Myelodysplasia From Valproic Acid Resolved by Cessation

Area of Science:

• Hematology
• Pharmacology
• Oncology

Background:

• Myelodysplastic neoplasms (MDS) are clonal blood disorders characterized by ineffective hematopoiesis and risk of acute myeloid leukemia.
• While chemotherapy and radiation are common causes, certain medications like valproic acid (VPA) can induce reversible myelodysplastic features.

Purpose of the Study:

• To report a case of valproic acid-induced myelodysplasia.
• To emphasize the importance of recognizing drug-induced myelodysplasia as a mimic of primary MDS.

Main Methods:

• A middle-aged woman with complex comorbidities presented with pancytopenia and weight loss.
• She had been on VPA for over a year, with recent dose escalation.
• Peripheral smear and bone marrow biopsy were performed; VPA was discontinued and switched to lacosamide.

Main Results:

• The patient presented with pancytopenia, pseudo-Pelger-Huët cells, and thrombocytopenia.
• Bone marrow showed hypocellularity, erythroid hyperplasia, and megakaryocytic dysplasia.
• Blood counts improved within a week of VPA cessation and normalized completely over weeks.

Conclusions:

• Valproic acid-induced myelodysplasia is a reversible condition that can mimic primary MDS.
• VPA's histone deacetylase (HDAC) inhibitor activity may contribute to its hematologic toxicity.
• Clinicians should consider VPA-induced myelodysplasia in patients with unexplained cytopenias on long-term VPA therapy.