Facial Nerve Palsy in a Young Patient With Acute Lymphoblastic Leukemia Possibly Induced by Herpes Virus Reactivation in the Facial Nerve.

Facial palsy in acute lymphoblastic leukemia (ALL) patients is diagnosed as tumor cell invasion of the central nervous system (CNS) following the ALL guidelines. Facial palsy in a 6-year-old ALL patient was diagnosed as leukemia cell invasion into the CNS by hemato-oncologists. Pretreatment magnetic resonance image (MRI) revealed gadolinium enhancement of the first genu and meatal portion of the facial nerve. After chemotherapy, although the ALL tumor cells disappeared from both the blood and the cerebrospinal fluid, and the facial palsy resolved, a posttreatment MRI showed no change in terms of enhancement of the facial nerve. These findings indicated the possibility of herpetic viral reactivation in the geniculate ganglion of the facial nerve. We must be aware and discuss with hemato-oncologists the possibility that not only tumor cell invasion into the CNS, in accordance with the guidelines, but also that herpetic virus reactivation arising in the facial nerve may be causes of facial palsy.