therapy-related secondary myelodysplastic syndrome and acute myeloid leukemia have been reported in patients following prolonged exposure to TMZ. However, TMZ-related acute lymphoblastic leukemia (ALL) is extremely rare. The present study describes the case of an 11-year-old boy with a 3-day history of generalized tonic-clonic seizures and a contrast-enhanced lesion in the left temporooccipital region with focal cystic degeneration, as detected by magnetic resonance imaging. The patient underwent craniotomy and gross-total resection andpathological analysis confirmed the diagnosis of giant cell glioblastoma. Postoperatively, the patient received TMZ-based concurrent chemoradiation during radiotherapy, and developed B-cell ALL 6 months following TMZ treatment. A thorough literature search identified only six published cases of TMZ-related ALL. The chemotherapeutic efficacy of TMZ has been identified, however, its leukemogenic potential should be emphasized among practitioners and patients. Further studies are required to determine the specific pathogenic mechanism of TMZ-related ALL. Close hematological monitoring of patients following TMZ treatment is vital and a high index of suspicion is necessary.