Hypothalamic Hamartomas and Seizures: Distinct Natural History of Isolated and Pallister-Hall Syndrome Cases

Summary: Purpose: Hypothalamic hamartomas (HHs) have been associated with uncontrolled seizures, and aggressive therapy including surgery is often recommended. However, some patients, particularly those with other findings associated with Pallister-Hall syndrome (PHS), have a more benign course.

Methods: Thirty-seven of 40 PHS patients and 16 of 16 patients with isolated HH had a lesion confirmed on magnetic resonance imaging (MRI). Records for all patients were reviewed for the following information: presence of seizures, age at seizure onset, seizure type, seizure frequency, number of antiepileptic medications (AEDs) at the time of evaluation, past AEDs, MRI characteristics of the HH, presence of endocrine dysfunction, and presence of developmental and behavioral problems.

Results: All isolated HH patients had a history of seizures, compared with 13 of 40 PHS patients (all PHS patients with seizures had hamartomas). In isolated HH, seizures started earlier in life, occurred more frequently, and were harder to control than those in patients with PHS. Isolated HH patients were more likely to have behavioral and developmental problems than were PHS patients. The T₂ signal of the hamartoma was isointense to gray matter in the majority of PHS patients, but showed a significant increase in all but one patient with isolated HH.

Conclusions: Patients with isolated HH have a distinct clinical phenotype, showing more severe seizures and neurologic dysfunction, HH showing increased T₂ signal, and are more likely to have precocious puberty. In contrast, PHS patients usually have well-controlled seizures and other endocrine disturbances than precocious puberty. Patients with HH with or without seizures should be evaluated carefully for other clinical manifestations of PHS, particularly before surgery is considered.