Facial diplegia as the presenting manifestation of acute lymphoblastic leukemia

A 36-year-old man with recent onset of unilateral peripheral 7th nerve pare -sis presented ten days later with involvement of the other side of his fac e. Physical examination was otherwise normal, and since blood tests and ima ging were also normal, he was considered to have bilateral Bell's palsy. Ho wever, unexpected headaches and worsening of the paresis led to a gallium-6 7 scan which revealed uptake in the mediastinum. A repeat lumbar puncture r evealed cells which were identified as lymphoblasts. T-cell acute lymphobla stic leukemia (T-ALL) was diagnosed, although the peripheral blood smear wa s normal. The differential diagnosis of bilateral 7th nerve palsy and of mo nonuclear cerebrospinal fluid pleocytosis is discussed, as well as this rar e central nervous system presentation of acute leukemia.