Unusual presentation of hypothalamic hamartoma with hypersomnia in an adult patient.

We report a patient with polysomnography findings related to hypersomnia, as a primary presenting symptom, who was shown to have stereotypical gelastic seizures. Her cranial magnetic resonance imaging revealed a hypothalamic hamartoma in the posterior region of the hypothalamus. The patient had no previous history of gelastic seizures. We suggest that patients who present with hypersomnia should be investigated for gelastic seizures in order to avoid misdiagnosis and receive appropriate treatment.