West Syndrome in Hypothalamic Hamartoma: A Rare Clinical Presentation

Background: Hypothalamic hamartoma (HH) is a congenital malformation of the hypothalamus, which presents with precocious puberty or seizures. The typical semiology includes gelastic seizures (GS), often beginning during early infancy. Most children develop complex partial and generalized seizure types over time. Infrequently, infantile spasms (IS) are the presenting seizure type. Initially, EEG is often unremarkable, but with progression of epilepsy, epileptiform activity occurs on interictal EEG. However, hypsarrhythmia is a rarity in HH, even in the presence of IS.

Methods: We report two patients who presented with West syndrome, the classical triad of infantile spasms, hypsarrhythmia, and developmental regression, as a symptom of HH.

Results: Patient 1 was a previously healthy boy, presenting with IS and hypsarrhythmia at 5 month of age. Patient 2 was a girl with a Pallister-Hall syndrome, also presenting with IS and hypsarrhythmia during infancy. Both patients had previously unrecognized GS. Steroid treatment was promptly followed by complete remission of West syndrome but persistent GS, complex partial seizures and developmental regression. Endoscopic resection of hamartoma took place at 12 and 24 month of age, respectively. Both patients remained seizure free without medication after surgery and showed improved development.

Conclusion: HH should be included in the differential diagnosis for infants presenting with West syndrome. It is important to ask for GS explicitly, which often remain undetected in infancy. Persistent complex partial and GS lead to developmental impairment. This implicates that early diagnosis of HH with subsequent option for surgical treatment is important, even if response of West syndrome to steroid treatment is prompt.