Free Communications: Neuropathology

Abstract

Abstract *ShujiWakai, *KokiNikaido, *HiroshiNihira, *YoshitakaKawamoto, *HiroyukiHayasaka, †TatsuyaTanaka, ‡TomokatsuHori, and §JeanRegis *Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo ; †Department of Neurosurgery, Asahikawa Medical College, Ashikawa ; ‡Department of Neurosurgery, Tokyo Women's Medical University , and §Department of Neurosurgery, La Simone Hospital, Tokyo, Japan Purpose: Epilepsies are often associated with hypothalamic hamartoma (HH). We present here two children with epilepsies caused by HHs, one with infantile spasms and the other with gelastic epilepsy, and report the EEG findings of each case and the magnetic resonance (MR) spectrometry of patient 2. Methods and Results: : Patient 1 is a 8-year-old boy at present. He developed infantile spasms at age 5 months. The EEG showed typical hypsarrhythmic pattern. Brain MRI revealed that he had HH, which was classified as IIb according to Valudueza's classification. His seizures soon subsided after treatment with adrenocorticotropic hormone (ACTH) therapy and, although transient precocious puberty has occurred, he has shown normal psychomotor development. Infantile spasms associated with HH are very rare, and this case suggested the possibility that a focal lesion gave rise to the infantile spasms. Patient 2 is a 4-year-old girl. At age 2 and half years, she developed brief, repetitive laughing attacks or mixed attacks with laughing and crying, which were refractory to carbamazepine. An interictal EEG showed intermittent slow waves in the left frontocentral region, and sporadic positive sharp waves in the left centroparietal area. Ictal EEG demonstrated dysrhythmic theta activity in the left central area 3 s after the onset of laughing. Brain MRI demonstrated a large sessile mass, isointense to gray matter, in the region of the hypothalamus, suggesting HH. The HH was classified as IIb according to Valudueza's classification. Proton MR spectrometry of the HH revealed a significant reduction of the N-acetyl aspartic acid/creatine ratio. Conclusions: Patient 1 had infantile spasms associated with HH. This combination is very rare and suggested the possibility that a focal lesion gave rise to the infantile spasms. Patient 2 showed altered chemical shift imaging with MR spectrometry, suggesting biochemical abnormality in the tissue of the HH. Moreover, this abnormal function of the HH tissue might be closely related to epileptogenesis because the time difference between the ictal laughter and the subsequent EEG changes in the ictal EEG does not support the idea that the activated cortex is the epileptogenic focus.