An Epidural Mass in B-cell Precursor Acute Lymphoblastic Leukemia at Diagnosis.

We report the case of an 8-year-old girl with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), who presented with a symptomatic epidural mass at the initial diagnosis. She had persistent back pain and mild neurological symptoms. Magnetic resonance imaging (MRI) revealed an epidural mass extending from L2 to the sacrum without spinal cord compression. A bone marrow examination confirmed BCP-ALL. A biopsy was deferred because of procedural risks, and systemic chemotherapy combined with corticosteroids was initiated. Her symptoms resolved rapidly, and follow-up MRI showed a marked regression of the mass. In selected patients without severe neurological deficits, careful observation after chemotherapy initiation may precede invasive diagnostic procedures.