Myoclonic status epilepticus (MSE) within the first 24 hours after cardiopulmonary resuscitation (CPR) predicts poor prognosis, enough to discontinue the treatment. In contrast, chronic MSE appearing a few days after CPR is called Lance-Adams syndrome (LAS), which is characterized by preserved intellect and a favorable prognosis. We herein report a case of LAS, which developed after a transient hypoxic event without an overt cardiac arrest due to hematoma formation in the neck after partial glossectomy. Differential diagnosis was also challenging as LAS was developed 8 hours after the hypoxic event.