Bilateral facial palsy as presenting symptom of post-transplant relapsed acute myeloid leukemia treated with venetoclax: a case report and literature review.

Extramedullary relapse (EMR) of acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (HSCT) is rare and challenging condition, associated with poor outcomes, especially in children. We describe a 5-year-old boy with therapy-related AML who developed bilateral facial palsy as the first sign of EMR, eight months after HSCT. Initial investigations, including bone marrow (BM), cerebrospinal fluid (CSF), and MRI, were inconclusive. Progressive symptoms and rising of minimal residual disease prompted repeated evaluations and, ultimately, led to the diagnosis of a bilateral extramedullary leukemic infiltration. The patient was treated with venetoclax combined with high-dose cytarabine and idarubicin, achieving complete resolution of the EMR and also first-ever molecular remission of the disease, further consolidated with a second HSCT. This case underscores the diagnostic challenges of EMR presenting with neurologic symptoms and supports the feasibility and efficacy of venetoclax-based intensive chemotherapy for EMR, even after prior HSCT, in pediatric AML patients.